aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/flatbuffers/src/idl_parser.cpp
blob: 8b4f11685442ab1ad382432892496fc1fe539889 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
/*
 * Copyright 2014 Google Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <algorithm>
#include <cmath>
#include <iostream>
#include <list>
#include <string>
#include <utility>

#include "flatbuffers/base.h"
#include "flatbuffers/buffer.h"
#include "flatbuffers/idl.h"
#include "flatbuffers/reflection_generated.h"
#include "flatbuffers/util.h"

namespace flatbuffers {

// Reflects the version at the compiling time of binary(lib/dll/so).
const char *FLATBUFFERS_VERSION() {
  // clang-format off
  return
      FLATBUFFERS_STRING(FLATBUFFERS_VERSION_MAJOR) "."
      FLATBUFFERS_STRING(FLATBUFFERS_VERSION_MINOR) "."
      FLATBUFFERS_STRING(FLATBUFFERS_VERSION_REVISION);
  // clang-format on
}

namespace {

static const double kPi = 3.14159265358979323846;

// The enums in the reflection schema should match the ones we use internally.
// Compare the last element to check if these go out of sync.
static_assert(BASE_TYPE_VECTOR64 ==
                  static_cast<BaseType>(reflection::MaxBaseType - 1),
              "enums don't match");

// Any parsing calls have to be wrapped in this macro, which automates
// handling of recursive error checking a bit. It will check the received
// CheckedError object, and return straight away on error.
#define ECHECK(call)           \
  {                            \
    auto ce = (call);          \
    if (ce.Check()) return ce; \
  }

// These two functions are called hundreds of times below, so define a short
// form:
#define NEXT() ECHECK(Next())
#define EXPECT(tok) ECHECK(Expect(tok))

static bool ValidateUTF8(const std::string &str) {
  const char *s = &str[0];
  const char *const sEnd = s + str.length();
  while (s < sEnd) {
    if (FromUTF8(&s) < 0) { return false; }
  }
  return true;
}

static bool IsLowerSnakeCase(const std::string &str) {
  for (size_t i = 0; i < str.length(); i++) {
    char c = str[i];
    if (!check_ascii_range(c, 'a', 'z') && !is_digit(c) && c != '_') {
      return false;
    }
  }
  return true;
}

static void DeserializeDoc(std::vector<std::string> &doc,
                           const Vector<Offset<String>> *documentation) {
  if (documentation == nullptr) return;
  for (uoffset_t index = 0; index < documentation->size(); index++)
    doc.push_back(documentation->Get(index)->str());
}

static CheckedError NoError() { return CheckedError(false); }

template<typename T> static std::string TypeToIntervalString() {
  return "[" + NumToString((flatbuffers::numeric_limits<T>::lowest)()) + "; " +
         NumToString((flatbuffers::numeric_limits<T>::max)()) + "]";
}

// atot: template version of atoi/atof: convert a string to an instance of T.
template<typename T>
static bool atot_scalar(const char *s, T *val, bool_constant<false>) {
  return StringToNumber(s, val);
}

template<typename T>
static bool atot_scalar(const char *s, T *val, bool_constant<true>) {
  // Normalize NaN parsed from fbs or json to unsigned NaN.
  if (false == StringToNumber(s, val)) return false;
  *val = (*val != *val) ? std::fabs(*val) : *val;
  return true;
}

template<typename T>
static CheckedError atot(const char *s, Parser &parser, T *val) {
  auto done = atot_scalar(s, val, bool_constant<is_floating_point<T>::value>());
  if (done) return NoError();
  if (0 == *val)
    return parser.Error("invalid number: \"" + std::string(s) + "\"");
  else
    return parser.Error("invalid number: \"" + std::string(s) + "\"" +
                        ", constant does not fit " + TypeToIntervalString<T>());
}
template<>
CheckedError atot<Offset<void>>(const char *s, Parser &parser,
                                Offset<void> *val) {
  (void)parser;
  *val = Offset<void>(atoi(s));
  return NoError();
}

template<>
CheckedError atot<Offset64<void>>(const char *s, Parser &parser,
                                  Offset64<void> *val) {
  (void)parser;
  *val = Offset64<void>(atoi(s));
  return NoError();
}

template<typename T>
static T *LookupTableByName(const SymbolTable<T> &table,
                            const std::string &name,
                            const Namespace &current_namespace,
                            size_t skip_top) {
  const auto &components = current_namespace.components;
  if (table.dict.empty()) return nullptr;
  if (components.size() < skip_top) return nullptr;
  const auto N = components.size() - skip_top;
  std::string full_name;
  for (size_t i = 0; i < N; i++) {
    full_name += components[i];
    full_name += '.';
  }
  for (size_t i = N; i > 0; i--) {
    full_name += name;
    auto obj = table.Lookup(full_name);
    if (obj) return obj;
    auto len = full_name.size() - components[i - 1].size() - 1 - name.size();
    full_name.resize(len);
  }
  FLATBUFFERS_ASSERT(full_name.empty());
  return table.Lookup(name);  // lookup in global namespace
}

// Declare tokens we'll use. Single character tokens are represented by their
// ascii character code (e.g. '{'), others above 256.
// clang-format off
#define FLATBUFFERS_GEN_TOKENS(TD) \
  TD(Eof, 256, "end of file") \
  TD(StringConstant, 257, "string constant") \
  TD(IntegerConstant, 258, "integer constant") \
  TD(FloatConstant, 259, "float constant") \
  TD(Identifier, 260, "identifier")
#ifdef __GNUC__
__extension__  // Stop GCC complaining about trailing comma with -Wpendantic.
#endif
enum {
  #define FLATBUFFERS_TOKEN(NAME, VALUE, STRING) kToken ## NAME = VALUE,
    FLATBUFFERS_GEN_TOKENS(FLATBUFFERS_TOKEN)
  #undef FLATBUFFERS_TOKEN
};

static std::string TokenToString(int t) {
  static const char * const tokens[] = {
    #define FLATBUFFERS_TOKEN(NAME, VALUE, STRING) STRING,
      FLATBUFFERS_GEN_TOKENS(FLATBUFFERS_TOKEN)
    #undef FLATBUFFERS_TOKEN
    #define FLATBUFFERS_TD(ENUM, IDLTYPE, ...) \
      IDLTYPE,
      FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
    #undef FLATBUFFERS_TD
  };
  if (t < 256) {  // A single ascii char token.
    std::string s;
    s.append(1, static_cast<char>(t));
    return s;
  } else {       // Other tokens.
    return tokens[t - 256];
  }
}
// clang-format on

static bool IsIdentifierStart(char c) { return is_alpha(c) || (c == '_'); }

static bool CompareSerializedScalars(const uint8_t *a, const uint8_t *b,
                                     const FieldDef &key) {
  switch (key.value.type.base_type) {
#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...)                       \
  case BASE_TYPE_##ENUM: {                                              \
    CTYPE def = static_cast<CTYPE>(0);                                  \
    if (!a || !b) { StringToNumber(key.value.constant.c_str(), &def); } \
    const auto av = a ? ReadScalar<CTYPE>(a) : def;                     \
    const auto bv = b ? ReadScalar<CTYPE>(b) : def;                     \
    return av < bv;                                                     \
  }
    FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD)
#undef FLATBUFFERS_TD
    default: {
      FLATBUFFERS_ASSERT(false && "scalar type expected");
      return false;
    }
  }
}

static bool CompareTablesByScalarKey(const Offset<Table> *_a,
                                     const Offset<Table> *_b,
                                     const FieldDef &key) {
  const voffset_t offset = key.value.offset;
  // Indirect offset pointer to table pointer.
  auto a = reinterpret_cast<const uint8_t *>(_a) + ReadScalar<uoffset_t>(_a);
  auto b = reinterpret_cast<const uint8_t *>(_b) + ReadScalar<uoffset_t>(_b);
  // Fetch field address from table.
  a = reinterpret_cast<const Table *>(a)->GetAddressOf(offset);
  b = reinterpret_cast<const Table *>(b)->GetAddressOf(offset);
  return CompareSerializedScalars(a, b, key);
}

static bool CompareTablesByStringKey(const Offset<Table> *_a,
                                     const Offset<Table> *_b,
                                     const FieldDef &key) {
  const voffset_t offset = key.value.offset;
  // Indirect offset pointer to table pointer.
  auto a = reinterpret_cast<const uint8_t *>(_a) + ReadScalar<uoffset_t>(_a);
  auto b = reinterpret_cast<const uint8_t *>(_b) + ReadScalar<uoffset_t>(_b);
  // Fetch field address from table.
  a = reinterpret_cast<const Table *>(a)->GetAddressOf(offset);
  b = reinterpret_cast<const Table *>(b)->GetAddressOf(offset);
  if (a && b) {
    // Indirect offset pointer to string pointer.
    a += ReadScalar<uoffset_t>(a);
    b += ReadScalar<uoffset_t>(b);
    return *reinterpret_cast<const String *>(a) <
           *reinterpret_cast<const String *>(b);
  } else {
    return a ? true : false;
  }
}

static void SwapSerializedTables(Offset<Table> *a, Offset<Table> *b) {
  // These are serialized offsets, so are relative where they are
  // stored in memory, so compute the distance between these pointers:
  ptrdiff_t diff = (b - a) * sizeof(Offset<Table>);
  FLATBUFFERS_ASSERT(diff >= 0);  // Guaranteed by SimpleQsort.
  auto udiff = static_cast<uoffset_t>(diff);
  a->o = EndianScalar(ReadScalar<uoffset_t>(a) - udiff);
  b->o = EndianScalar(ReadScalar<uoffset_t>(b) + udiff);
  std::swap(*a, *b);
}

// See below for why we need our own sort :(
template<typename T, typename F, typename S>
static void SimpleQsort(T *begin, T *end, size_t width, F comparator,
                        S swapper) {
  if (end - begin <= static_cast<ptrdiff_t>(width)) return;
  auto l = begin + width;
  auto r = end;
  while (l < r) {
    if (comparator(begin, l)) {
      r -= width;
      swapper(l, r);
    } else {
      l += width;
    }
  }
  l -= width;
  swapper(begin, l);
  SimpleQsort(begin, l, width, comparator, swapper);
  SimpleQsort(r, end, width, comparator, swapper);
}

template<typename T> static inline void SingleValueRepack(Value &e, T val) {
  // Remove leading zeros.
  if (IsInteger(e.type.base_type)) { e.constant = NumToString(val); }
}

#if defined(FLATBUFFERS_HAS_NEW_STRTOD) && (FLATBUFFERS_HAS_NEW_STRTOD > 0)
// Normalize defaults NaN to unsigned quiet-NaN(0) if value was parsed from
// hex-float literal.
static void SingleValueRepack(Value &e, float val) {
  if (val != val) e.constant = "nan";
}
static void SingleValueRepack(Value &e, double val) {
  if (val != val) e.constant = "nan";
}
#endif

template<typename T> static uint64_t EnumDistanceImpl(T e1, T e2) {
  if (e1 < e2) { std::swap(e1, e2); }  // use std for scalars
  // Signed overflow may occur, use unsigned calculation.
  // The unsigned overflow is well-defined by C++ standard (modulo 2^n).
  return static_cast<uint64_t>(e1) - static_cast<uint64_t>(e2);
}

static bool compareFieldDefs(const FieldDef *a, const FieldDef *b) {
  auto a_id = atoi(a->attributes.Lookup("id")->constant.c_str());
  auto b_id = atoi(b->attributes.Lookup("id")->constant.c_str());
  return a_id < b_id;
}

static Namespace *GetNamespace(
    const std::string &qualified_name, std::vector<Namespace *> &namespaces,
    std::map<std::string, Namespace *> &namespaces_index) {
  size_t dot = qualified_name.find_last_of('.');
  std::string namespace_name = (dot != std::string::npos)
                                   ? std::string(qualified_name.c_str(), dot)
                                   : "";
  Namespace *&ns = namespaces_index[namespace_name];

  if (!ns) {
    ns = new Namespace();
    namespaces.push_back(ns);

    size_t pos = 0;

    for (;;) {
      dot = qualified_name.find('.', pos);
      if (dot == std::string::npos) { break; }
      ns->components.push_back(qualified_name.substr(pos, dot - pos));
      pos = dot + 1;
    }
  }

  return ns;
}

// Generate a unique hash for a file based on its name and contents (if any).
static uint64_t HashFile(const char *source_filename, const char *source) {
  uint64_t hash = 0;

  if (source_filename)
    hash = HashFnv1a<uint64_t>(StripPath(source_filename).c_str());

  if (source && *source) hash ^= HashFnv1a<uint64_t>(source);

  return hash;
}

template<typename T> static bool compareName(const T *a, const T *b) {
  return a->defined_namespace->GetFullyQualifiedName(a->name) <
         b->defined_namespace->GetFullyQualifiedName(b->name);
}

template<typename T> static void AssignIndices(const std::vector<T *> &defvec) {
  // Pre-sort these vectors, such that we can set the correct indices for them.
  auto vec = defvec;
  std::sort(vec.begin(), vec.end(), compareName<T>);
  for (int i = 0; i < static_cast<int>(vec.size()); i++) vec[i]->index = i;
}

}  // namespace

void Parser::Message(const std::string &msg) {
  if (!error_.empty()) error_ += "\n";  // log all warnings and errors
  error_ += file_being_parsed_.length() ? AbsolutePath(file_being_parsed_) : "";
  // clang-format off

  #ifdef _WIN32  // MSVC alike
    error_ +=
        "(" + NumToString(line_) + ", " + NumToString(CursorPosition()) + ")";
  #else  // gcc alike
    if (file_being_parsed_.length()) error_ += ":";
    error_ += NumToString(line_) + ": " + NumToString(CursorPosition());
  #endif
  // clang-format on
  error_ += ": " + msg;
}

void Parser::Warning(const std::string &msg) {
  if (!opts.no_warnings) {
    Message("warning: " + msg);
    has_warning_ = true;  // for opts.warnings_as_errors
  }
}

CheckedError Parser::Error(const std::string &msg) {
  Message("error: " + msg);
  return CheckedError(true);
}

CheckedError Parser::RecurseError() {
  return Error("maximum parsing depth " + NumToString(parse_depth_counter_) +
               " reached");
}

const std::string &Parser::GetPooledString(const std::string &s) const {
  return *(string_cache_.insert(s).first);
}

class Parser::ParseDepthGuard {
 public:
  explicit ParseDepthGuard(Parser *parser_not_null)
      : parser_(*parser_not_null), caller_depth_(parser_.parse_depth_counter_) {
    FLATBUFFERS_ASSERT(caller_depth_ <= (FLATBUFFERS_MAX_PARSING_DEPTH) &&
                       "Check() must be called to prevent stack overflow");
    parser_.parse_depth_counter_ += 1;
  }

  ~ParseDepthGuard() { parser_.parse_depth_counter_ -= 1; }

  CheckedError Check() {
    return caller_depth_ >= (FLATBUFFERS_MAX_PARSING_DEPTH)
               ? parser_.RecurseError()
               : CheckedError(false);
  }

  FLATBUFFERS_DELETE_FUNC(ParseDepthGuard(const ParseDepthGuard &));
  FLATBUFFERS_DELETE_FUNC(ParseDepthGuard &operator=(const ParseDepthGuard &));

 private:
  Parser &parser_;
  const int caller_depth_;
};

std::string Namespace::GetFullyQualifiedName(const std::string &name,
                                             size_t max_components) const {
  // Early exit if we don't have a defined namespace.
  if (components.empty() || !max_components) { return name; }
  std::string stream_str;
  for (size_t i = 0; i < std::min(components.size(), max_components); i++) {
    stream_str += components[i];
    stream_str += '.';
  }
  if (!stream_str.empty()) stream_str.pop_back();
  if (name.length()) {
    stream_str += '.';
    stream_str += name;
  }
  return stream_str;
}

std::string Parser::TokenToStringId(int t) const {
  return t == kTokenIdentifier ? attribute_ : TokenToString(t);
}

// Parses exactly nibbles worth of hex digits into a number, or error.
CheckedError Parser::ParseHexNum(int nibbles, uint64_t *val) {
  FLATBUFFERS_ASSERT(nibbles > 0);
  for (int i = 0; i < nibbles; i++)
    if (!is_xdigit(cursor_[i]))
      return Error("escape code must be followed by " + NumToString(nibbles) +
                   " hex digits");
  std::string target(cursor_, cursor_ + nibbles);
  *val = StringToUInt(target.c_str(), 16);
  cursor_ += nibbles;
  return NoError();
}

CheckedError Parser::SkipByteOrderMark() {
  if (static_cast<unsigned char>(*cursor_) != 0xef) return NoError();
  cursor_++;
  if (static_cast<unsigned char>(*cursor_) != 0xbb)
    return Error("invalid utf-8 byte order mark");
  cursor_++;
  if (static_cast<unsigned char>(*cursor_) != 0xbf)
    return Error("invalid utf-8 byte order mark");
  cursor_++;
  return NoError();
}

CheckedError Parser::Next() {
  doc_comment_.clear();
  prev_cursor_ = cursor_;
  bool seen_newline = cursor_ == source_;
  attribute_.clear();
  attr_is_trivial_ascii_string_ = true;
  for (;;) {
    char c = *cursor_++;
    token_ = c;
    switch (c) {
      case '\0':
        cursor_--;
        token_ = kTokenEof;
        return NoError();
      case ' ':
      case '\r':
      case '\t': break;
      case '\n':
        MarkNewLine();
        seen_newline = true;
        break;
      case '{':
      case '}':
      case '(':
      case ')':
      case '[':
      case ']':
      case '<':
      case '>':
      case ',':
      case ':':
      case ';':
      case '=': return NoError();
      case '\"':
      case '\'': {
        int unicode_high_surrogate = -1;

        while (*cursor_ != c) {
          if (*cursor_ < ' ' && static_cast<signed char>(*cursor_) >= 0)
            return Error("illegal character in string constant");
          if (*cursor_ == '\\') {
            attr_is_trivial_ascii_string_ = false;  // has escape sequence
            cursor_++;
            if (unicode_high_surrogate != -1 && *cursor_ != 'u') {
              return Error(
                  "illegal Unicode sequence (unpaired high surrogate)");
            }
            switch (*cursor_) {
              case 'n':
                attribute_ += '\n';
                cursor_++;
                break;
              case 't':
                attribute_ += '\t';
                cursor_++;
                break;
              case 'r':
                attribute_ += '\r';
                cursor_++;
                break;
              case 'b':
                attribute_ += '\b';
                cursor_++;
                break;
              case 'f':
                attribute_ += '\f';
                cursor_++;
                break;
              case '\"':
                attribute_ += '\"';
                cursor_++;
                break;
              case '\'':
                attribute_ += '\'';
                cursor_++;
                break;
              case '\\':
                attribute_ += '\\';
                cursor_++;
                break;
              case '/':
                attribute_ += '/';
                cursor_++;
                break;
              case 'x': {  // Not in the JSON standard
                cursor_++;
                uint64_t val;
                ECHECK(ParseHexNum(2, &val));
                attribute_ += static_cast<char>(val);
                break;
              }
              case 'u': {
                cursor_++;
                uint64_t val;
                ECHECK(ParseHexNum(4, &val));
                if (val >= 0xD800 && val <= 0xDBFF) {
                  if (unicode_high_surrogate != -1) {
                    return Error(
                        "illegal Unicode sequence (multiple high surrogates)");
                  } else {
                    unicode_high_surrogate = static_cast<int>(val);
                  }
                } else if (val >= 0xDC00 && val <= 0xDFFF) {
                  if (unicode_high_surrogate == -1) {
                    return Error(
                        "illegal Unicode sequence (unpaired low surrogate)");
                  } else {
                    int code_point = 0x10000 +
                                     ((unicode_high_surrogate & 0x03FF) << 10) +
                                     (val & 0x03FF);
                    ToUTF8(code_point, &attribute_);
                    unicode_high_surrogate = -1;
                  }
                } else {
                  if (unicode_high_surrogate != -1) {
                    return Error(
                        "illegal Unicode sequence (unpaired high surrogate)");
                  }
                  ToUTF8(static_cast<int>(val), &attribute_);
                }
                break;
              }
              default: return Error("unknown escape code in string constant");
            }
          } else {  // printable chars + UTF-8 bytes
            if (unicode_high_surrogate != -1) {
              return Error(
                  "illegal Unicode sequence (unpaired high surrogate)");
            }
            // reset if non-printable
            attr_is_trivial_ascii_string_ &=
                check_ascii_range(*cursor_, ' ', '~');

            attribute_ += *cursor_++;
          }
        }
        if (unicode_high_surrogate != -1) {
          return Error("illegal Unicode sequence (unpaired high surrogate)");
        }
        cursor_++;
        if (!attr_is_trivial_ascii_string_ && !opts.allow_non_utf8 &&
            !ValidateUTF8(attribute_)) {
          return Error("illegal UTF-8 sequence");
        }
        token_ = kTokenStringConstant;
        return NoError();
      }
      case '/':
        if (*cursor_ == '/') {
          const char *start = ++cursor_;
          while (*cursor_ && *cursor_ != '\n' && *cursor_ != '\r') cursor_++;
          if (*start == '/') {  // documentation comment
            if (!seen_newline)
              return Error(
                  "a documentation comment should be on a line on its own");
            doc_comment_.push_back(std::string(start + 1, cursor_));
          }
          break;
        } else if (*cursor_ == '*') {
          cursor_++;
          // TODO: make nested.
          while (*cursor_ != '*' || cursor_[1] != '/') {
            if (*cursor_ == '\n') MarkNewLine();
            if (!*cursor_) return Error("end of file in comment");
            cursor_++;
          }
          cursor_ += 2;
          break;
        }
        FLATBUFFERS_FALLTHROUGH();  // else fall thru
      default:
        if (IsIdentifierStart(c)) {
          // Collect all chars of an identifier:
          const char *start = cursor_ - 1;
          while (IsIdentifierStart(*cursor_) || is_digit(*cursor_)) cursor_++;
          attribute_.append(start, cursor_);
          token_ = kTokenIdentifier;
          return NoError();
        }

        const auto has_sign = (c == '+') || (c == '-');
        if (has_sign) {
          // Check for +/-inf which is considered a float constant.
          if (strncmp(cursor_, "inf", 3) == 0 &&
              !(IsIdentifierStart(cursor_[3]) || is_digit(cursor_[3]))) {
            attribute_.assign(cursor_ - 1, cursor_ + 3);
            token_ = kTokenFloatConstant;
            cursor_ += 3;
            return NoError();
          }

          if (IsIdentifierStart(*cursor_)) {
            // '-'/'+' and following identifier - it could be a predefined
            // constant. Return the sign in token_, see ParseSingleValue.
            return NoError();
          }
        }

        auto dot_lvl =
            (c == '.') ? 0 : 1;  // dot_lvl==0 <=> exactly one '.' seen
        if (!dot_lvl && !is_digit(*cursor_)) return NoError();  // enum?
        // Parser accepts hexadecimal-floating-literal (see C++ 5.13.4).
        if (is_digit(c) || has_sign || !dot_lvl) {
          const auto start = cursor_ - 1;
          auto start_digits = !is_digit(c) ? cursor_ : cursor_ - 1;
          if (!is_digit(c) && is_digit(*cursor_)) {
            start_digits = cursor_;  // see digit in cursor_ position
            c = *cursor_++;
          }
          // hex-float can't begind with '.'
          auto use_hex = dot_lvl && (c == '0') && is_alpha_char(*cursor_, 'X');
          if (use_hex) start_digits = ++cursor_;  // '0x' is the prefix, skip it
          // Read an integer number or mantisa of float-point number.
          do {
            if (use_hex) {
              while (is_xdigit(*cursor_)) cursor_++;
            } else {
              while (is_digit(*cursor_)) cursor_++;
            }
          } while ((*cursor_ == '.') && (++cursor_) && (--dot_lvl >= 0));
          // Exponent of float-point number.
          if ((dot_lvl >= 0) && (cursor_ > start_digits)) {
            // The exponent suffix of hexadecimal float number is mandatory.
            if (use_hex && !dot_lvl) start_digits = cursor_;
            if ((use_hex && is_alpha_char(*cursor_, 'P')) ||
                is_alpha_char(*cursor_, 'E')) {
              dot_lvl = 0;  // Emulate dot to signal about float-point number.
              cursor_++;
              if (*cursor_ == '+' || *cursor_ == '-') cursor_++;
              start_digits = cursor_;  // the exponent-part has to have digits
              // Exponent is decimal integer number
              while (is_digit(*cursor_)) cursor_++;
              if (*cursor_ == '.') {
                cursor_++;  // If see a dot treat it as part of invalid number.
                dot_lvl = -1;  // Fall thru to Error().
              }
            }
          }
          // Finalize.
          if ((dot_lvl >= 0) && (cursor_ > start_digits)) {
            attribute_.append(start, cursor_);
            token_ = dot_lvl ? kTokenIntegerConstant : kTokenFloatConstant;
            return NoError();
          } else {
            return Error("invalid number: " + std::string(start, cursor_));
          }
        }
        std::string ch;
        ch = c;
        if (false == check_ascii_range(c, ' ', '~'))
          ch = "code: " + NumToString(c);
        return Error("illegal character: " + ch);
    }
  }
}

// Check if a given token is next.
bool Parser::Is(int t) const { return t == token_; }

bool Parser::IsIdent(const char *id) const {
  return token_ == kTokenIdentifier && attribute_ == id;
}

// Expect a given token to be next, consume it, or error if not present.
CheckedError Parser::Expect(int t) {
  if (t != token_) {
    return Error("expecting: " + TokenToString(t) +
                 " instead got: " + TokenToStringId(token_));
  }
  NEXT();
  return NoError();
}

CheckedError Parser::ParseNamespacing(std::string *id, std::string *last) {
  while (Is('.')) {
    NEXT();
    *id += ".";
    *id += attribute_;
    if (last) *last = attribute_;
    EXPECT(kTokenIdentifier);
  }
  return NoError();
}

EnumDef *Parser::LookupEnum(const std::string &id) {
  // Search thru parent namespaces.
  return LookupTableByName(enums_, id, *current_namespace_, 0);
}

StructDef *Parser::LookupStruct(const std::string &id) const {
  auto sd = structs_.Lookup(id);
  if (sd) sd->refcount++;
  return sd;
}

StructDef *Parser::LookupStructThruParentNamespaces(
    const std::string &id) const {
  auto sd = LookupTableByName(structs_, id, *current_namespace_, 1);
  if (sd) sd->refcount++;
  return sd;
}

CheckedError Parser::ParseTypeIdent(Type &type) {
  std::string id = attribute_;
  EXPECT(kTokenIdentifier);
  ECHECK(ParseNamespacing(&id, nullptr));
  auto enum_def = LookupEnum(id);
  if (enum_def) {
    type = enum_def->underlying_type;
    if (enum_def->is_union) type.base_type = BASE_TYPE_UNION;
  } else {
    type.base_type = BASE_TYPE_STRUCT;
    type.struct_def = LookupCreateStruct(id);
  }
  return NoError();
}

// Parse any IDL type.
CheckedError Parser::ParseType(Type &type) {
  if (token_ == kTokenIdentifier) {
    if (IsIdent("bool")) {
      type.base_type = BASE_TYPE_BOOL;
      NEXT();
    } else if (IsIdent("byte") || IsIdent("int8")) {
      type.base_type = BASE_TYPE_CHAR;
      NEXT();
    } else if (IsIdent("ubyte") || IsIdent("uint8")) {
      type.base_type = BASE_TYPE_UCHAR;
      NEXT();
    } else if (IsIdent("short") || IsIdent("int16")) {
      type.base_type = BASE_TYPE_SHORT;
      NEXT();
    } else if (IsIdent("ushort") || IsIdent("uint16")) {
      type.base_type = BASE_TYPE_USHORT;
      NEXT();
    } else if (IsIdent("int") || IsIdent("int32")) {
      type.base_type = BASE_TYPE_INT;
      NEXT();
    } else if (IsIdent("uint") || IsIdent("uint32")) {
      type.base_type = BASE_TYPE_UINT;
      NEXT();
    } else if (IsIdent("long") || IsIdent("int64")) {
      type.base_type = BASE_TYPE_LONG;
      NEXT();
    } else if (IsIdent("ulong") || IsIdent("uint64")) {
      type.base_type = BASE_TYPE_ULONG;
      NEXT();
    } else if (IsIdent("float") || IsIdent("float32")) {
      type.base_type = BASE_TYPE_FLOAT;
      NEXT();
    } else if (IsIdent("double") || IsIdent("float64")) {
      type.base_type = BASE_TYPE_DOUBLE;
      NEXT();
    } else if (IsIdent("string")) {
      type.base_type = BASE_TYPE_STRING;
      NEXT();
    } else {
      ECHECK(ParseTypeIdent(type));
    }
  } else if (token_ == '[') {
    ParseDepthGuard depth_guard(this);
    ECHECK(depth_guard.Check());
    NEXT();
    Type subtype;
    ECHECK(ParseType(subtype));
    if (IsSeries(subtype)) {
      // We could support this, but it will complicate things, and it's
      // easier to work around with a struct around the inner vector.
      return Error("nested vector types not supported (wrap in table first)");
    }
    if (token_ == ':') {
      NEXT();
      if (token_ != kTokenIntegerConstant) {
        return Error("length of fixed-length array must be an integer value");
      }
      uint16_t fixed_length = 0;
      bool check = StringToNumber(attribute_.c_str(), &fixed_length);
      if (!check || fixed_length < 1) {
        return Error(
            "length of fixed-length array must be positive and fit to "
            "uint16_t type");
      }
      type = Type(BASE_TYPE_ARRAY, subtype.struct_def, subtype.enum_def,
                  fixed_length);
      NEXT();
    } else {
      type = Type(BASE_TYPE_VECTOR, subtype.struct_def, subtype.enum_def);
    }
    type.element = subtype.base_type;
    EXPECT(']');
  } else {
    return Error("illegal type syntax");
  }
  return NoError();
}

CheckedError Parser::AddField(StructDef &struct_def, const std::string &name,
                              const Type &type, FieldDef **dest) {
  auto &field = *new FieldDef();
  field.value.offset =
      FieldIndexToOffset(static_cast<voffset_t>(struct_def.fields.vec.size()));
  field.name = name;
  field.file = struct_def.file;
  field.value.type = type;
  if (struct_def.fixed) {  // statically compute the field offset
    auto size = InlineSize(type);
    auto alignment = InlineAlignment(type);
    // structs_ need to have a predictable format, so we need to align to
    // the largest scalar
    struct_def.minalign = std::max(struct_def.minalign, alignment);
    struct_def.PadLastField(alignment);
    field.value.offset = static_cast<voffset_t>(struct_def.bytesize);
    struct_def.bytesize += size;
  }
  if (struct_def.fields.Add(name, &field))
    return Error("field already exists: " + name);
  *dest = &field;
  return NoError();
}

CheckedError Parser::ParseField(StructDef &struct_def) {
  std::string name = attribute_;

  if (LookupCreateStruct(name, false, false))
    return Error("field name can not be the same as table/struct name");

  if (!IsLowerSnakeCase(name)) {
    Warning("field names should be lowercase snake_case, got: " + name);
  }

  std::vector<std::string> dc = doc_comment_;
  EXPECT(kTokenIdentifier);
  EXPECT(':');
  Type type;
  ECHECK(ParseType(type));

  if (struct_def.fixed) {
    if (IsIncompleteStruct(type) ||
        (IsArray(type) && IsIncompleteStruct(type.VectorType()))) {
      std::string type_name = IsArray(type) ? type.VectorType().struct_def->name
                                            : type.struct_def->name;
      return Error(
          std::string("Incomplete type in struct is not allowed, type name: ") +
          type_name);
    }

    auto valid = IsScalar(type.base_type) || IsStruct(type);
    if (!valid && IsArray(type)) {
      const auto &elem_type = type.VectorType();
      valid |= IsScalar(elem_type.base_type) || IsStruct(elem_type);
    }
    if (!valid)
      return Error("structs may contain only scalar or struct fields");
  }

  if (!struct_def.fixed && IsArray(type))
    return Error("fixed-length array in table must be wrapped in struct");

  if (IsArray(type)) {
    advanced_features_ |= reflection::AdvancedArrayFeatures;
    if (!SupportsAdvancedArrayFeatures()) {
      return Error(
          "Arrays are not yet supported in all "
          "the specified programming languages.");
    }
  }

  FieldDef *typefield = nullptr;
  if (type.base_type == BASE_TYPE_UNION) {
    // For union fields, add a second auto-generated field to hold the type,
    // with a special suffix.

    // To ensure compatibility with many codes that rely on the BASE_TYPE_UTYPE value to identify union type fields.
    Type union_type(type.enum_def->underlying_type);
    union_type.base_type = BASE_TYPE_UTYPE;
    ECHECK(AddField(struct_def, name + UnionTypeFieldSuffix(),union_type, &typefield));
    
  } else if (IsVector(type) && type.element == BASE_TYPE_UNION) {
    advanced_features_ |= reflection::AdvancedUnionFeatures;
    // Only cpp, js and ts supports the union vector feature so far.
    if (!SupportsAdvancedUnionFeatures()) {
      return Error(
          "Vectors of unions are not yet supported in at least one of "
          "the specified programming languages.");
    }
    // For vector of union fields, add a second auto-generated vector field to
    // hold the types, with a special suffix.
    Type union_vector(BASE_TYPE_VECTOR, nullptr, type.enum_def);
    union_vector.element = BASE_TYPE_UTYPE;
    ECHECK(AddField(struct_def, name + UnionTypeFieldSuffix(), union_vector,
                    &typefield));
  }

  FieldDef *field;
  ECHECK(AddField(struct_def, name, type, &field));

  if (typefield) {
    // We preserve the relation between the typefield
    // and field, so we can easily map it in the code
    // generators.
    typefield->sibling_union_field = field;
    field->sibling_union_field = typefield;
  }

  if (token_ == '=') {
    NEXT();
    ECHECK(ParseSingleValue(&field->name, field->value, true));
    if (IsStruct(type) || (struct_def.fixed && field->value.constant != "0"))
      return Error(
          "default values are not supported for struct fields, table fields, "
          "or in structs.");
    if (IsString(type) || IsVector(type)) {
      advanced_features_ |= reflection::DefaultVectorsAndStrings;
      if (field->value.constant != "0" && !SupportsDefaultVectorsAndStrings()) {
        return Error(
            "Default values for strings and vectors are not supported in one "
            "of the specified programming languages");
      }
    }

    if (IsVector(type) && field->value.constant != "0" &&
        field->value.constant != "[]") {
      return Error("The only supported default for vectors is `[]`.");
    }
  }

  // Append .0 if the value has not it (skip hex and scientific floats).
  // This suffix needed for generated C++ code.
  if (IsFloat(type.base_type)) {
    auto &text = field->value.constant;
    FLATBUFFERS_ASSERT(false == text.empty());
    auto s = text.c_str();
    while (*s == ' ') s++;
    if (*s == '-' || *s == '+') s++;
    // 1) A float constants (nan, inf, pi, etc) is a kind of identifier.
    // 2) A float number needn't ".0" at the end if it has exponent.
    if ((false == IsIdentifierStart(*s)) &&
        (std::string::npos == field->value.constant.find_first_of(".eEpP"))) {
      field->value.constant += ".0";
    }
  }

  field->doc_comment = dc;
  ECHECK(ParseMetaData(&field->attributes));
  field->deprecated = field->attributes.Lookup("deprecated") != nullptr;
  auto hash_name = field->attributes.Lookup("hash");
  if (hash_name) {
    switch ((IsVector(type)) ? type.element : type.base_type) {
      case BASE_TYPE_SHORT:
      case BASE_TYPE_USHORT: {
        if (FindHashFunction16(hash_name->constant.c_str()) == nullptr)
          return Error("Unknown hashing algorithm for 16 bit types: " +
                       hash_name->constant);
        break;
      }
      case BASE_TYPE_INT:
      case BASE_TYPE_UINT: {
        if (FindHashFunction32(hash_name->constant.c_str()) == nullptr)
          return Error("Unknown hashing algorithm for 32 bit types: " +
                       hash_name->constant);
        break;
      }
      case BASE_TYPE_LONG:
      case BASE_TYPE_ULONG: {
        if (FindHashFunction64(hash_name->constant.c_str()) == nullptr)
          return Error("Unknown hashing algorithm for 64 bit types: " +
                       hash_name->constant);
        break;
      }
      default:
        return Error(
            "only short, ushort, int, uint, long and ulong data types support "
            "hashing.");
    }
  }

  if (field->attributes.Lookup("vector64") != nullptr) {
    if (!IsVector(type)) {
      return Error("`vector64` attribute can only be applied on vectors.");
    }

    // Upgrade the type to be a BASE_TYPE_VECTOR64, since the attributes are
    // parsed after the type.
    const BaseType element_base_type = type.element;
    type = Type(BASE_TYPE_VECTOR64, type.struct_def, type.enum_def);
    type.element = element_base_type;

    // Since the field was already added to the parent object, update the type
    // in place.
    field->value.type = type;

    // 64-bit vectors imply the offset64 attribute.
    field->offset64 = true;
  }

  // Record that this field uses 64-bit offsets.
  if (field->attributes.Lookup("offset64") != nullptr) {
    // TODO(derekbailey): would be nice to have this be a recommendation or hint
    // instead of a warning.
    if (type.base_type == BASE_TYPE_VECTOR64) {
      Warning("attribute `vector64` implies `offset64` and isn't required.");
    }

    field->offset64 = true;
  }

  // Check for common conditions with Offset64 fields.
  if (field->offset64) {
    // TODO(derekbailey): this is where we can disable string support for
    // offset64, as that is not a hard requirement to have.
    if (!IsString(type) && !IsVector(type)) {
      return Error(
          "only string and vectors can have `offset64` attribute applied");
    }

    // If this is a Vector, only scalar and scalar-like (structs) items are
    // allowed.
    // TODO(derekbailey): allow vector of strings, just require that the strings
    // are Offset64<string>.
    if (IsVector(type) &&
        !((IsScalar(type.element) && !IsEnum(type.VectorType())) ||
          IsStruct(type.VectorType()))) {
      return Error("only vectors of scalars are allowed to be 64-bit.");
    }

    // Lastly, check if it is supported by the specified generated languages. Do
    // this last so the above checks can inform the user of schema errors to fix
    // first.
    if (!Supports64BitOffsets()) {
      return Error(
          "fields using 64-bit offsets are not yet supported in at least one "
          "of the specified programming languages.");
    }
  }

  // For historical convenience reasons, string keys are assumed required.
  // Scalars are kDefault unless otherwise specified.
  // Nonscalars are kOptional unless required;
  field->key = field->attributes.Lookup("key") != nullptr;
  const bool required = field->attributes.Lookup("required") != nullptr ||
                        (IsString(type) && field->key);
  const bool default_str_or_vec =
      ((IsString(type) || IsVector(type)) && field->value.constant != "0");
  const bool optional = IsScalar(type.base_type)
                            ? (field->value.constant == "null")
                            : !(required || default_str_or_vec);
  if (required && optional) {
    return Error("Fields cannot be both optional and required.");
  }
  field->presence = FieldDef::MakeFieldPresence(optional, required);

  if (required && (struct_def.fixed || IsScalar(type.base_type))) {
    return Error("only non-scalar fields in tables may be 'required'");
  }
  if (field->key) {
    if (struct_def.has_key) return Error("only one field may be set as 'key'");
    struct_def.has_key = true;
    auto is_valid =
        IsScalar(type.base_type) || IsString(type) || IsStruct(type);
    if (IsArray(type)) {
      is_valid |=
          IsScalar(type.VectorType().base_type) || IsStruct(type.VectorType());
    }
    if (!is_valid) {
      return Error(
          "'key' field must be string, scalar type or fixed size array of "
          "scalars");
    }
  }

  if (field->IsScalarOptional()) {
    advanced_features_ |= reflection::OptionalScalars;
    if (type.enum_def && type.enum_def->Lookup("null")) {
      FLATBUFFERS_ASSERT(IsInteger(type.base_type));
      return Error(
          "the default 'null' is reserved for declaring optional scalar "
          "fields, it conflicts with declaration of enum '" +
          type.enum_def->name + "'.");
    }
    if (field->attributes.Lookup("key")) {
      return Error(
          "only a non-optional scalar field can be used as a 'key' field");
    }
    if (!SupportsOptionalScalars()) {
      return Error(
          "Optional scalars are not yet supported in at least one of "
          "the specified programming languages.");
    }
  }

  if (type.enum_def) {
    // Verify the enum's type and default value.
    const std::string &constant = field->value.constant;
    if (type.base_type == BASE_TYPE_UNION) {
      if (constant != "0") { return Error("Union defaults must be NONE"); }
    } else if (IsVector(type)) {
      if (constant != "0" && constant != "[]") {
        return Error("Vector defaults may only be `[]`.");
      }
    } else if (IsArray(type)) {
      if (constant != "0") {
        return Error("Array defaults are not supported yet.");
      }
    } else {
      if (!IsInteger(type.base_type)) {
        return Error("Enums must have integer base types");
      }
      // Optional and bitflags enums may have default constants that are not
      // their specified variants.
      if (!field->IsOptional() &&
          type.enum_def->attributes.Lookup("bit_flags") == nullptr) {
        if (type.enum_def->FindByValue(constant) == nullptr) {
          return Error("default value of `" + constant + "` for " + "field `" +
                       name + "` is not part of enum `" + type.enum_def->name +
                       "`.");
        }
      }
    }
  }

  if (field->deprecated && struct_def.fixed)
    return Error("can't deprecate fields in a struct");

  auto cpp_type = field->attributes.Lookup("cpp_type");
  if (cpp_type) {
    if (!hash_name)
      return Error("cpp_type can only be used with a hashed field");
    /// forcing cpp_ptr_type to 'naked' if unset
    auto cpp_ptr_type = field->attributes.Lookup("cpp_ptr_type");
    if (!cpp_ptr_type) {
      auto val = new Value();
      val->type = cpp_type->type;
      val->constant = "naked";
      field->attributes.Add("cpp_ptr_type", val);
    }
  }

  field->shared = field->attributes.Lookup("shared") != nullptr;
  if (field->shared && field->value.type.base_type != BASE_TYPE_STRING)
    return Error("shared can only be defined on strings");

  auto field_native_custom_alloc =
      field->attributes.Lookup("native_custom_alloc");
  if (field_native_custom_alloc)
    return Error(
        "native_custom_alloc can only be used with a table or struct "
        "definition");

  field->native_inline = field->attributes.Lookup("native_inline") != nullptr;
  if (field->native_inline && !IsStruct(field->value.type) &&
      !IsVectorOfStruct(field->value.type) &&
      !IsVectorOfTable(field->value.type))
    return Error(
        "'native_inline' can only be defined on structs, vector of structs or "
        "vector of tables");

  auto nested = field->attributes.Lookup("nested_flatbuffer");
  if (nested) {
    if (nested->type.base_type != BASE_TYPE_STRING)
      return Error(
          "nested_flatbuffer attribute must be a string (the root type)");
    if (!IsVector(type.base_type) || type.element != BASE_TYPE_UCHAR)
      return Error(
          "nested_flatbuffer attribute may only apply to a vector of ubyte");
    // This will cause an error if the root type of the nested flatbuffer
    // wasn't defined elsewhere.
    field->nested_flatbuffer = LookupCreateStruct(nested->constant);
  }

  if (field->attributes.Lookup("flexbuffer")) {
    field->flexbuffer = true;
    uses_flexbuffers_ = true;
    if (type.base_type != BASE_TYPE_VECTOR || type.element != BASE_TYPE_UCHAR)
      return Error("flexbuffer attribute may only apply to a vector of ubyte");
  }

  if (typefield) {
    if (!IsScalar(typefield->value.type.base_type)) {
      // this is a union vector field
      typefield->presence = field->presence;
    }
    // If this field is a union, and it has a manually assigned id,
    // the automatically added type field should have an id as well (of N - 1).
    auto attr = field->attributes.Lookup("id");
    if (attr) {
      const auto &id_str = attr->constant;
      voffset_t id = 0;
      const auto done = !atot(id_str.c_str(), *this, &id).Check();
      if (done && id > 0) {
        auto val = new Value();
        val->type = attr->type;
        val->constant = NumToString(id - 1);
        typefield->attributes.Add("id", val);
      } else {
        return Error(
            "a union type effectively adds two fields with non-negative ids, "
            "its id must be that of the second field (the first field is "
            "the type field and not explicitly declared in the schema);\n"
            "field: " +
            field->name + ", id: " + id_str);
      }
    }
    // if this field is a union that is deprecated,
    // the automatically added type field should be deprecated as well
    if (field->deprecated) { typefield->deprecated = true; }
  }

  EXPECT(';');
  return NoError();
}

CheckedError Parser::ParseString(Value &val, bool use_string_pooling) {
  auto s = attribute_;
  EXPECT(kTokenStringConstant);
  if (use_string_pooling) {
    val.constant = NumToString(builder_.CreateSharedString(s).o);
  } else {
    val.constant = NumToString(builder_.CreateString(s).o);
  }
  return NoError();
}

CheckedError Parser::ParseComma() {
  if (!opts.protobuf_ascii_alike) EXPECT(',');
  return NoError();
}

CheckedError Parser::ParseAnyValue(Value &val, FieldDef *field,
                                   size_t parent_fieldn,
                                   const StructDef *parent_struct_def,
                                   size_t count, bool inside_vector) {
  switch (val.type.base_type) {
    case BASE_TYPE_UNION: {
      FLATBUFFERS_ASSERT(field);
      std::string constant;
      Vector<uint8_t> *vector_of_union_types = nullptr;
      // Find corresponding type field we may have already parsed.
      for (auto elem = field_stack_.rbegin() + count;
           elem != field_stack_.rbegin() + parent_fieldn + count; ++elem) {
        auto &type = elem->second->value.type;
        if (type.enum_def == val.type.enum_def) {
          if (inside_vector) {
            if (IsVector(type) && type.element == BASE_TYPE_UTYPE) {
              // Vector of union type field.
              uoffset_t offset;
              ECHECK(atot(elem->first.constant.c_str(), *this, &offset));
              vector_of_union_types = reinterpret_cast<Vector<uint8_t> *>(
                  builder_.GetCurrentBufferPointer() + builder_.GetSize() -
                  offset);
              break;
            }
          } else {
            if (type.base_type == BASE_TYPE_UTYPE) {
              // Union type field.
              constant = elem->first.constant;
              break;
            }
          }
        }
      }
      if (constant.empty() && !inside_vector) {
        // We haven't seen the type field yet. Sadly a lot of JSON writers
        // output these in alphabetical order, meaning it comes after this
        // value. So we scan past the value to find it, then come back here.
        // We currently don't do this for vectors of unions because the
        // scanning/serialization logic would get very complicated.
        auto type_name = field->name + UnionTypeFieldSuffix();
        FLATBUFFERS_ASSERT(parent_struct_def);
        auto type_field = parent_struct_def->fields.Lookup(type_name);
        FLATBUFFERS_ASSERT(type_field);  // Guaranteed by ParseField().
        // Remember where we are in the source file, so we can come back here.
        auto backup = *static_cast<ParserState *>(this);
        ECHECK(SkipAnyJsonValue());  // The table.
        ECHECK(ParseComma());
        auto next_name = attribute_;
        if (Is(kTokenStringConstant)) {
          NEXT();
        } else {
          EXPECT(kTokenIdentifier);
        }
        if (next_name == type_name) {
          EXPECT(':');
          ParseDepthGuard depth_guard(this);
          ECHECK(depth_guard.Check());
          Value type_val = type_field->value;
          ECHECK(ParseAnyValue(type_val, type_field, 0, nullptr, 0));
          constant = type_val.constant;
          // Got the information we needed, now rewind:
          *static_cast<ParserState *>(this) = backup;
        }
      }
      if (constant.empty() && !vector_of_union_types) {
        return Error("missing type field for this union value: " + field->name);
      }
      uint8_t enum_idx;
      if (vector_of_union_types) {
        if (vector_of_union_types->size() <= count)
          return Error(
              "union types vector smaller than union values vector for: " +
              field->name);
        enum_idx = vector_of_union_types->Get(static_cast<uoffset_t>(count));
      } else {
        ECHECK(atot(constant.c_str(), *this, &enum_idx));
      }
      auto enum_val = val.type.enum_def->ReverseLookup(enum_idx, true);
      if (!enum_val) return Error("illegal type id for: " + field->name);
      if (enum_val->union_type.base_type == BASE_TYPE_STRUCT) {
        ECHECK(ParseTable(*enum_val->union_type.struct_def, &val.constant,
                          nullptr));
        if (enum_val->union_type.struct_def->fixed) {
          // All BASE_TYPE_UNION values are offsets, so turn this into one.
          SerializeStruct(*enum_val->union_type.struct_def, val);
          builder_.ClearOffsets();
          val.constant = NumToString(builder_.GetSize());
        }
      } else if (IsString(enum_val->union_type)) {
        ECHECK(ParseString(val, field->shared));
      } else {
        FLATBUFFERS_ASSERT(false);
      }
      break;
    }
    case BASE_TYPE_STRUCT:
      ECHECK(ParseTable(*val.type.struct_def, &val.constant, nullptr));
      break;
    case BASE_TYPE_STRING: {
      ECHECK(ParseString(val, field->shared));
      break;
    }
    case BASE_TYPE_VECTOR64:
    case BASE_TYPE_VECTOR: {
      uoffset_t off;
      ECHECK(ParseVector(val.type, &off, field, parent_fieldn));
      val.constant = NumToString(off);
      break;
    }
    case BASE_TYPE_ARRAY: {
      ECHECK(ParseArray(val));
      break;
    }
    case BASE_TYPE_INT:
    case BASE_TYPE_UINT:
    case BASE_TYPE_LONG:
    case BASE_TYPE_ULONG: {
      if (field && field->attributes.Lookup("hash") &&
          (token_ == kTokenIdentifier || token_ == kTokenStringConstant)) {
        ECHECK(ParseHash(val, field));
      } else {
        ECHECK(ParseSingleValue(field ? &field->name : nullptr, val, false));
      }
      break;
    }
    default:
      ECHECK(ParseSingleValue(field ? &field->name : nullptr, val, false));
      break;
  }
  return NoError();
}

void Parser::SerializeStruct(const StructDef &struct_def, const Value &val) {
  SerializeStruct(builder_, struct_def, val);
}

void Parser::SerializeStruct(FlatBufferBuilder &builder,
                             const StructDef &struct_def, const Value &val) {
  FLATBUFFERS_ASSERT(val.constant.length() == struct_def.bytesize);
  builder.Align(struct_def.minalign);
  builder.PushBytes(reinterpret_cast<const uint8_t *>(val.constant.c_str()),
                    struct_def.bytesize);
  builder.AddStructOffset(val.offset, builder.GetSize());
}

template<typename F>
CheckedError Parser::ParseTableDelimiters(size_t &fieldn,
                                          const StructDef *struct_def, F body) {
  // We allow tables both as JSON object{ .. } with field names
  // or vector[..] with all fields in order
  char terminator = '}';
  bool is_nested_vector = struct_def && Is('[');
  if (is_nested_vector) {
    NEXT();
    terminator = ']';
  } else {
    EXPECT('{');
  }
  for (;;) {
    if ((!opts.strict_json || !fieldn) && Is(terminator)) break;
    std::string name;
    if (is_nested_vector) {
      if (fieldn >= struct_def->fields.vec.size()) {
        return Error("too many unnamed fields in nested array");
      }
      name = struct_def->fields.vec[fieldn]->name;
    } else {
      name = attribute_;
      if (Is(kTokenStringConstant)) {
        NEXT();
      } else {
        EXPECT(opts.strict_json ? kTokenStringConstant : kTokenIdentifier);
      }
      if (!opts.protobuf_ascii_alike || !(Is('{') || Is('['))) EXPECT(':');
    }
    ECHECK(body(name, fieldn, struct_def));
    if (Is(terminator)) break;
    ECHECK(ParseComma());
  }
  NEXT();
  if (is_nested_vector && fieldn != struct_def->fields.vec.size()) {
    return Error("wrong number of unnamed fields in table vector");
  }
  return NoError();
}

CheckedError Parser::ParseTable(const StructDef &struct_def, std::string *value,
                                uoffset_t *ovalue) {
  ParseDepthGuard depth_guard(this);
  ECHECK(depth_guard.Check());

  size_t fieldn_outer = 0;
  auto err = ParseTableDelimiters(
      fieldn_outer, &struct_def,
      [&](const std::string &name, size_t &fieldn,
          const StructDef *struct_def_inner) -> CheckedError {
        if (name == "$schema") {
          ECHECK(Expect(kTokenStringConstant));
          return NoError();
        }
        auto field = struct_def_inner->fields.Lookup(name);
        if (!field) {
          if (!opts.skip_unexpected_fields_in_json) {
            return Error("unknown field: " + name);
          } else {
            ECHECK(SkipAnyJsonValue());
          }
        } else {
          if (IsIdent("null") && !IsScalar(field->value.type.base_type)) {
            ECHECK(Next());  // Ignore this field.
          } else {
            Value val = field->value;
            if (field->flexbuffer) {
              flexbuffers::Builder builder(1024,
                                           flexbuffers::BUILDER_FLAG_SHARE_ALL);
              ECHECK(ParseFlexBufferValue(&builder));
              builder.Finish();
              // Force alignment for nested flexbuffer
              builder_.ForceVectorAlignment(builder.GetSize(), sizeof(uint8_t),
                                            sizeof(largest_scalar_t));
              auto off = builder_.CreateVector(builder.GetBuffer());
              val.constant = NumToString(off.o);
            } else if (field->nested_flatbuffer) {
              ECHECK(
                  ParseNestedFlatbuffer(val, field, fieldn, struct_def_inner));
            } else {
              ECHECK(ParseAnyValue(val, field, fieldn, struct_def_inner, 0));
            }
            // Hardcoded insertion-sort with error-check.
            // If fields are specified in order, then this loop exits
            // immediately.
            auto elem = field_stack_.rbegin();
            for (; elem != field_stack_.rbegin() + fieldn; ++elem) {
              auto existing_field = elem->second;
              if (existing_field == field)
                return Error("field set more than once: " + field->name);
              if (existing_field->value.offset < field->value.offset) break;
            }
            // Note: elem points to before the insertion point, thus .base()
            // points to the correct spot.
            field_stack_.insert(elem.base(), std::make_pair(val, field));
            fieldn++;
          }
        }
        return NoError();
      });
  ECHECK(err);

  // Check if all required fields are parsed.
  for (auto field_it = struct_def.fields.vec.begin();
       field_it != struct_def.fields.vec.end(); ++field_it) {
    auto required_field = *field_it;
    if (!required_field->IsRequired()) { continue; }
    bool found = false;
    for (auto pf_it = field_stack_.end() - fieldn_outer;
         pf_it != field_stack_.end(); ++pf_it) {
      auto parsed_field = pf_it->second;
      if (parsed_field == required_field) {
        found = true;
        break;
      }
    }
    if (!found) {
      return Error("required field is missing: " + required_field->name +
                   " in " + struct_def.name);
    }
  }

  if (struct_def.fixed && fieldn_outer != struct_def.fields.vec.size())
    return Error("struct: wrong number of initializers: " + struct_def.name);

  auto start = struct_def.fixed ? builder_.StartStruct(struct_def.minalign)
                                : builder_.StartTable();

  for (size_t size = struct_def.sortbysize ? sizeof(largest_scalar_t) : 1; size;
       size /= 2) {
    // Go through elements in reverse, since we're building the data backwards.
    // TODO(derekbailey): this doesn't work when there are Offset64 fields, as
    // those have to be built first. So this needs to be changed to iterate over
    // Offset64 then Offset32 fields.
    for (auto it = field_stack_.rbegin();
         it != field_stack_.rbegin() + fieldn_outer; ++it) {
      auto &field_value = it->first;
      auto field = it->second;
      if (!struct_def.sortbysize ||
          size == SizeOf(field_value.type.base_type)) {
        switch (field_value.type.base_type) {
          // clang-format off
          #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
            case BASE_TYPE_ ## ENUM: \
              builder_.Pad(field->padding); \
              if (struct_def.fixed) { \
                CTYPE val; \
                ECHECK(atot(field_value.constant.c_str(), *this, &val)); \
                builder_.PushElement(val); \
              } else { \
                if (field->IsScalarOptional()) { \
                  if (field_value.constant != "null") { \
                    CTYPE val; \
                    ECHECK(atot(field_value.constant.c_str(), *this, &val)); \
                    builder_.AddElement(field_value.offset, val); \
                  } \
                } else { \
                  CTYPE val, valdef; \
                  ECHECK(atot(field_value.constant.c_str(), *this, &val)); \
                  ECHECK(atot(field->value.constant.c_str(), *this, &valdef)); \
                  builder_.AddElement(field_value.offset, val, valdef); \
                } \
              } \
              break;
            FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD)
          #undef FLATBUFFERS_TD
          #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
            case BASE_TYPE_ ## ENUM: \
              builder_.Pad(field->padding); \
              if (IsStruct(field->value.type)) { \
                SerializeStruct(*field->value.type.struct_def, field_value); \
              } else { \
                /* Special case for fields that use 64-bit addressing */ \
                if(field->offset64) { \
                  Offset64<void> offset; \
                  ECHECK(atot(field_value.constant.c_str(), *this, &offset)); \
                  builder_.AddOffset(field_value.offset, offset); \
                } else { \
                  CTYPE val; \
                  ECHECK(atot(field_value.constant.c_str(), *this, &val)); \
                  builder_.AddOffset(field_value.offset, val); \
                } \
              } \
              break;
            FLATBUFFERS_GEN_TYPES_POINTER(FLATBUFFERS_TD)
          #undef FLATBUFFERS_TD
            case BASE_TYPE_ARRAY:
              builder_.Pad(field->padding);
              builder_.PushBytes(
                reinterpret_cast<const uint8_t*>(field_value.constant.c_str()),
                InlineSize(field_value.type));
              break;
            // clang-format on
        }
      }
    }
  }
  for (size_t i = 0; i < fieldn_outer; i++) field_stack_.pop_back();

  if (struct_def.fixed) {
    builder_.ClearOffsets();
    builder_.EndStruct();
    FLATBUFFERS_ASSERT(value);
    // Temporarily store this struct in the value string, since it is to
    // be serialized in-place elsewhere.
    value->assign(
        reinterpret_cast<const char *>(builder_.GetCurrentBufferPointer()),
        struct_def.bytesize);
    builder_.PopBytes(struct_def.bytesize);
    FLATBUFFERS_ASSERT(!ovalue);
  } else {
    auto val = builder_.EndTable(start);
    if (ovalue) *ovalue = val;
    if (value) *value = NumToString(val);
  }
  return NoError();
}

template<typename F>
CheckedError Parser::ParseVectorDelimiters(size_t &count, F body) {
  EXPECT('[');
  for (;;) {
    if ((!opts.strict_json || !count) && Is(']')) break;
    ECHECK(body(count));
    count++;
    if (Is(']')) break;
    ECHECK(ParseComma());
  }
  NEXT();
  return NoError();
}

CheckedError Parser::ParseAlignAttribute(const std::string &align_constant,
                                         size_t min_align, size_t *align) {
  // Use uint8_t to avoid problems with size_t==`unsigned long` on LP64.
  uint8_t align_value;
  if (StringToNumber(align_constant.c_str(), &align_value) &&
      VerifyAlignmentRequirements(static_cast<size_t>(align_value),
                                  min_align)) {
    *align = align_value;
    return NoError();
  }
  return Error("unexpected force_align value '" + align_constant +
               "', alignment must be a power of two integer ranging from the "
               "type\'s natural alignment " +
               NumToString(min_align) + " to " +
               NumToString(FLATBUFFERS_MAX_ALIGNMENT));
}

CheckedError Parser::ParseVector(const Type &vector_type, uoffset_t *ovalue,
                                 FieldDef *field, size_t fieldn) {
  Type type = vector_type.VectorType();
  size_t count = 0;
  auto err = ParseVectorDelimiters(count, [&](size_t &) -> CheckedError {
    Value val;
    val.type = type;
    ECHECK(ParseAnyValue(val, field, fieldn, nullptr, count, true));
    field_stack_.push_back(std::make_pair(val, nullptr));
    return NoError();
  });
  ECHECK(err);

  const size_t alignment = InlineAlignment(type);
  const size_t len = count * InlineSize(type) / InlineAlignment(type);
  const size_t elemsize = InlineAlignment(type);
  const auto force_align = field->attributes.Lookup("force_align");
  if (force_align) {
    size_t align;
    ECHECK(ParseAlignAttribute(force_align->constant, 1, &align));
    if (align > 1) { builder_.ForceVectorAlignment(len, elemsize, align); }
  }

  // TODO Fix using element alignment as size (`elemsize`)!
  if (vector_type.base_type == BASE_TYPE_VECTOR64) {
    // TODO(derekbailey): this requires a 64-bit builder.
    // builder_.StartVector<Offset64, uoffset64_t>(len, elemsize, alignment);
    builder_.StartVector(len, elemsize, alignment);
  } else {
    builder_.StartVector(len, elemsize, alignment);
  }
  for (size_t i = 0; i < count; i++) {
    // start at the back, since we're building the data backwards.
    auto &val = field_stack_.back().first;
    switch (val.type.base_type) {
      // clang-format off
      #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE,...) \
        case BASE_TYPE_ ## ENUM: \
          if (IsStruct(val.type)) SerializeStruct(*val.type.struct_def, val); \
          else { \
             CTYPE elem; \
             ECHECK(atot(val.constant.c_str(), *this, &elem)); \
             builder_.PushElement(elem); \
          } \
          break;
        FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
      #undef FLATBUFFERS_TD
      // clang-format on
    }
    field_stack_.pop_back();
  }

  builder_.ClearOffsets();
  if (vector_type.base_type == BASE_TYPE_VECTOR64) {
    *ovalue = builder_.EndVector<uoffset64_t>(count);
  } else {
    *ovalue = builder_.EndVector(count);
  }

  if (type.base_type == BASE_TYPE_STRUCT && type.struct_def->has_key) {
    // We should sort this vector. Find the key first.
    const FieldDef *key = nullptr;
    for (auto it = type.struct_def->fields.vec.begin();
         it != type.struct_def->fields.vec.end(); ++it) {
      if ((*it)->key) {
        key = (*it);
        break;
      }
    }
    FLATBUFFERS_ASSERT(key);
    // Now sort it.
    // We can't use std::sort because for structs the size is not known at
    // compile time, and for tables our iterators dereference offsets, so can't
    // be used to swap elements.
    // And we can't use C qsort either, since that would force use to use
    // globals, making parsing thread-unsafe.
    // So for now, we use SimpleQsort above.
    // TODO: replace with something better, preferably not recursive.

    if (type.struct_def->fixed) {
      const voffset_t offset = key->value.offset;
      const size_t struct_size = type.struct_def->bytesize;
      auto v =
          reinterpret_cast<VectorOfAny *>(builder_.GetCurrentBufferPointer());
      SimpleQsort<uint8_t>(
          v->Data(), v->Data() + v->size() * type.struct_def->bytesize,
          type.struct_def->bytesize,
          [offset, key](const uint8_t *a, const uint8_t *b) -> bool {
            return CompareSerializedScalars(a + offset, b + offset, *key);
          },
          [struct_size](uint8_t *a, uint8_t *b) {
            // FIXME: faster?
            for (size_t i = 0; i < struct_size; i++) { std::swap(a[i], b[i]); }
          });
    } else {
      auto v = reinterpret_cast<Vector<Offset<Table>> *>(
          builder_.GetCurrentBufferPointer());
      // Here also can't use std::sort. We do have an iterator type for it,
      // but it is non-standard as it will dereference the offsets, and thus
      // can't be used to swap elements.
      if (key->value.type.base_type == BASE_TYPE_STRING) {
        SimpleQsort<Offset<Table>>(
            v->data(), v->data() + v->size(), 1,
            [key](const Offset<Table> *_a, const Offset<Table> *_b) -> bool {
              return CompareTablesByStringKey(_a, _b, *key);
            },
            SwapSerializedTables);
      } else {
        SimpleQsort<Offset<Table>>(
            v->data(), v->data() + v->size(), 1,
            [key](const Offset<Table> *_a, const Offset<Table> *_b) -> bool {
              return CompareTablesByScalarKey(_a, _b, *key);
            },
            SwapSerializedTables);
      }
    }
  }
  return NoError();
}

CheckedError Parser::ParseArray(Value &array) {
  std::vector<Value> stack;
  FlatBufferBuilder builder;
  const auto &type = array.type.VectorType();
  auto length = array.type.fixed_length;
  size_t count = 0;
  auto err = ParseVectorDelimiters(count, [&](size_t &) -> CheckedError {
    stack.emplace_back(Value());
    auto &val = stack.back();
    val.type = type;
    if (IsStruct(type)) {
      ECHECK(ParseTable(*val.type.struct_def, &val.constant, nullptr));
    } else {
      ECHECK(ParseSingleValue(nullptr, val, false));
    }
    return NoError();
  });
  ECHECK(err);
  if (length != count) return Error("Fixed-length array size is incorrect.");

  for (auto it = stack.rbegin(); it != stack.rend(); ++it) {
    auto &val = *it;
    // clang-format off
    switch (val.type.base_type) {
      #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
        case BASE_TYPE_ ## ENUM: \
          if (IsStruct(val.type)) { \
            SerializeStruct(builder, *val.type.struct_def, val); \
          } else { \
            CTYPE elem; \
            ECHECK(atot(val.constant.c_str(), *this, &elem)); \
            builder.PushElement(elem); \
          } \
        break;
        FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
      #undef FLATBUFFERS_TD
      default: FLATBUFFERS_ASSERT(0);
    }
    // clang-format on
  }

  array.constant.assign(
      reinterpret_cast<const char *>(builder.GetCurrentBufferPointer()),
      InlineSize(array.type));
  return NoError();
}

CheckedError Parser::ParseNestedFlatbuffer(Value &val, FieldDef *field,
                                           size_t fieldn,
                                           const StructDef *parent_struct_def) {
  if (token_ == '[') {  // backwards compat for 'legacy' ubyte buffers
    if (opts.json_nested_legacy_flatbuffers) {
      ECHECK(ParseAnyValue(val, field, fieldn, parent_struct_def, 0));
    } else {
      return Error(
          "cannot parse nested_flatbuffer as bytes unless"
          " --json-nested-bytes is set");
    }
  } else {
    auto cursor_at_value_begin = cursor_;
    ECHECK(SkipAnyJsonValue());
    std::string substring(cursor_at_value_begin - 1, cursor_ - 1);

    // Create and initialize new parser
    Parser nested_parser;
    FLATBUFFERS_ASSERT(field->nested_flatbuffer);
    nested_parser.root_struct_def_ = field->nested_flatbuffer;
    nested_parser.enums_ = enums_;
    nested_parser.opts = opts;
    nested_parser.uses_flexbuffers_ = uses_flexbuffers_;
    nested_parser.parse_depth_counter_ = parse_depth_counter_;
    // Parse JSON substring into new flatbuffer builder using nested_parser
    bool ok = nested_parser.Parse(substring.c_str(), nullptr, nullptr);

    // Clean nested_parser to avoid deleting the elements in
    // the SymbolTables on destruction
    nested_parser.enums_.dict.clear();
    nested_parser.enums_.vec.clear();

    if (!ok) { ECHECK(Error(nested_parser.error_)); }
    // Force alignment for nested flatbuffer
    builder_.ForceVectorAlignment(
        nested_parser.builder_.GetSize(), sizeof(uint8_t),
        nested_parser.builder_.GetBufferMinAlignment());

    auto off = builder_.CreateVector(nested_parser.builder_.GetBufferPointer(),
                                     nested_parser.builder_.GetSize());
    val.constant = NumToString(off.o);
  }
  return NoError();
}

CheckedError Parser::ParseMetaData(SymbolTable<Value> *attributes) {
  if (Is('(')) {
    NEXT();
    for (;;) {
      auto name = attribute_;
      if (false == (Is(kTokenIdentifier) || Is(kTokenStringConstant)))
        return Error("attribute name must be either identifier or string: " +
                     name);
      if (known_attributes_.find(name) == known_attributes_.end())
        return Error("user define attributes must be declared before use: " +
                     name);
      NEXT();
      auto e = new Value();
      if (attributes->Add(name, e)) Warning("attribute already found: " + name);
      if (Is(':')) {
        NEXT();
        ECHECK(ParseSingleValue(&name, *e, true));
      }
      if (Is(')')) {
        NEXT();
        break;
      }
      EXPECT(',');
    }
  }
  return NoError();
}

CheckedError Parser::ParseEnumFromString(const Type &type,
                                         std::string *result) {
  const auto base_type =
      type.enum_def ? type.enum_def->underlying_type.base_type : type.base_type;
  if (!IsInteger(base_type)) return Error("not a valid value for this field");
  uint64_t u64 = 0;
  for (size_t pos = 0; pos != std::string::npos;) {
    const auto delim = attribute_.find_first_of(' ', pos);
    const auto last = (std::string::npos == delim);
    auto word = attribute_.substr(pos, !last ? delim - pos : std::string::npos);
    pos = !last ? delim + 1 : std::string::npos;
    const EnumVal *ev = nullptr;
    if (type.enum_def) {
      ev = type.enum_def->Lookup(word);
    } else {
      auto dot = word.find_first_of('.');
      if (std::string::npos == dot)
        return Error("enum values need to be qualified by an enum type");
      auto enum_def_str = word.substr(0, dot);
      const auto enum_def = LookupEnum(enum_def_str);
      if (!enum_def) return Error("unknown enum: " + enum_def_str);
      auto enum_val_str = word.substr(dot + 1);
      ev = enum_def->Lookup(enum_val_str);
    }
    if (!ev) return Error("unknown enum value: " + word);
    u64 |= ev->GetAsUInt64();
  }
  *result = IsUnsigned(base_type) ? NumToString(u64)
                                  : NumToString(static_cast<int64_t>(u64));
  return NoError();
}

CheckedError Parser::ParseHash(Value &e, FieldDef *field) {
  FLATBUFFERS_ASSERT(field);
  Value *hash_name = field->attributes.Lookup("hash");
  switch (e.type.base_type) {
    case BASE_TYPE_SHORT: {
      auto hash = FindHashFunction16(hash_name->constant.c_str());
      int16_t hashed_value = static_cast<int16_t>(hash(attribute_.c_str()));
      e.constant = NumToString(hashed_value);
      break;
    }
    case BASE_TYPE_USHORT: {
      auto hash = FindHashFunction16(hash_name->constant.c_str());
      uint16_t hashed_value = hash(attribute_.c_str());
      e.constant = NumToString(hashed_value);
      break;
    }
    case BASE_TYPE_INT: {
      auto hash = FindHashFunction32(hash_name->constant.c_str());
      int32_t hashed_value = static_cast<int32_t>(hash(attribute_.c_str()));
      e.constant = NumToString(hashed_value);
      break;
    }
    case BASE_TYPE_UINT: {
      auto hash = FindHashFunction32(hash_name->constant.c_str());
      uint32_t hashed_value = hash(attribute_.c_str());
      e.constant = NumToString(hashed_value);
      break;
    }
    case BASE_TYPE_LONG: {
      auto hash = FindHashFunction64(hash_name->constant.c_str());
      int64_t hashed_value = static_cast<int64_t>(hash(attribute_.c_str()));
      e.constant = NumToString(hashed_value);
      break;
    }
    case BASE_TYPE_ULONG: {
      auto hash = FindHashFunction64(hash_name->constant.c_str());
      uint64_t hashed_value = hash(attribute_.c_str());
      e.constant = NumToString(hashed_value);
      break;
    }
    default: FLATBUFFERS_ASSERT(0);
  }
  NEXT();
  return NoError();
}

CheckedError Parser::TokenError() {
  return Error("cannot parse value starting with: " + TokenToStringId(token_));
}

CheckedError Parser::ParseFunction(const std::string *name, Value &e) {
  ParseDepthGuard depth_guard(this);
  ECHECK(depth_guard.Check());

  // Copy name, attribute will be changed on NEXT().
  const auto functionname = attribute_;
  if (!IsFloat(e.type.base_type)) {
    return Error(functionname + ": type of argument mismatch, expecting: " +
                 TypeName(BASE_TYPE_DOUBLE) +
                 ", found: " + TypeName(e.type.base_type) +
                 ", name: " + (name ? *name : "") + ", value: " + e.constant);
  }
  NEXT();
  EXPECT('(');
  ECHECK(ParseSingleValue(name, e, false));
  EXPECT(')');
  // calculate with double precision
  double x, y = 0.0;
  ECHECK(atot(e.constant.c_str(), *this, &x));
  // clang-format off
  auto func_match = false;
  #define FLATBUFFERS_FN_DOUBLE(name, op) \
    if (!func_match && functionname == name) { y = op; func_match = true; }
  FLATBUFFERS_FN_DOUBLE("deg", x / kPi * 180);
  FLATBUFFERS_FN_DOUBLE("rad", x * kPi / 180);
  FLATBUFFERS_FN_DOUBLE("sin", sin(x));
  FLATBUFFERS_FN_DOUBLE("cos", cos(x));
  FLATBUFFERS_FN_DOUBLE("tan", tan(x));
  FLATBUFFERS_FN_DOUBLE("asin", asin(x));
  FLATBUFFERS_FN_DOUBLE("acos", acos(x));
  FLATBUFFERS_FN_DOUBLE("atan", atan(x));
  // TODO(wvo): add more useful conversion functions here.
  #undef FLATBUFFERS_FN_DOUBLE
  // clang-format on
  if (true != func_match) {
    return Error(std::string("Unknown conversion function: ") + functionname +
                 ", field name: " + (name ? *name : "") +
                 ", value: " + e.constant);
  }
  e.constant = NumToString(y);
  return NoError();
}

CheckedError Parser::TryTypedValue(const std::string *name, int dtoken,
                                   bool check, Value &e, BaseType req,
                                   bool *destmatch) {
  FLATBUFFERS_ASSERT(*destmatch == false && dtoken == token_);
  *destmatch = true;
  e.constant = attribute_;
  // Check token match
  if (!check) {
    if (e.type.base_type == BASE_TYPE_NONE) {
      e.type.base_type = req;
    } else {
      return Error(std::string("type mismatch: expecting: ") +
                   TypeName(e.type.base_type) + ", found: " + TypeName(req) +
                   ", name: " + (name ? *name : "") + ", value: " + e.constant);
    }
  }
  // The exponent suffix of hexadecimal float-point number is mandatory.
  // A hex-integer constant is forbidden as an initializer of float number.
  if ((kTokenFloatConstant != dtoken) && IsFloat(e.type.base_type)) {
    const auto &s = e.constant;
    const auto k = s.find_first_of("0123456789.");
    if ((std::string::npos != k) && (s.length() > (k + 1)) &&
        (s[k] == '0' && is_alpha_char(s[k + 1], 'X')) &&
        (std::string::npos == s.find_first_of("pP", k + 2))) {
      return Error(
          "invalid number, the exponent suffix of hexadecimal "
          "floating-point literals is mandatory: \"" +
          s + "\"");
    }
  }
  NEXT();
  return NoError();
}

CheckedError Parser::ParseSingleValue(const std::string *name, Value &e,
                                      bool check_now) {
  if (token_ == '+' || token_ == '-') {
    const char sign = static_cast<char>(token_);
    // Get an indentifier: NAN, INF, or function name like cos/sin/deg.
    NEXT();
    if (token_ != kTokenIdentifier) return Error("constant name expected");
    attribute_.insert(size_t(0), size_t(1), sign);
  }

  const auto in_type = e.type.base_type;
  const auto is_tok_ident = (token_ == kTokenIdentifier);
  const auto is_tok_string = (token_ == kTokenStringConstant);

  // First see if this could be a conversion function.
  if (is_tok_ident && *cursor_ == '(') { return ParseFunction(name, e); }

  // clang-format off
  auto match = false;

  #define IF_ECHECK_(force, dtoken, check, req)    \
    if (!match && ((dtoken) == token_) && ((check) || IsConstTrue(force))) \
      ECHECK(TryTypedValue(name, dtoken, check, e, req, &match))
  #define TRY_ECHECK(dtoken, check, req) IF_ECHECK_(false, dtoken, check, req)
  #define FORCE_ECHECK(dtoken, check, req) IF_ECHECK_(true, dtoken, check, req)
  // clang-format on

  if (is_tok_ident || is_tok_string) {
    const auto kTokenStringOrIdent = token_;
    // The string type is a most probable type, check it first.
    TRY_ECHECK(kTokenStringConstant, in_type == BASE_TYPE_STRING,
               BASE_TYPE_STRING);

    // avoid escaped and non-ascii in the string
    if (!match && is_tok_string && IsScalar(in_type) &&
        !attr_is_trivial_ascii_string_) {
      return Error(
          std::string("type mismatch or invalid value, an initializer of "
                      "non-string field must be trivial ASCII string: type: ") +
          TypeName(in_type) + ", name: " + (name ? *name : "") +
          ", value: " + attribute_);
    }

    // A boolean as true/false. Boolean as Integer check below.
    if (!match && IsBool(in_type)) {
      auto is_true = attribute_ == "true";
      if (is_true || attribute_ == "false") {
        attribute_ = is_true ? "1" : "0";
        // accepts both kTokenStringConstant and kTokenIdentifier
        TRY_ECHECK(kTokenStringOrIdent, IsBool(in_type), BASE_TYPE_BOOL);
      }
    }
    // Check for optional scalars.
    if (!match && IsScalar(in_type) && attribute_ == "null") {
      e.constant = "null";
      NEXT();
      match = true;
    }
    // Check if this could be a string/identifier enum value.
    // Enum can have only true integer base type.
    if (!match && IsInteger(in_type) && !IsBool(in_type) &&
        IsIdentifierStart(*attribute_.c_str())) {
      ECHECK(ParseEnumFromString(e.type, &e.constant));
      NEXT();
      match = true;
    }
    // Parse a float/integer number from the string.
    // A "scalar-in-string" value needs extra checks.
    if (!match && is_tok_string && IsScalar(in_type)) {
      // Strip trailing whitespaces from attribute_.
      auto last_non_ws = attribute_.find_last_not_of(' ');
      if (std::string::npos != last_non_ws) attribute_.resize(last_non_ws + 1);
      if (IsFloat(e.type.base_type)) {
        // The functions strtod() and strtof() accept both 'nan' and
        // 'nan(number)' literals. While 'nan(number)' is rejected by the parser
        // as an unsupported function if is_tok_ident is true.
        if (attribute_.find_last_of(')') != std::string::npos) {
          return Error("invalid number: " + attribute_);
        }
      }
    }
    // Float numbers or nan, inf, pi, etc.
    TRY_ECHECK(kTokenStringOrIdent, IsFloat(in_type), BASE_TYPE_FLOAT);
    // An integer constant in string.
    TRY_ECHECK(kTokenStringOrIdent, IsInteger(in_type), BASE_TYPE_INT);
    // Unknown tokens will be interpreted as string type.
    // An attribute value may be a scalar or string constant.
    FORCE_ECHECK(kTokenStringConstant, in_type == BASE_TYPE_STRING,
                 BASE_TYPE_STRING);
  } else {
    // Try a float number.
    TRY_ECHECK(kTokenFloatConstant, IsFloat(in_type), BASE_TYPE_FLOAT);
    // Integer token can init any scalar (integer of float).
    FORCE_ECHECK(kTokenIntegerConstant, IsScalar(in_type), BASE_TYPE_INT);
  }
  // Match empty vectors for default-empty-vectors.
  if (!match && IsVector(e.type) && token_ == '[') {
    NEXT();
    if (token_ != ']') { return Error("Expected `]` in vector default"); }
    NEXT();
    match = true;
    e.constant = "[]";
  }

#undef FORCE_ECHECK
#undef TRY_ECHECK
#undef IF_ECHECK_

  if (!match) {
    std::string msg;
    msg += "Cannot assign token starting with '" + TokenToStringId(token_) +
           "' to value of <" + std::string(TypeName(in_type)) + "> type.";
    return Error(msg);
  }
  const auto match_type = e.type.base_type;  // may differ from in_type
  // The check_now flag must be true when parse a fbs-schema.
  // This flag forces to check default scalar values or metadata of field.
  // For JSON parser the flag should be false.
  // If it is set for JSON each value will be checked twice (see ParseTable).
  // Special case 'null' since atot can't handle that.
  if (check_now && IsScalar(match_type) && e.constant != "null") {
    // clang-format off
    switch (match_type) {
    #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
      case BASE_TYPE_ ## ENUM: {\
          CTYPE val; \
          ECHECK(atot(e.constant.c_str(), *this, &val)); \
          SingleValueRepack(e, val); \
        break; }
    FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD)
    #undef FLATBUFFERS_TD
    default: break;
    }
    // clang-format on
  }
  return NoError();
}

StructDef *Parser::LookupCreateStruct(const std::string &name,
                                      bool create_if_new, bool definition) {
  std::string qualified_name = current_namespace_->GetFullyQualifiedName(name);
  // See if it exists pre-declared by an unqualified use.
  auto struct_def = LookupStruct(name);
  if (struct_def && struct_def->predecl) {
    if (definition) {
      // Make sure it has the current namespace, and is registered under its
      // qualified name.
      struct_def->defined_namespace = current_namespace_;
      structs_.Move(name, qualified_name);
    }
    return struct_def;
  }
  // See if it exists pre-declared by an qualified use.
  struct_def = LookupStruct(qualified_name);
  if (struct_def && struct_def->predecl) {
    if (definition) {
      // Make sure it has the current namespace.
      struct_def->defined_namespace = current_namespace_;
    }
    return struct_def;
  }
  if (!definition && !struct_def) {
    struct_def = LookupStructThruParentNamespaces(name);
  }
  if (!struct_def && create_if_new) {
    struct_def = new StructDef();
    if (definition) {
      structs_.Add(qualified_name, struct_def);
      struct_def->name = name;
      struct_def->defined_namespace = current_namespace_;
    } else {
      // Not a definition.
      // Rather than failing, we create a "pre declared" StructDef, due to
      // circular references, and check for errors at the end of parsing.
      // It is defined in the current namespace, as the best guess what the
      // final namespace will be.
      structs_.Add(name, struct_def);
      struct_def->name = name;
      struct_def->defined_namespace = current_namespace_;
      struct_def->original_location.reset(
          new std::string(file_being_parsed_ + ":" + NumToString(line_)));
    }
  }
  return struct_def;
}

const EnumVal *EnumDef::MinValue() const {
  return vals.vec.empty() ? nullptr : vals.vec.front();
}
const EnumVal *EnumDef::MaxValue() const {
  return vals.vec.empty() ? nullptr : vals.vec.back();
}

uint64_t EnumDef::Distance(const EnumVal *v1, const EnumVal *v2) const {
  return IsUInt64() ? EnumDistanceImpl(v1->GetAsUInt64(), v2->GetAsUInt64())
                    : EnumDistanceImpl(v1->GetAsInt64(), v2->GetAsInt64());
}

std::string EnumDef::AllFlags() const {
  FLATBUFFERS_ASSERT(attributes.Lookup("bit_flags"));
  uint64_t u64 = 0;
  for (auto it = Vals().begin(); it != Vals().end(); ++it) {
    u64 |= (*it)->GetAsUInt64();
  }
  return IsUInt64() ? NumToString(u64) : NumToString(static_cast<int64_t>(u64));
}

EnumVal *EnumDef::ReverseLookup(int64_t enum_idx,
                                bool skip_union_default) const {
  auto skip_first = static_cast<int>(is_union && skip_union_default);
  for (auto it = Vals().begin() + skip_first; it != Vals().end(); ++it) {
    if ((*it)->GetAsInt64() == enum_idx) { return *it; }
  }
  return nullptr;
}

EnumVal *EnumDef::FindByValue(const std::string &constant) const {
  int64_t i64;
  auto done = false;
  if (IsUInt64()) {
    uint64_t u64;  // avoid reinterpret_cast of pointers
    done = StringToNumber(constant.c_str(), &u64);
    i64 = static_cast<int64_t>(u64);
  } else {
    done = StringToNumber(constant.c_str(), &i64);
  }
  FLATBUFFERS_ASSERT(done);
  if (!done) return nullptr;
  return ReverseLookup(i64, false);
}

void EnumDef::SortByValue() {
  auto &v = vals.vec;
  if (IsUInt64())
    std::sort(v.begin(), v.end(), [](const EnumVal *e1, const EnumVal *e2) {
      if (e1->GetAsUInt64() == e2->GetAsUInt64()) {
        return e1->name < e2->name;
      }
      return e1->GetAsUInt64() < e2->GetAsUInt64();
    });
  else
    std::sort(v.begin(), v.end(), [](const EnumVal *e1, const EnumVal *e2) {
      if (e1->GetAsInt64() == e2->GetAsInt64()) { return e1->name < e2->name; }
      return e1->GetAsInt64() < e2->GetAsInt64();
    });
}

void EnumDef::RemoveDuplicates() {
  // This method depends form SymbolTable implementation!
  // 1) vals.vec - owner (raw pointer)
  // 2) vals.dict - access map
  auto first = vals.vec.begin();
  auto last = vals.vec.end();
  if (first == last) return;
  auto result = first;
  while (++first != last) {
    if ((*result)->value != (*first)->value) {
      *(++result) = *first;
    } else {
      auto ev = *first;
      for (auto it = vals.dict.begin(); it != vals.dict.end(); ++it) {
        if (it->second == ev) it->second = *result;  // reassign
      }
      delete ev;  // delete enum value
      *first = nullptr;
    }
  }
  vals.vec.erase(++result, last);
}

template<typename T> void EnumDef::ChangeEnumValue(EnumVal *ev, T new_value) {
  ev->value = static_cast<int64_t>(new_value);
}

namespace EnumHelper {
template<BaseType E> struct EnumValType {
  typedef int64_t type;
};
template<> struct EnumValType<BASE_TYPE_ULONG> {
  typedef uint64_t type;
};
}  // namespace EnumHelper

struct EnumValBuilder {
  EnumVal *CreateEnumerator(const std::string &ev_name) {
    FLATBUFFERS_ASSERT(!temp);
    auto first = enum_def.vals.vec.empty();
    user_value = first;
    temp = new EnumVal(ev_name, first ? 0 : enum_def.vals.vec.back()->value);
    return temp;
  }

  EnumVal *CreateEnumerator(const std::string &ev_name, int64_t val) {
    FLATBUFFERS_ASSERT(!temp);
    user_value = true;
    temp = new EnumVal(ev_name, val);
    return temp;
  }

  FLATBUFFERS_CHECKED_ERROR AcceptEnumerator(const std::string &name) {
    FLATBUFFERS_ASSERT(temp);
    ECHECK(ValidateValue(&temp->value, false == user_value));
    FLATBUFFERS_ASSERT((temp->union_type.enum_def == nullptr) ||
                       (temp->union_type.enum_def == &enum_def));
    auto not_unique = enum_def.vals.Add(name, temp);
    temp = nullptr;
    if (not_unique) return parser.Error("enum value already exists: " + name);
    return NoError();
  }

  FLATBUFFERS_CHECKED_ERROR AcceptEnumerator() {
    return AcceptEnumerator(temp->name);
  }

  FLATBUFFERS_CHECKED_ERROR AssignEnumeratorValue(const std::string &value) {
    user_value = true;
    auto fit = false;
    if (enum_def.IsUInt64()) {
      uint64_t u64;
      fit = StringToNumber(value.c_str(), &u64);
      temp->value = static_cast<int64_t>(u64);  // well-defined since C++20.
    } else {
      int64_t i64;
      fit = StringToNumber(value.c_str(), &i64);
      temp->value = i64;
    }
    if (!fit) return parser.Error("enum value does not fit, \"" + value + "\"");
    return NoError();
  }

  template<BaseType E, typename CTYPE>
  inline FLATBUFFERS_CHECKED_ERROR ValidateImpl(int64_t *ev, int m) {
    typedef typename EnumHelper::EnumValType<E>::type T;  // int64_t or uint64_t
    static_assert(sizeof(T) == sizeof(int64_t), "invalid EnumValType");
    const auto v = static_cast<T>(*ev);
    auto up = static_cast<T>((flatbuffers::numeric_limits<CTYPE>::max)());
    auto dn = static_cast<T>((flatbuffers::numeric_limits<CTYPE>::lowest)());
    if (v < dn || v > (up - m)) {
      return parser.Error("enum value does not fit, \"" + NumToString(v) +
                          (m ? " + 1\"" : "\"") + " out of " +
                          TypeToIntervalString<CTYPE>());
    }
    *ev = static_cast<int64_t>(v + m);  // well-defined since C++20.
    return NoError();
  }

  FLATBUFFERS_CHECKED_ERROR ValidateValue(int64_t *ev, bool next) {
    // clang-format off
    switch (enum_def.underlying_type.base_type) {
    #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...)                   \
      case BASE_TYPE_##ENUM: {                                          \
        if (!IsInteger(BASE_TYPE_##ENUM)) break;                        \
        return ValidateImpl<BASE_TYPE_##ENUM, CTYPE>(ev, next ? 1 : 0); \
      }
      FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD)
    #undef FLATBUFFERS_TD
    default: break;
    }
    // clang-format on
    return parser.Error("fatal: invalid enum underlying type");
  }

  EnumValBuilder(Parser &_parser, EnumDef &_enum_def)
      : parser(_parser),
        enum_def(_enum_def),
        temp(nullptr),
        user_value(false) {}

  ~EnumValBuilder() { delete temp; }

  Parser &parser;
  EnumDef &enum_def;
  EnumVal *temp;
  bool user_value;
};

CheckedError Parser::ParseEnum(const bool is_union, EnumDef **dest,
                               const char *filename) {
  std::vector<std::string> enum_comment = doc_comment_;
  NEXT();
  std::string enum_name = attribute_;
  EXPECT(kTokenIdentifier);
  EnumDef *enum_def;
  ECHECK(StartEnum(enum_name, is_union, &enum_def));
  if (filename != nullptr && !opts.project_root.empty()) {
    enum_def->declaration_file =
        &GetPooledString(RelativeToRootPath(opts.project_root, filename));
  }
  enum_def->doc_comment = enum_comment;
  if (!opts.proto_mode) {
    // Give specialized error message, since this type spec used to
    // be optional in the first FlatBuffers release.
    bool explicit_underlying_type = false;
    if (!Is(':')) {
      // Enum is forced to have an explicit underlying type in declaration.
      if (!is_union) {
        return Error(
            "must specify the underlying integer type for this"
            " enum (e.g. \': short\', which was the default).");
      }
    } else {
      // Union underlying type is only supported for cpp
      if (is_union && !SupportsUnionUnderlyingType()) {
        return Error(
            "Underlying type for union is not yet supported in at least one of "
            "the specified programming languages.");
      }
      NEXT();
      explicit_underlying_type = true;
    }

    if (explicit_underlying_type) {
      // Specify the integer type underlying this enum.
      ECHECK(ParseType(enum_def->underlying_type));
      if (!IsInteger(enum_def->underlying_type.base_type) || IsBool(enum_def->underlying_type.base_type)) {
        return Error("underlying " + std::string(is_union ? "union" : "enum") + "type must be integral");
      }
        
      // Make this type refer back to the enum it was derived from.
      enum_def->underlying_type.enum_def = enum_def;
    }

  }
  ECHECK(ParseMetaData(&enum_def->attributes));
  const auto underlying_type = enum_def->underlying_type.base_type;
  if (enum_def->attributes.Lookup("bit_flags") &&
      !IsUnsigned(underlying_type)) {
    // todo: Convert to the Error in the future?
    Warning("underlying type of bit_flags enum must be unsigned");
  }
  if (enum_def->attributes.Lookup("force_align")) {
    return Error("`force_align` is not a valid attribute for Enums. ");
  }
  EnumValBuilder evb(*this, *enum_def);
  EXPECT('{');
  // A lot of code generatos expect that an enum is not-empty.
  if ((is_union || Is('}')) && !opts.proto_mode) {
    evb.CreateEnumerator("NONE");
    ECHECK(evb.AcceptEnumerator());
  }
  std::set<std::pair<BaseType, StructDef *>> union_types;
  while (!Is('}')) {
    if (opts.proto_mode && attribute_ == "option") {
      ECHECK(ParseProtoOption());
    } else {
      auto &ev = *evb.CreateEnumerator(attribute_);
      auto full_name = ev.name;
      ev.doc_comment = doc_comment_;
      EXPECT(kTokenIdentifier);
      if (is_union) {
        ECHECK(ParseNamespacing(&full_name, &ev.name));
        if (opts.union_value_namespacing) {
          // Since we can't namespace the actual enum identifiers, turn
          // namespace parts into part of the identifier.
          ev.name = full_name;
          std::replace(ev.name.begin(), ev.name.end(), '.', '_');
        }
        if (Is(':')) {
          NEXT();
          ECHECK(ParseType(ev.union_type));
          if (ev.union_type.base_type != BASE_TYPE_STRUCT &&
              ev.union_type.base_type != BASE_TYPE_STRING)
            return Error("union value type may only be table/struct/string");
        } else {
          ev.union_type = Type(BASE_TYPE_STRUCT, LookupCreateStruct(full_name));
        }
        if (!enum_def->uses_multiple_type_instances) {
          auto ins = union_types.insert(std::make_pair(
              ev.union_type.base_type, ev.union_type.struct_def));
          enum_def->uses_multiple_type_instances = (false == ins.second);
        }
      }

      if (Is('=')) {
        NEXT();
        ECHECK(evb.AssignEnumeratorValue(attribute_));
        EXPECT(kTokenIntegerConstant);
      }

      if (opts.proto_mode && Is('[')) {
        NEXT();
        // ignore attributes on enums.
        while (token_ != ']') NEXT();
        NEXT();
      } else {
        // parse attributes in fbs schema
        ECHECK(ParseMetaData(&ev.attributes));
      }

      ECHECK(evb.AcceptEnumerator());
    }
    if (!Is(opts.proto_mode ? ';' : ',')) break;
    NEXT();
  }
  EXPECT('}');

  // At this point, the enum can be empty if input is invalid proto-file.
  if (!enum_def->size())
    return Error("incomplete enum declaration, values not found");

  if (enum_def->attributes.Lookup("bit_flags")) {
    const auto base_width = static_cast<uint64_t>(8 * SizeOf(underlying_type));
    for (auto it = enum_def->Vals().begin(); it != enum_def->Vals().end();
         ++it) {
      auto ev = *it;
      const auto u = ev->GetAsUInt64();
      // Stop manipulations with the sign.
      if (!IsUnsigned(underlying_type) && u == (base_width - 1))
        return Error("underlying type of bit_flags enum must be unsigned");
      if (u >= base_width)
        return Error("bit flag out of range of underlying integral type");
      enum_def->ChangeEnumValue(ev, 1ULL << u);
    }
  }

  enum_def->SortByValue();  // Must be sorted to use MinValue/MaxValue.

  // Ensure enum value uniqueness.
  auto prev_it = enum_def->Vals().begin();
  for (auto it = prev_it + 1; it != enum_def->Vals().end(); ++it) {
    auto prev_ev = *prev_it;
    auto ev = *it;
    if (prev_ev->GetAsUInt64() == ev->GetAsUInt64())
      return Error("all enum values must be unique: " + prev_ev->name +
                   " and " + ev->name + " are both " +
                   NumToString(ev->GetAsInt64()));
  }

  if (dest) *dest = enum_def;
  const auto qualified_name =
      current_namespace_->GetFullyQualifiedName(enum_def->name);
  if (types_.Add(qualified_name, new Type(BASE_TYPE_UNION, nullptr, enum_def)))
    return Error("datatype already exists: " + qualified_name);
  return NoError();
}

CheckedError Parser::StartStruct(const std::string &name, StructDef **dest) {
  auto &struct_def = *LookupCreateStruct(name, true, true);
  if (!struct_def.predecl)
    return Error("datatype already exists: " +
                 current_namespace_->GetFullyQualifiedName(name));
  struct_def.predecl = false;
  struct_def.name = name;
  struct_def.file = file_being_parsed_;
  // Move this struct to the back of the vector just in case it was predeclared,
  // to preserve declaration order.
  *std::remove(structs_.vec.begin(), structs_.vec.end(), &struct_def) =
      &struct_def;
  *dest = &struct_def;
  return NoError();
}

CheckedError Parser::CheckClash(std::vector<FieldDef *> &fields,
                                StructDef *struct_def, const char *suffix,
                                BaseType basetype) {
  auto len = strlen(suffix);
  for (auto it = fields.begin(); it != fields.end(); ++it) {
    auto &fname = (*it)->name;
    if (fname.length() > len &&
        fname.compare(fname.length() - len, len, suffix) == 0 &&
        (*it)->value.type.base_type != BASE_TYPE_UTYPE) {
      auto field =
          struct_def->fields.Lookup(fname.substr(0, fname.length() - len));
      if (field && field->value.type.base_type == basetype)
        return Error("Field " + fname +
                     " would clash with generated functions for field " +
                     field->name);
    }
  }
  return NoError();
}

std::vector<IncludedFile> Parser::GetIncludedFiles() const {
  const auto it = files_included_per_file_.find(file_being_parsed_);
  if (it == files_included_per_file_.end()) { return {}; }

  return { it->second.cbegin(), it->second.cend() };
}

bool Parser::SupportsOptionalScalars(const flatbuffers::IDLOptions &opts) {
  static FLATBUFFERS_CONSTEXPR unsigned long supported_langs =
      IDLOptions::kRust | IDLOptions::kSwift | IDLOptions::kLobster |
      IDLOptions::kKotlin | IDLOptions::kCpp | IDLOptions::kJava |
      IDLOptions::kCSharp | IDLOptions::kTs | IDLOptions::kBinary |
      IDLOptions::kGo | IDLOptions::kPython | IDLOptions::kJson |
      IDLOptions::kNim;
  unsigned long langs = opts.lang_to_generate;
  return (langs > 0 && langs < IDLOptions::kMAX) && !(langs & ~supported_langs);
}
bool Parser::SupportsOptionalScalars() const {
  // Check in general if a language isn't specified.
  return opts.lang_to_generate == 0 || SupportsOptionalScalars(opts);
}

bool Parser::SupportsDefaultVectorsAndStrings() const {
  static FLATBUFFERS_CONSTEXPR unsigned long supported_langs =
      IDLOptions::kRust | IDLOptions::kSwift | IDLOptions::kNim;
  return !(opts.lang_to_generate & ~supported_langs);
}

bool Parser::SupportsAdvancedUnionFeatures() const {
  return (opts.lang_to_generate &
          ~(IDLOptions::kCpp | IDLOptions::kTs | IDLOptions::kPhp |
            IDLOptions::kJava | IDLOptions::kCSharp | IDLOptions::kKotlin |
            IDLOptions::kBinary | IDLOptions::kSwift | IDLOptions::kNim |
            IDLOptions::kJson)) == 0;
}

bool Parser::SupportsAdvancedArrayFeatures() const {
  return (opts.lang_to_generate &
          ~(IDLOptions::kCpp | IDLOptions::kPython | IDLOptions::kJava |
            IDLOptions::kCSharp | IDLOptions::kJsonSchema | IDLOptions::kJson |
            IDLOptions::kBinary | IDLOptions::kRust | IDLOptions::kTs)) == 0;
}

bool Parser::Supports64BitOffsets() const {
  return (opts.lang_to_generate &
          ~(IDLOptions::kCpp | IDLOptions::kJson | IDLOptions::kBinary)) == 0;
}

bool Parser::SupportsUnionUnderlyingType() const {
    return (opts.lang_to_generate & ~(IDLOptions::kCpp | IDLOptions::kTs)) == 0;
}

Namespace *Parser::UniqueNamespace(Namespace *ns) {
  for (auto it = namespaces_.begin(); it != namespaces_.end(); ++it) {
    if (ns->components == (*it)->components) {
      delete ns;
      return *it;
    }
  }
  namespaces_.push_back(ns);
  return ns;
}

std::string Parser::UnqualifiedName(const std::string &full_qualified_name) {
  Namespace *ns = new Namespace();

  std::size_t current, previous = 0;
  current = full_qualified_name.find('.');
  while (current != std::string::npos) {
    ns->components.push_back(
        full_qualified_name.substr(previous, current - previous));
    previous = current + 1;
    current = full_qualified_name.find('.', previous);
  }
  current_namespace_ = UniqueNamespace(ns);
  return full_qualified_name.substr(previous, current - previous);
}

CheckedError Parser::ParseDecl(const char *filename) {
  std::vector<std::string> dc = doc_comment_;
  bool fixed = IsIdent("struct");
  if (!fixed && !IsIdent("table")) return Error("declaration expected");
  NEXT();
  std::string name = attribute_;
  EXPECT(kTokenIdentifier);
  StructDef *struct_def;
  ECHECK(StartStruct(name, &struct_def));
  struct_def->doc_comment = dc;
  struct_def->fixed = fixed;
  if (filename && !opts.project_root.empty()) {
    struct_def->declaration_file =
        &GetPooledString(RelativeToRootPath(opts.project_root, filename));
  }
  ECHECK(ParseMetaData(&struct_def->attributes));
  struct_def->sortbysize =
      struct_def->attributes.Lookup("original_order") == nullptr && !fixed;
  EXPECT('{');
  while (token_ != '}') ECHECK(ParseField(*struct_def));
  if (fixed) {
    const auto force_align = struct_def->attributes.Lookup("force_align");
    if (force_align) {
      size_t align;
      ECHECK(ParseAlignAttribute(force_align->constant, struct_def->minalign,
                                 &align));
      struct_def->minalign = align;
    }
    if (!struct_def->bytesize) return Error("size 0 structs not allowed");
  }
  struct_def->PadLastField(struct_def->minalign);
  // Check if this is a table that has manual id assignments
  auto &fields = struct_def->fields.vec;
  if (!fixed && fields.size()) {
    size_t num_id_fields = 0;
    for (auto it = fields.begin(); it != fields.end(); ++it) {
      if ((*it)->attributes.Lookup("id")) num_id_fields++;
    }
    // If any fields have ids..
    if (num_id_fields || opts.require_explicit_ids) {
      // Then all fields must have them.
      if (num_id_fields != fields.size()) {
        if (opts.require_explicit_ids) {
          return Error(
              "all fields must have an 'id' attribute when "
              "--require-explicit-ids is used");
        } else {
          return Error(
              "either all fields or no fields must have an 'id' attribute");
        }
      }
      // Simply sort by id, then the fields are the same as if no ids had
      // been specified.
      std::sort(fields.begin(), fields.end(), compareFieldDefs);
      // Verify we have a contiguous set, and reassign vtable offsets.
      FLATBUFFERS_ASSERT(fields.size() <=
                         flatbuffers::numeric_limits<voffset_t>::max());
      for (voffset_t i = 0; i < static_cast<voffset_t>(fields.size()); i++) {
        auto &field = *fields[i];
        const auto &id_str = field.attributes.Lookup("id")->constant;

        // Metadata values have a dynamic type, they can be `float`, 'int', or
        // 'string`.
        // The FieldIndexToOffset(i) expects the voffset_t so `id` is limited by
        // this type.
        voffset_t id = 0;
        const auto done = !atot(id_str.c_str(), *this, &id).Check();
        if (!done)
          return Error("field id\'s must be non-negative number, field: " +
                       field.name + ", id: " + id_str);
        if (i != id)
          return Error("field id\'s must be consecutive from 0, id " +
                       NumToString(i) + " missing or set twice, field: " +
                       field.name + ", id: " + id_str);
        field.value.offset = FieldIndexToOffset(i);
      }
    }
  }

  ECHECK(
      CheckClash(fields, struct_def, UnionTypeFieldSuffix(), BASE_TYPE_UNION));
  ECHECK(CheckClash(fields, struct_def, "Type", BASE_TYPE_UNION));
  ECHECK(CheckClash(fields, struct_def, "_length", BASE_TYPE_VECTOR));
  ECHECK(CheckClash(fields, struct_def, "Length", BASE_TYPE_VECTOR));
  ECHECK(CheckClash(fields, struct_def, "_byte_vector", BASE_TYPE_STRING));
  ECHECK(CheckClash(fields, struct_def, "ByteVector", BASE_TYPE_STRING));
  EXPECT('}');
  const auto qualified_name =
      current_namespace_->GetFullyQualifiedName(struct_def->name);
  if (types_.Add(qualified_name,
                 new Type(BASE_TYPE_STRUCT, struct_def, nullptr)))
    return Error("datatype already exists: " + qualified_name);
  return NoError();
}

CheckedError Parser::ParseService(const char *filename) {
  std::vector<std::string> service_comment = doc_comment_;
  NEXT();
  auto service_name = attribute_;
  EXPECT(kTokenIdentifier);
  auto &service_def = *new ServiceDef();
  service_def.name = service_name;
  service_def.file = file_being_parsed_;
  service_def.doc_comment = service_comment;
  service_def.defined_namespace = current_namespace_;
  if (filename != nullptr && !opts.project_root.empty()) {
    service_def.declaration_file =
        &GetPooledString(RelativeToRootPath(opts.project_root, filename));
  }
  if (services_.Add(current_namespace_->GetFullyQualifiedName(service_name),
                    &service_def))
    return Error("service already exists: " + service_name);
  ECHECK(ParseMetaData(&service_def.attributes));
  EXPECT('{');
  do {
    std::vector<std::string> doc_comment = doc_comment_;
    auto rpc_name = attribute_;
    EXPECT(kTokenIdentifier);
    EXPECT('(');
    Type reqtype, resptype;
    ECHECK(ParseTypeIdent(reqtype));
    EXPECT(')');
    EXPECT(':');
    ECHECK(ParseTypeIdent(resptype));
    if (reqtype.base_type != BASE_TYPE_STRUCT || reqtype.struct_def->fixed ||
        resptype.base_type != BASE_TYPE_STRUCT || resptype.struct_def->fixed)
      return Error("rpc request and response types must be tables");
    auto &rpc = *new RPCCall();
    rpc.name = rpc_name;
    rpc.request = reqtype.struct_def;
    rpc.response = resptype.struct_def;
    rpc.doc_comment = doc_comment;
    if (service_def.calls.Add(rpc_name, &rpc))
      return Error("rpc already exists: " + rpc_name);
    ECHECK(ParseMetaData(&rpc.attributes));
    EXPECT(';');
  } while (token_ != '}');
  NEXT();
  return NoError();
}

bool Parser::SetRootType(const char *name) {
  root_struct_def_ = LookupStruct(name);
  if (!root_struct_def_)
    root_struct_def_ =
        LookupStruct(current_namespace_->GetFullyQualifiedName(name));
  return root_struct_def_ != nullptr;
}

void Parser::MarkGenerated() {
  // This function marks all existing definitions as having already
  // been generated, which signals no code for included files should be
  // generated.
  for (auto it = enums_.vec.begin(); it != enums_.vec.end(); ++it) {
    (*it)->generated = true;
  }
  for (auto it = structs_.vec.begin(); it != structs_.vec.end(); ++it) {
    if (!(*it)->predecl) { (*it)->generated = true; }
  }
  for (auto it = services_.vec.begin(); it != services_.vec.end(); ++it) {
    (*it)->generated = true;
  }
}

CheckedError Parser::ParseNamespace() {
  NEXT();
  auto ns = new Namespace();
  namespaces_.push_back(ns);  // Store it here to not leak upon error.
  if (token_ != ';') {
    for (;;) {
      ns->components.push_back(attribute_);
      EXPECT(kTokenIdentifier);
      if (Is('.')) NEXT() else break;
    }
  }
  namespaces_.pop_back();
  current_namespace_ = UniqueNamespace(ns);
  EXPECT(';');
  return NoError();
}

// Best effort parsing of .proto declarations, with the aim to turn them
// in the closest corresponding FlatBuffer equivalent.
// We parse everything as identifiers instead of keywords, since we don't
// want protobuf keywords to become invalid identifiers in FlatBuffers.
CheckedError Parser::ParseProtoDecl() {
  bool isextend = IsIdent("extend");
  if (IsIdent("package")) {
    // These are identical in syntax to FlatBuffer's namespace decl.
    ECHECK(ParseNamespace());
  } else if (IsIdent("message") || isextend) {
    std::vector<std::string> struct_comment = doc_comment_;
    NEXT();
    StructDef *struct_def = nullptr;
    Namespace *parent_namespace = nullptr;
    if (isextend) {
      if (Is('.')) NEXT();  // qualified names may start with a . ?
      auto id = attribute_;
      EXPECT(kTokenIdentifier);
      ECHECK(ParseNamespacing(&id, nullptr));
      struct_def = LookupCreateStruct(id, false);
      if (!struct_def)
        return Error("cannot extend unknown message type: " + id);
    } else {
      std::string name = attribute_;
      EXPECT(kTokenIdentifier);
      ECHECK(StartStruct(name, &struct_def));
      // Since message definitions can be nested, we create a new namespace.
      auto ns = new Namespace();
      // Copy of current namespace.
      *ns = *current_namespace_;
      // But with current message name.
      ns->components.push_back(name);
      ns->from_table++;
      parent_namespace = current_namespace_;
      current_namespace_ = UniqueNamespace(ns);
    }
    struct_def->doc_comment = struct_comment;
    ECHECK(ParseProtoFields(struct_def, isextend, false));
    if (!isextend) { current_namespace_ = parent_namespace; }
    if (Is(';')) NEXT();
  } else if (IsIdent("enum")) {
    // These are almost the same, just with different terminator:
    EnumDef *enum_def;
    ECHECK(ParseEnum(false, &enum_def, nullptr));
    if (Is(';')) NEXT();
    // Temp: remove any duplicates, as .fbs files can't handle them.
    enum_def->RemoveDuplicates();
  } else if (IsIdent("syntax")) {  // Skip these.
    NEXT();
    EXPECT('=');
    EXPECT(kTokenStringConstant);
    EXPECT(';');
  } else if (IsIdent("option")) {  // Skip these.
    ECHECK(ParseProtoOption());
    EXPECT(';');
  } else if (IsIdent("service")) {  // Skip these.
    NEXT();
    EXPECT(kTokenIdentifier);
    ECHECK(ParseProtoCurliesOrIdent());
  } else {
    return Error("don\'t know how to parse .proto declaration starting with " +
                 TokenToStringId(token_));
  }
  return NoError();
}

CheckedError Parser::StartEnum(const std::string &name, bool is_union,
                               EnumDef **dest) {
  auto &enum_def = *new EnumDef();
  enum_def.name = name;
  enum_def.file = file_being_parsed_;
  enum_def.doc_comment = doc_comment_;
  enum_def.is_union = is_union;
  enum_def.defined_namespace = current_namespace_;
  const auto qualified_name = current_namespace_->GetFullyQualifiedName(name);
  if (enums_.Add(qualified_name, &enum_def))
    return Error("enum already exists: " + qualified_name);
  enum_def.underlying_type.base_type =
      is_union ? BASE_TYPE_UTYPE : BASE_TYPE_INT;
  enum_def.underlying_type.enum_def = &enum_def;
  if (dest) *dest = &enum_def;
  return NoError();
}

CheckedError Parser::ParseProtoFields(StructDef *struct_def, bool isextend,
                                      bool inside_oneof) {
  EXPECT('{');
  while (token_ != '}') {
    if (IsIdent("message") || IsIdent("extend") || IsIdent("enum")) {
      // Nested declarations.
      ECHECK(ParseProtoDecl());
    } else if (IsIdent("extensions")) {  // Skip these.
      NEXT();
      EXPECT(kTokenIntegerConstant);
      if (Is(kTokenIdentifier)) {
        NEXT();  // to
        NEXT();  // num
      }
      EXPECT(';');
    } else if (IsIdent("option")) {  // Skip these.
      ECHECK(ParseProtoOption());
      EXPECT(';');
    } else if (IsIdent("reserved")) {  // Skip these.
      /**
       * Reserved proto ids can be comma seperated (e.g. 1,2,4,5;)
       * or range based (e.g. 9 to 11;)
       * or combination of them (e.g. 1,2,9 to 11,4,5;)
       * It will be ended by a semicolon.
       */
      NEXT();
      bool range = false;
      voffset_t from = 0;

      while (!Is(';')) {
        if (token_ == kTokenIntegerConstant) {
          voffset_t attribute = 0;
          bool done = StringToNumber(attribute_.c_str(), &attribute);
          if (!done)
            return Error("Protobuf has non positive number in reserved ids");

          if (range) {
            for (voffset_t id = from + 1; id <= attribute; id++)
              struct_def->reserved_ids.push_back(id);

            range = false;
          } else {
            struct_def->reserved_ids.push_back(attribute);
          }

          from = attribute;
        }

        if (attribute_ == "to") range = true;

        NEXT();
      }  // A variety of formats, just skip.

      NEXT();
    } else if (IsIdent("map")) {
      ECHECK(ParseProtoMapField(struct_def));
    } else {
      std::vector<std::string> field_comment = doc_comment_;
      // Parse the qualifier.
      bool required = false;
      bool repeated = false;
      bool oneof = false;
      if (!inside_oneof) {
        if (IsIdent("optional")) {
          // This is the default.
          NEXT();
        } else if (IsIdent("required")) {
          required = true;
          NEXT();
        } else if (IsIdent("repeated")) {
          repeated = true;
          NEXT();
        } else if (IsIdent("oneof")) {
          oneof = true;
          NEXT();
        } else {
          // can't error, proto3 allows decls without any of the above.
        }
      }
      StructDef *anonymous_struct = nullptr;
      EnumDef *oneof_union = nullptr;
      Type type;
      if (IsIdent("group") || oneof) {
        if (!oneof) NEXT();
        if (oneof && opts.proto_oneof_union) {
          auto name = ConvertCase(attribute_, Case::kUpperCamel) + "Union";
          ECHECK(StartEnum(name, true, &oneof_union));
          type = Type(BASE_TYPE_UNION, nullptr, oneof_union);
        } else {
          auto name = "Anonymous" + NumToString(anonymous_counter_++);
          ECHECK(StartStruct(name, &anonymous_struct));
          type = Type(BASE_TYPE_STRUCT, anonymous_struct);
        }
      } else {
        ECHECK(ParseTypeFromProtoType(&type));
      }
      // Repeated elements get mapped to a vector.
      if (repeated) {
        type.element = type.base_type;
        type.base_type = BASE_TYPE_VECTOR;
        if (type.element == BASE_TYPE_VECTOR) {
          // We have a vector or vectors, which FlatBuffers doesn't support.
          // For now make it a vector of string (since the source is likely
          // "repeated bytes").
          // TODO(wvo): A better solution would be to wrap this in a table.
          type.element = BASE_TYPE_STRING;
        }
      }
      std::string name = attribute_;
      EXPECT(kTokenIdentifier);
      std::string proto_field_id;
      if (!oneof) {
        // Parse the field id. Since we're just translating schemas, not
        // any kind of binary compatibility, we can safely ignore these, and
        // assign our own.
        EXPECT('=');
        proto_field_id = attribute_;
        EXPECT(kTokenIntegerConstant);
      }
      FieldDef *field = nullptr;
      if (isextend) {
        // We allow a field to be re-defined when extending.
        // TODO: are there situations where that is problematic?
        field = struct_def->fields.Lookup(name);
      }
      if (!field) ECHECK(AddField(*struct_def, name, type, &field));
      field->doc_comment = field_comment;
      if (!proto_field_id.empty() || oneof) {
        auto val = new Value();
        val->constant = proto_field_id;
        field->attributes.Add("id", val);
      }
      if (!IsScalar(type.base_type) && required) {
        field->presence = FieldDef::kRequired;
      }
      // See if there's a default specified.
      if (Is('[')) {
        NEXT();
        for (;;) {
          auto key = attribute_;
          ECHECK(ParseProtoKey());
          EXPECT('=');
          auto val = attribute_;
          ECHECK(ParseProtoCurliesOrIdent());
          if (key == "default") {
            // Temp: skip non-numeric and non-boolean defaults (enums).
            auto numeric = strpbrk(val.c_str(), "0123456789-+.");
            if (IsFloat(type.base_type) &&
                (val == "inf" || val == "+inf" || val == "-inf")) {
              // Prefer to be explicit with +inf.
              field->value.constant = val == "inf" ? "+inf" : val;
            } else if (IsScalar(type.base_type) && numeric == val.c_str()) {
              field->value.constant = val;
            } else if (val == "true") {
              field->value.constant = val;
            }  // "false" is default, no need to handle explicitly.
          } else if (key == "deprecated") {
            field->deprecated = val == "true";
          }
          if (!Is(',')) break;
          NEXT();
        }
        EXPECT(']');
      }
      if (anonymous_struct) {
        ECHECK(ParseProtoFields(anonymous_struct, false, oneof));
        if (Is(';')) NEXT();
      } else if (oneof_union) {
        // Parse into a temporary StructDef, then transfer fields into an
        // EnumDef describing the oneof as a union.
        StructDef oneof_struct;
        ECHECK(ParseProtoFields(&oneof_struct, false, oneof));
        if (Is(';')) NEXT();
        for (auto field_it = oneof_struct.fields.vec.begin();
             field_it != oneof_struct.fields.vec.end(); ++field_it) {
          const auto &oneof_field = **field_it;
          const auto &oneof_type = oneof_field.value.type;
          if (oneof_type.base_type != BASE_TYPE_STRUCT ||
              !oneof_type.struct_def || oneof_type.struct_def->fixed)
            return Error("oneof '" + name +
                         "' cannot be mapped to a union because member '" +
                         oneof_field.name + "' is not a table type.");
          EnumValBuilder evb(*this, *oneof_union);
          auto ev = evb.CreateEnumerator(oneof_type.struct_def->name);
          ev->union_type = oneof_type;
          ev->doc_comment = oneof_field.doc_comment;
          ECHECK(evb.AcceptEnumerator(oneof_field.name));
        }
      } else {
        EXPECT(';');
      }
    }
  }
  NEXT();
  return NoError();
}

CheckedError Parser::ParseProtoMapField(StructDef *struct_def) {
  NEXT();
  EXPECT('<');
  Type key_type;
  ECHECK(ParseType(key_type));
  EXPECT(',');
  Type value_type;
  ECHECK(ParseType(value_type));
  EXPECT('>');
  auto field_name = attribute_;
  NEXT();
  EXPECT('=');
  std::string proto_field_id = attribute_;
  EXPECT(kTokenIntegerConstant);
  EXPECT(';');

  auto entry_table_name = ConvertCase(field_name, Case::kUpperCamel) + "Entry";
  StructDef *entry_table;
  ECHECK(StartStruct(entry_table_name, &entry_table));
  entry_table->has_key = true;
  FieldDef *key_field;
  ECHECK(AddField(*entry_table, "key", key_type, &key_field));
  key_field->key = true;
  FieldDef *value_field;
  ECHECK(AddField(*entry_table, "value", value_type, &value_field));

  Type field_type;
  field_type.base_type = BASE_TYPE_VECTOR;
  field_type.element = BASE_TYPE_STRUCT;
  field_type.struct_def = entry_table;
  FieldDef *field;
  ECHECK(AddField(*struct_def, field_name, field_type, &field));
  if (!proto_field_id.empty()) {
    auto val = new Value();
    val->constant = proto_field_id;
    field->attributes.Add("id", val);
  }

  return NoError();
}

CheckedError Parser::ParseProtoKey() {
  if (token_ == '(') {
    NEXT();
    // Skip "(a.b)" style custom attributes.
    while (token_ == '.' || token_ == kTokenIdentifier) NEXT();
    EXPECT(')');
    while (Is('.')) {
      NEXT();
      EXPECT(kTokenIdentifier);
    }
  } else {
    EXPECT(kTokenIdentifier);
  }
  return NoError();
}

CheckedError Parser::ParseProtoCurliesOrIdent() {
  if (Is('{')) {
    NEXT();
    for (int nesting = 1; nesting;) {
      if (token_ == '{')
        nesting++;
      else if (token_ == '}')
        nesting--;
      NEXT();
    }
  } else {
    NEXT();  // Any single token.
  }
  return NoError();
}

CheckedError Parser::ParseProtoOption() {
  NEXT();
  ECHECK(ParseProtoKey());
  EXPECT('=');
  ECHECK(ParseProtoCurliesOrIdent());
  return NoError();
}

// Parse a protobuf type, and map it to the corresponding FlatBuffer one.
CheckedError Parser::ParseTypeFromProtoType(Type *type) {
  struct type_lookup {
    const char *proto_type;
    BaseType fb_type, element;
  };
  static type_lookup lookup[] = {
    { "float", BASE_TYPE_FLOAT, BASE_TYPE_NONE },
    { "double", BASE_TYPE_DOUBLE, BASE_TYPE_NONE },
    { "int32", BASE_TYPE_INT, BASE_TYPE_NONE },
    { "int64", BASE_TYPE_LONG, BASE_TYPE_NONE },
    { "uint32", BASE_TYPE_UINT, BASE_TYPE_NONE },
    { "uint64", BASE_TYPE_ULONG, BASE_TYPE_NONE },
    { "sint32", BASE_TYPE_INT, BASE_TYPE_NONE },
    { "sint64", BASE_TYPE_LONG, BASE_TYPE_NONE },
    { "fixed32", BASE_TYPE_UINT, BASE_TYPE_NONE },
    { "fixed64", BASE_TYPE_ULONG, BASE_TYPE_NONE },
    { "sfixed32", BASE_TYPE_INT, BASE_TYPE_NONE },
    { "sfixed64", BASE_TYPE_LONG, BASE_TYPE_NONE },
    { "bool", BASE_TYPE_BOOL, BASE_TYPE_NONE },
    { "string", BASE_TYPE_STRING, BASE_TYPE_NONE },
    { "bytes", BASE_TYPE_VECTOR, BASE_TYPE_UCHAR },
    { nullptr, BASE_TYPE_NONE, BASE_TYPE_NONE }
  };
  for (auto tl = lookup; tl->proto_type; tl++) {
    if (attribute_ == tl->proto_type) {
      type->base_type = tl->fb_type;
      type->element = tl->element;
      NEXT();
      return NoError();
    }
  }
  if (Is('.')) NEXT();  // qualified names may start with a . ?
  ECHECK(ParseTypeIdent(*type));
  return NoError();
}

CheckedError Parser::SkipAnyJsonValue() {
  ParseDepthGuard depth_guard(this);
  ECHECK(depth_guard.Check());

  switch (token_) {
    case '{': {
      size_t fieldn_outer = 0;
      return ParseTableDelimiters(fieldn_outer, nullptr,
                                  [&](const std::string &, size_t &fieldn,
                                      const StructDef *) -> CheckedError {
                                    ECHECK(SkipAnyJsonValue());
                                    fieldn++;
                                    return NoError();
                                  });
    }
    case '[': {
      size_t count = 0;
      return ParseVectorDelimiters(
          count, [&](size_t &) -> CheckedError { return SkipAnyJsonValue(); });
    }
    case kTokenStringConstant:
    case kTokenIntegerConstant:
    case kTokenFloatConstant: NEXT(); break;
    default:
      if (IsIdent("true") || IsIdent("false") || IsIdent("null") ||
          IsIdent("inf")) {
        NEXT();
      } else
        return TokenError();
  }
  return NoError();
}

CheckedError Parser::ParseFlexBufferNumericConstant(
    flexbuffers::Builder *builder) {
  double d;
  if (!StringToNumber(attribute_.c_str(), &d))
    return Error("unexpected floating-point constant: " + attribute_);
  builder->Double(d);
  return NoError();
}

CheckedError Parser::ParseFlexBufferValue(flexbuffers::Builder *builder) {
  ParseDepthGuard depth_guard(this);
  ECHECK(depth_guard.Check());

  switch (token_) {
    case '{': {
      auto start = builder->StartMap();
      size_t fieldn_outer = 0;
      auto err =
          ParseTableDelimiters(fieldn_outer, nullptr,
                               [&](const std::string &name, size_t &fieldn,
                                   const StructDef *) -> CheckedError {
                                 builder->Key(name);
                                 ECHECK(ParseFlexBufferValue(builder));
                                 fieldn++;
                                 return NoError();
                               });
      ECHECK(err);
      builder->EndMap(start);
      if (builder->HasDuplicateKeys())
        return Error("FlexBuffers map has duplicate keys");
      break;
    }
    case '[': {
      auto start = builder->StartVector();
      size_t count = 0;
      ECHECK(ParseVectorDelimiters(count, [&](size_t &) -> CheckedError {
        return ParseFlexBufferValue(builder);
      }));
      builder->EndVector(start, false, false);
      break;
    }
    case kTokenStringConstant:
      builder->String(attribute_);
      EXPECT(kTokenStringConstant);
      break;
    case kTokenIntegerConstant:
      builder->Int(StringToInt(attribute_.c_str()));
      EXPECT(kTokenIntegerConstant);
      break;
    case kTokenFloatConstant: {
      double d;
      StringToNumber(attribute_.c_str(), &d);
      builder->Double(d);
      EXPECT(kTokenFloatConstant);
      break;
    }
    case '-':
    case '+': {
      // `[-+]?(nan|inf|infinity)`, see ParseSingleValue().
      const auto sign = static_cast<char>(token_);
      NEXT();
      if (token_ != kTokenIdentifier)
        return Error("floating-point constant expected");
      attribute_.insert(size_t(0), size_t(1), sign);
      ECHECK(ParseFlexBufferNumericConstant(builder));
      NEXT();
      break;
    }
    default:
      if (IsIdent("true")) {
        builder->Bool(true);
        NEXT();
      } else if (IsIdent("false")) {
        builder->Bool(false);
        NEXT();
      } else if (IsIdent("null")) {
        builder->Null();
        NEXT();
      } else if (IsIdent("inf") || IsIdent("infinity") || IsIdent("nan")) {
        ECHECK(ParseFlexBufferNumericConstant(builder));
        NEXT();
      } else
        return TokenError();
  }
  return NoError();
}

bool Parser::ParseFlexBuffer(const char *source, const char *source_filename,
                             flexbuffers::Builder *builder) {
  const auto initial_depth = parse_depth_counter_;
  (void)initial_depth;
  auto ok = !StartParseFile(source, source_filename).Check() &&
            !ParseFlexBufferValue(builder).Check();
  if (ok) builder->Finish();
  FLATBUFFERS_ASSERT(initial_depth == parse_depth_counter_);
  return ok;
}

bool Parser::Parse(const char *source, const char **include_paths,
                   const char *source_filename) {
  const auto initial_depth = parse_depth_counter_;
  (void)initial_depth;
  bool r;

  if (opts.use_flexbuffers) {
    r = ParseFlexBuffer(source, source_filename, &flex_builder_);
  } else {
    r = !ParseRoot(source, include_paths, source_filename).Check();
  }
  FLATBUFFERS_ASSERT(initial_depth == parse_depth_counter_);
  return r;
}

bool Parser::ParseJson(const char *json, const char *json_filename) {
  const auto initial_depth = parse_depth_counter_;
  (void)initial_depth;
  builder_.Clear();
  const auto done =
      !StartParseFile(json, json_filename).Check() && !DoParseJson().Check();
  FLATBUFFERS_ASSERT(initial_depth == parse_depth_counter_);
  return done;
}

std::ptrdiff_t Parser::BytesConsumed() const {
  return std::distance(source_, prev_cursor_);
}

CheckedError Parser::StartParseFile(const char *source,
                                    const char *source_filename) {
  file_being_parsed_ = source_filename ? source_filename : "";
  source_ = source;
  ResetState(source_);
  error_.clear();
  ECHECK(SkipByteOrderMark());
  NEXT();
  if (Is(kTokenEof)) return Error("input file is empty");
  return NoError();
}

CheckedError Parser::ParseRoot(const char *source, const char **include_paths,
                               const char *source_filename) {
  ECHECK(DoParse(source, include_paths, source_filename, nullptr));

  // Check that all types were defined.
  for (auto it = structs_.vec.begin(); it != structs_.vec.end();) {
    auto &struct_def = **it;
    if (struct_def.predecl) {
      if (opts.proto_mode) {
        // Protos allow enums to be used before declaration, so check if that
        // is the case here.
        EnumDef *enum_def = nullptr;
        for (size_t components =
                 struct_def.defined_namespace->components.size() + 1;
             components && !enum_def; components--) {
          auto qualified_name =
              struct_def.defined_namespace->GetFullyQualifiedName(
                  struct_def.name, components - 1);
          enum_def = LookupEnum(qualified_name);
        }
        if (enum_def) {
          // This is pretty slow, but a simple solution for now.
          auto initial_count = struct_def.refcount;
          for (auto struct_it = structs_.vec.begin();
               struct_it != structs_.vec.end(); ++struct_it) {
            auto &sd = **struct_it;
            for (auto field_it = sd.fields.vec.begin();
                 field_it != sd.fields.vec.end(); ++field_it) {
              auto &field = **field_it;
              if (field.value.type.struct_def == &struct_def) {
                field.value.type.struct_def = nullptr;
                field.value.type.enum_def = enum_def;
                auto &bt = IsVector(field.value.type)
                               ? field.value.type.element
                               : field.value.type.base_type;
                FLATBUFFERS_ASSERT(bt == BASE_TYPE_STRUCT);
                bt = enum_def->underlying_type.base_type;
                struct_def.refcount--;
                enum_def->refcount++;
              }
            }
          }
          if (struct_def.refcount)
            return Error("internal: " + NumToString(struct_def.refcount) + "/" +
                         NumToString(initial_count) +
                         " use(s) of pre-declaration enum not accounted for: " +
                         enum_def->name);
          structs_.dict.erase(structs_.dict.find(struct_def.name));
          it = structs_.vec.erase(it);
          delete &struct_def;
          continue;  // Skip error.
        }
      }
      auto err = "type referenced but not defined (check namespace): " +
                 struct_def.name;
      if (struct_def.original_location)
        err += ", originally at: " + *struct_def.original_location;
      return Error(err);
    }
    ++it;
  }

  // This check has to happen here and not earlier, because only now do we
  // know for sure what the type of these are.
  for (auto it = enums_.vec.begin(); it != enums_.vec.end(); ++it) {
    auto &enum_def = **it;
    if (enum_def.is_union) {
      for (auto val_it = enum_def.Vals().begin();
           val_it != enum_def.Vals().end(); ++val_it) {
        auto &val = **val_it;

        if (!(opts.lang_to_generate != 0 && SupportsAdvancedUnionFeatures()) &&
            (IsStruct(val.union_type) || IsString(val.union_type)))

          return Error(
              "only tables can be union elements in the generated language: " +
              val.name);
      }
    }
  }

  auto err = CheckPrivateLeak();
  if (err.Check()) return err;

  // Parse JSON object only if the scheme has been parsed.
  if (token_ == '{') { ECHECK(DoParseJson()); }
  return NoError();
}

CheckedError Parser::CheckPrivateLeak() {
  if (!opts.no_leak_private_annotations) return NoError();
  // Iterate over all structs/tables to validate we arent leaking
  // any private (structs/tables/enums)
  for (auto it = structs_.vec.begin(); it != structs_.vec.end(); it++) {
    auto &struct_def = **it;
    for (auto fld_it = struct_def.fields.vec.begin();
         fld_it != struct_def.fields.vec.end(); ++fld_it) {
      auto &field = **fld_it;

      if (field.value.type.enum_def) {
        auto err =
            CheckPrivatelyLeakedFields(struct_def, *field.value.type.enum_def);
        if (err.Check()) { return err; }
      } else if (field.value.type.struct_def) {
        auto err = CheckPrivatelyLeakedFields(struct_def,
                                              *field.value.type.struct_def);
        if (err.Check()) { return err; }
      }
    }
  }
  // Iterate over all enums to validate we arent leaking
  // any private (structs/tables)
  for (auto it = enums_.vec.begin(); it != enums_.vec.end(); ++it) {
    auto &enum_def = **it;
    if (enum_def.is_union) {
      for (auto val_it = enum_def.Vals().begin();
           val_it != enum_def.Vals().end(); ++val_it) {
        auto &val = **val_it;
        if (val.union_type.struct_def) {
          auto err =
              CheckPrivatelyLeakedFields(enum_def, *val.union_type.struct_def);
          if (err.Check()) { return err; }
        }
      }
    }
  }
  return NoError();
}

CheckedError Parser::CheckPrivatelyLeakedFields(const Definition &def,
                                                const Definition &value_type) {
  if (!opts.no_leak_private_annotations) return NoError();
  const auto is_private = def.attributes.Lookup("private");
  const auto is_field_private = value_type.attributes.Lookup("private");
  if (!is_private && is_field_private) {
    return Error(
        "Leaking private implementation, verify all objects have similar "
        "annotations");
  }
  return NoError();
}

CheckedError Parser::DoParse(const char *source, const char **include_paths,
                             const char *source_filename,
                             const char *include_filename) {
  uint64_t source_hash = 0;
  if (source_filename) {
    // If the file is in-memory, don't include its contents in the hash as we
    // won't be able to load them later.
    if (FileExists(source_filename))
      source_hash = HashFile(source_filename, source);
    else
      source_hash = HashFile(source_filename, nullptr);

    if (included_files_.find(source_hash) == included_files_.end()) {
      included_files_[source_hash] = include_filename ? include_filename : "";
      files_included_per_file_[source_filename] = std::set<IncludedFile>();
    } else {
      return NoError();
    }
  }
  if (!include_paths) {
    static const char *current_directory[] = { "", nullptr };
    include_paths = current_directory;
  }
  field_stack_.clear();
  builder_.Clear();
  // Start with a blank namespace just in case this file doesn't have one.
  current_namespace_ = empty_namespace_;

  ECHECK(StartParseFile(source, source_filename));

  // Includes must come before type declarations:
  for (;;) {
    // Parse pre-include proto statements if any:
    if (opts.proto_mode && (attribute_ == "option" || attribute_ == "syntax" ||
                            attribute_ == "package")) {
      ECHECK(ParseProtoDecl());
    } else if (IsIdent("native_include")) {
      NEXT();
      native_included_files_.emplace_back(attribute_);
      EXPECT(kTokenStringConstant);
      EXPECT(';');
    } else if (IsIdent("include") || (opts.proto_mode && IsIdent("import"))) {
      NEXT();
      if (opts.proto_mode && attribute_ == "public") NEXT();
      auto name = flatbuffers::PosixPath(attribute_.c_str());
      EXPECT(kTokenStringConstant);
      // Look for the file relative to the directory of the current file.
      std::string filepath;
      if (source_filename) {
        auto source_file_directory =
            flatbuffers::StripFileName(source_filename);
        filepath = flatbuffers::ConCatPathFileName(source_file_directory, name);
      }
      if (filepath.empty() || !FileExists(filepath.c_str())) {
        // Look for the file in include_paths.
        for (auto paths = include_paths; paths && *paths; paths++) {
          filepath = flatbuffers::ConCatPathFileName(*paths, name);
          if (FileExists(filepath.c_str())) break;
        }
      }
      if (filepath.empty())
        return Error("unable to locate include file: " + name);
      if (source_filename) {
        IncludedFile included_file;
        included_file.filename = filepath;
        included_file.schema_name = name;
        files_included_per_file_[source_filename].insert(included_file);
      }

      std::string contents;
      bool file_loaded = LoadFile(filepath.c_str(), true, &contents);
      if (included_files_.find(HashFile(filepath.c_str(), contents.c_str())) ==
          included_files_.end()) {
        // We found an include file that we have not parsed yet.
        // Parse it.
        if (!file_loaded) return Error("unable to load include file: " + name);
        ECHECK(DoParse(contents.c_str(), include_paths, filepath.c_str(),
                       name.c_str()));
        // We generally do not want to output code for any included files:
        if (!opts.generate_all) MarkGenerated();
        // Reset these just in case the included file had them, and the
        // parent doesn't.
        root_struct_def_ = nullptr;
        file_identifier_.clear();
        file_extension_.clear();
        // This is the easiest way to continue this file after an include:
        // instead of saving and restoring all the state, we simply start the
        // file anew. This will cause it to encounter the same include
        // statement again, but this time it will skip it, because it was
        // entered into included_files_.
        // This is recursive, but only go as deep as the number of include
        // statements.
        included_files_.erase(source_hash);
        return DoParse(source, include_paths, source_filename,
                       include_filename);
      }
      EXPECT(';');
    } else {
      break;
    }
  }
  // Now parse all other kinds of declarations:
  while (token_ != kTokenEof) {
    if (opts.proto_mode) {
      ECHECK(ParseProtoDecl());
    } else if (IsIdent("namespace")) {
      ECHECK(ParseNamespace());
    } else if (token_ == '{') {
      return NoError();
    } else if (IsIdent("enum")) {
      ECHECK(ParseEnum(false, nullptr, source_filename));
    } else if (IsIdent("union")) {
      ECHECK(ParseEnum(true, nullptr, source_filename));
    } else if (IsIdent("root_type")) {
      NEXT();
      auto root_type = attribute_;
      EXPECT(kTokenIdentifier);
      ECHECK(ParseNamespacing(&root_type, nullptr));
      if (opts.root_type.empty()) {
        if (!SetRootType(root_type.c_str()))
          return Error("unknown root type: " + root_type);
        if (root_struct_def_->fixed) return Error("root type must be a table");
      }
      EXPECT(';');
    } else if (IsIdent("file_identifier")) {
      NEXT();
      file_identifier_ = attribute_;
      EXPECT(kTokenStringConstant);
      if (file_identifier_.length() != flatbuffers::kFileIdentifierLength)
        return Error("file_identifier must be exactly " +
                     NumToString(flatbuffers::kFileIdentifierLength) +
                     " characters");
      EXPECT(';');
    } else if (IsIdent("file_extension")) {
      NEXT();
      file_extension_ = attribute_;
      EXPECT(kTokenStringConstant);
      EXPECT(';');
    } else if (IsIdent("include")) {
      return Error("includes must come before declarations");
    } else if (IsIdent("attribute")) {
      NEXT();
      auto name = attribute_;
      if (Is(kTokenIdentifier)) {
        NEXT();
      } else {
        EXPECT(kTokenStringConstant);
      }
      EXPECT(';');
      known_attributes_[name] = false;
    } else if (IsIdent("rpc_service")) {
      ECHECK(ParseService(source_filename));
    } else {
      ECHECK(ParseDecl(source_filename));
    }
  }
  EXPECT(kTokenEof);
  if (opts.warnings_as_errors && has_warning_) {
    return Error("treating warnings as errors, failed due to above warnings");
  }
  return NoError();
}

CheckedError Parser::DoParseJson() {
  if (token_ != '{') {
    EXPECT('{');
  } else {
    if (!root_struct_def_) return Error("no root type set to parse json with");
    if (builder_.GetSize()) {
      return Error("cannot have more than one json object in a file");
    }
    uoffset_t toff;
    ECHECK(ParseTable(*root_struct_def_, nullptr, &toff));
    if (opts.size_prefixed) {
      builder_.FinishSizePrefixed(
          Offset<Table>(toff),
          file_identifier_.length() ? file_identifier_.c_str() : nullptr);
    } else {
      builder_.Finish(Offset<Table>(toff), file_identifier_.length()
                                               ? file_identifier_.c_str()
                                               : nullptr);
    }
  }
  if (opts.require_json_eof) {
    // Check that JSON file doesn't contain more objects or IDL directives.
    // Comments after JSON are allowed.
    EXPECT(kTokenEof);
  }
  return NoError();
}

std::set<std::string> Parser::GetIncludedFilesRecursive(
    const std::string &file_name) const {
  std::set<std::string> included_files;
  std::list<std::string> to_process;

  if (file_name.empty()) return included_files;
  to_process.push_back(file_name);

  while (!to_process.empty()) {
    std::string current = to_process.front();
    to_process.pop_front();
    included_files.insert(current);

    // Workaround the lack of const accessor in C++98 maps.
    auto &new_files =
        (*const_cast<std::map<std::string, std::set<IncludedFile>> *>(
            &files_included_per_file_))[current];
    for (auto it = new_files.begin(); it != new_files.end(); ++it) {
      if (included_files.find(it->filename) == included_files.end())
        to_process.push_back(it->filename);
    }
  }

  return included_files;
}

// Schema serialization functionality:

static flatbuffers::Offset<
    flatbuffers::Vector<flatbuffers::Offset<reflection::KeyValue>>>
SerializeAttributesCommon(const SymbolTable<Value> &attributes,
                          FlatBufferBuilder *builder, const Parser &parser) {
  std::vector<flatbuffers::Offset<reflection::KeyValue>> attrs;
  for (auto kv = attributes.dict.begin(); kv != attributes.dict.end(); ++kv) {
    auto it = parser.known_attributes_.find(kv->first);
    FLATBUFFERS_ASSERT(it != parser.known_attributes_.end());
    if (parser.opts.binary_schema_builtins || !it->second) {
      auto key = builder->CreateString(kv->first);
      auto val = builder->CreateString(kv->second->constant);
      attrs.push_back(reflection::CreateKeyValue(*builder, key, val));
    }
  }
  if (attrs.size()) {
    return builder->CreateVectorOfSortedTables(&attrs);
  } else {
    return 0;
  }
}

static bool DeserializeAttributesCommon(
    SymbolTable<Value> &attributes, Parser &parser,
    const Vector<Offset<reflection::KeyValue>> *attrs) {
  if (attrs == nullptr) return true;
  for (uoffset_t i = 0; i < attrs->size(); ++i) {
    auto kv = attrs->Get(i);
    auto value = new Value();
    if (kv->value()) { value->constant = kv->value()->str(); }
    if (attributes.Add(kv->key()->str(), value)) {
      delete value;
      return false;
    }
    parser.known_attributes_[kv->key()->str()];
  }
  return true;
}

void Parser::Serialize() {
  builder_.Clear();
  AssignIndices(structs_.vec);
  AssignIndices(enums_.vec);
  std::vector<Offset<reflection::Object>> object_offsets;
  std::set<std::string> files;
  for (auto it = structs_.vec.begin(); it != structs_.vec.end(); ++it) {
    auto offset = (*it)->Serialize(&builder_, *this);
    object_offsets.push_back(offset);
    (*it)->serialized_location = offset.o;
    const std::string *file = (*it)->declaration_file;
    if (file) files.insert(*file);
  }
  std::vector<Offset<reflection::Enum>> enum_offsets;
  for (auto it = enums_.vec.begin(); it != enums_.vec.end(); ++it) {
    auto offset = (*it)->Serialize(&builder_, *this);
    enum_offsets.push_back(offset);
    const std::string *file = (*it)->declaration_file;
    if (file) files.insert(*file);
  }
  std::vector<Offset<reflection::Service>> service_offsets;
  for (auto it = services_.vec.begin(); it != services_.vec.end(); ++it) {
    auto offset = (*it)->Serialize(&builder_, *this);
    service_offsets.push_back(offset);
    const std::string *file = (*it)->declaration_file;
    if (file) files.insert(*file);
  }

  // Create Schemafiles vector of tables.
  flatbuffers::Offset<
      flatbuffers::Vector<flatbuffers::Offset<reflection::SchemaFile>>>
      schema_files__;
  if (!opts.project_root.empty()) {
    std::vector<Offset<reflection::SchemaFile>> schema_files;
    std::vector<Offset<flatbuffers::String>> included_files;
    for (auto f = files_included_per_file_.begin();
         f != files_included_per_file_.end(); f++) {
      const auto filename__ = builder_.CreateSharedString(
          RelativeToRootPath(opts.project_root, f->first));
      for (auto i = f->second.begin(); i != f->second.end(); i++) {
        included_files.push_back(builder_.CreateSharedString(
            RelativeToRootPath(opts.project_root, i->filename)));
      }
      const auto included_files__ = builder_.CreateVector(included_files);
      included_files.clear();

      schema_files.push_back(
          reflection::CreateSchemaFile(builder_, filename__, included_files__));
    }
    schema_files__ = builder_.CreateVectorOfSortedTables(&schema_files);
  }

  const auto objs__ = builder_.CreateVectorOfSortedTables(&object_offsets);
  const auto enum__ = builder_.CreateVectorOfSortedTables(&enum_offsets);
  const auto fiid__ = builder_.CreateString(file_identifier_);
  const auto fext__ = builder_.CreateString(file_extension_);
  const auto serv__ = builder_.CreateVectorOfSortedTables(&service_offsets);
  const auto schema_offset = reflection::CreateSchema(
      builder_, objs__, enum__, fiid__, fext__,
      (root_struct_def_ ? root_struct_def_->serialized_location : 0), serv__,
      static_cast<reflection::AdvancedFeatures>(advanced_features_),
      schema_files__);
  if (opts.size_prefixed) {
    builder_.FinishSizePrefixed(schema_offset, reflection::SchemaIdentifier());
  } else {
    builder_.Finish(schema_offset, reflection::SchemaIdentifier());
  }
}

Offset<reflection::Object> StructDef::Serialize(FlatBufferBuilder *builder,
                                                const Parser &parser) const {
  std::vector<Offset<reflection::Field>> field_offsets;
  for (auto it = fields.vec.begin(); it != fields.vec.end(); ++it) {
    field_offsets.push_back((*it)->Serialize(
        builder, static_cast<uint16_t>(it - fields.vec.begin()), parser));
  }
  const auto qualified_name = defined_namespace->GetFullyQualifiedName(name);
  const auto name__ = builder->CreateString(qualified_name);
  const auto flds__ = builder->CreateVectorOfSortedTables(&field_offsets);
  const auto attr__ = SerializeAttributes(builder, parser);
  const auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                          ? builder->CreateVectorOfStrings(doc_comment)
                          : 0;
  std::string decl_file_in_project = declaration_file ? *declaration_file : "";
  const auto file__ = builder->CreateSharedString(decl_file_in_project);
  return reflection::CreateObject(
      *builder, name__, flds__, fixed, static_cast<int>(minalign),
      static_cast<int>(bytesize), attr__, docs__, file__);
}

bool StructDef::Deserialize(Parser &parser, const reflection::Object *object) {
  if (!DeserializeAttributes(parser, object->attributes())) return false;
  DeserializeDoc(doc_comment, object->documentation());
  name = parser.UnqualifiedName(object->name()->str());
  predecl = false;
  sortbysize = attributes.Lookup("original_order") == nullptr && !fixed;
  const auto &of = *(object->fields());
  auto indexes = std::vector<uoffset_t>(of.size());
  for (uoffset_t i = 0; i < of.size(); i++) indexes[of.Get(i)->id()] = i;
  size_t tmp_struct_size = 0;
  for (size_t i = 0; i < indexes.size(); i++) {
    auto field = of.Get(indexes[i]);
    auto field_def = new FieldDef();
    if (!field_def->Deserialize(parser, field) ||
        fields.Add(field_def->name, field_def)) {
      delete field_def;
      return false;
    }
    if (field_def->key) {
      if (has_key) {
        // only one field may be set as key
        delete field_def;
        return false;
      }
      has_key = true;
    }
    if (fixed) {
      // Recompute padding since that's currently not serialized.
      auto size = InlineSize(field_def->value.type);
      auto next_field =
          i + 1 < indexes.size() ? of.Get(indexes[i + 1]) : nullptr;
      tmp_struct_size += size;
      field_def->padding =
          next_field ? (next_field->offset() - field_def->value.offset) - size
                     : PaddingBytes(tmp_struct_size, minalign);
      tmp_struct_size += field_def->padding;
    }
  }
  FLATBUFFERS_ASSERT(static_cast<int>(tmp_struct_size) == object->bytesize());
  return true;
}

Offset<reflection::Field> FieldDef::Serialize(FlatBufferBuilder *builder,
                                              uint16_t id,
                                              const Parser &parser) const {
  auto name__ = builder->CreateString(name);
  auto type__ = value.type.Serialize(builder);
  auto attr__ = SerializeAttributes(builder, parser);
  auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                    ? builder->CreateVectorOfStrings(doc_comment)
                    : 0;
  double d;
  StringToNumber(value.constant.c_str(), &d);
  return reflection::CreateField(
      *builder, name__, type__, id, value.offset,
      // Is uint64>max(int64) tested?
      IsInteger(value.type.base_type) ? StringToInt(value.constant.c_str()) : 0,
      // result may be platform-dependent if underlying is float (not double)
      IsFloat(value.type.base_type) ? d : 0.0, deprecated, IsRequired(), key,
      attr__, docs__, IsOptional(), static_cast<uint16_t>(padding), offset64);
  // TODO: value.constant is almost always "0", we could save quite a bit of
  // space by sharing it. Same for common values of value.type.
}

bool FieldDef::Deserialize(Parser &parser, const reflection::Field *field) {
  name = field->name()->str();
  defined_namespace = parser.current_namespace_;
  if (!value.type.Deserialize(parser, field->type())) return false;
  value.offset = field->offset();
  if (IsInteger(value.type.base_type)) {
    value.constant = NumToString(field->default_integer());
  } else if (IsFloat(value.type.base_type)) {
    value.constant = FloatToString(field->default_real(), 17);
  }
  presence = FieldDef::MakeFieldPresence(field->optional(), field->required());
  padding = field->padding();
  key = field->key();
  offset64 = field->offset64();
  if (!DeserializeAttributes(parser, field->attributes())) return false;
  // TODO: this should probably be handled by a separate attribute
  if (attributes.Lookup("flexbuffer")) {
    flexbuffer = true;
    parser.uses_flexbuffers_ = true;
    if (value.type.base_type != BASE_TYPE_VECTOR ||
        value.type.element != BASE_TYPE_UCHAR)
      return false;
  }
  if (auto nested = attributes.Lookup("nested_flatbuffer")) {
    auto nested_qualified_name =
        parser.current_namespace_->GetFullyQualifiedName(nested->constant);
    nested_flatbuffer = parser.LookupStruct(nested_qualified_name);
    if (!nested_flatbuffer) return false;
  }
  shared = attributes.Lookup("shared") != nullptr;
  DeserializeDoc(doc_comment, field->documentation());
  return true;
}

Offset<reflection::RPCCall> RPCCall::Serialize(FlatBufferBuilder *builder,
                                               const Parser &parser) const {
  auto name__ = builder->CreateString(name);
  auto attr__ = SerializeAttributes(builder, parser);
  auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                    ? builder->CreateVectorOfStrings(doc_comment)
                    : 0;
  return reflection::CreateRPCCall(
      *builder, name__, request->serialized_location,
      response->serialized_location, attr__, docs__);
}

bool RPCCall::Deserialize(Parser &parser, const reflection::RPCCall *call) {
  name = call->name()->str();
  if (!DeserializeAttributes(parser, call->attributes())) return false;
  DeserializeDoc(doc_comment, call->documentation());
  request = parser.structs_.Lookup(call->request()->name()->str());
  response = parser.structs_.Lookup(call->response()->name()->str());
  if (!request || !response) { return false; }
  return true;
}

Offset<reflection::Service> ServiceDef::Serialize(FlatBufferBuilder *builder,
                                                  const Parser &parser) const {
  std::vector<Offset<reflection::RPCCall>> servicecall_offsets;
  for (auto it = calls.vec.begin(); it != calls.vec.end(); ++it) {
    servicecall_offsets.push_back((*it)->Serialize(builder, parser));
  }
  const auto qualified_name = defined_namespace->GetFullyQualifiedName(name);
  const auto name__ = builder->CreateString(qualified_name);
  const auto call__ = builder->CreateVector(servicecall_offsets);
  const auto attr__ = SerializeAttributes(builder, parser);
  const auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                          ? builder->CreateVectorOfStrings(doc_comment)
                          : 0;
  std::string decl_file_in_project = declaration_file ? *declaration_file : "";
  const auto file__ = builder->CreateSharedString(decl_file_in_project);
  return reflection::CreateService(*builder, name__, call__, attr__, docs__,
                                   file__);
}

bool ServiceDef::Deserialize(Parser &parser,
                             const reflection::Service *service) {
  name = parser.UnqualifiedName(service->name()->str());
  if (service->calls()) {
    for (uoffset_t i = 0; i < service->calls()->size(); ++i) {
      auto call = new RPCCall();
      if (!call->Deserialize(parser, service->calls()->Get(i)) ||
          calls.Add(call->name, call)) {
        delete call;
        return false;
      }
    }
  }
  if (!DeserializeAttributes(parser, service->attributes())) return false;
  DeserializeDoc(doc_comment, service->documentation());
  return true;
}

Offset<reflection::Enum> EnumDef::Serialize(FlatBufferBuilder *builder,
                                            const Parser &parser) const {
  std::vector<Offset<reflection::EnumVal>> enumval_offsets;
  for (auto it = vals.vec.begin(); it != vals.vec.end(); ++it) {
    enumval_offsets.push_back((*it)->Serialize(builder, parser));
  }
  const auto qualified_name = defined_namespace->GetFullyQualifiedName(name);
  const auto name__ = builder->CreateString(qualified_name);
  const auto vals__ = builder->CreateVector(enumval_offsets);
  const auto type__ = underlying_type.Serialize(builder);
  const auto attr__ = SerializeAttributes(builder, parser);
  const auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                          ? builder->CreateVectorOfStrings(doc_comment)
                          : 0;
  std::string decl_file_in_project = declaration_file ? *declaration_file : "";
  const auto file__ = builder->CreateSharedString(decl_file_in_project);
  return reflection::CreateEnum(*builder, name__, vals__, is_union, type__,
                                attr__, docs__, file__);
}

bool EnumDef::Deserialize(Parser &parser, const reflection::Enum *_enum) {
  name = parser.UnqualifiedName(_enum->name()->str());
  for (uoffset_t i = 0; i < _enum->values()->size(); ++i) {
    auto val = new EnumVal();
    if (!val->Deserialize(parser, _enum->values()->Get(i)) ||
        vals.Add(val->name, val)) {
      delete val;
      return false;
    }
  }
  is_union = _enum->is_union();
  if (!underlying_type.Deserialize(parser, _enum->underlying_type())) {
    return false;
  }
  if (!DeserializeAttributes(parser, _enum->attributes())) return false;
  DeserializeDoc(doc_comment, _enum->documentation());
  return true;
}

flatbuffers::Offset<
    flatbuffers::Vector<flatbuffers::Offset<reflection::KeyValue>>>
EnumVal::SerializeAttributes(FlatBufferBuilder *builder,
                             const Parser &parser) const {
  return SerializeAttributesCommon(attributes, builder, parser);
}

bool EnumVal::DeserializeAttributes(
    Parser &parser, const Vector<Offset<reflection::KeyValue>> *attrs) {
  return DeserializeAttributesCommon(attributes, parser, attrs);
}

Offset<reflection::EnumVal> EnumVal::Serialize(FlatBufferBuilder *builder,
                                               const Parser &parser) const {
  const auto name__ = builder->CreateString(name);
  const auto type__ = union_type.Serialize(builder);
  const auto attr__ = SerializeAttributes(builder, parser);
  const auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                          ? builder->CreateVectorOfStrings(doc_comment)
                          : 0;
  return reflection::CreateEnumVal(*builder, name__, value, type__, docs__,
                                   attr__);
}

bool EnumVal::Deserialize(Parser &parser, const reflection::EnumVal *val) {
  name = val->name()->str();
  value = val->value();
  if (!union_type.Deserialize(parser, val->union_type())) return false;
  if (!DeserializeAttributes(parser, val->attributes())) return false;
  DeserializeDoc(doc_comment, val->documentation());
  return true;
}

Offset<reflection::Type> Type::Serialize(FlatBufferBuilder *builder) const {
  size_t element_size = SizeOf(element);
  if (base_type == BASE_TYPE_VECTOR && element == BASE_TYPE_STRUCT &&
      struct_def->bytesize != 0) {
    // struct_def->bytesize==0 means struct is table
    element_size = struct_def->bytesize;
  }
  return reflection::CreateType(
      *builder, static_cast<reflection::BaseType>(base_type),
      static_cast<reflection::BaseType>(element),
      struct_def ? struct_def->index : (enum_def ? enum_def->index : -1),
      fixed_length, static_cast<uint32_t>(SizeOf(base_type)),
      static_cast<uint32_t>(element_size));
}

bool Type::Deserialize(const Parser &parser, const reflection::Type *type) {
  if (type == nullptr) return true;
  base_type = static_cast<BaseType>(type->base_type());
  element = static_cast<BaseType>(type->element());
  fixed_length = type->fixed_length();
  if (type->index() >= 0) {
    bool is_series = type->base_type() == reflection::Vector ||
                     type->base_type() == reflection::Array;
    if (type->base_type() == reflection::Obj ||
        (is_series && type->element() == reflection::Obj)) {
      if (static_cast<size_t>(type->index()) < parser.structs_.vec.size()) {
        struct_def = parser.structs_.vec[type->index()];
        struct_def->refcount++;
      } else {
        return false;
      }
    } else {
      if (static_cast<size_t>(type->index()) < parser.enums_.vec.size()) {
        enum_def = parser.enums_.vec[type->index()];
      } else {
        return false;
      }
    }
  }
  return true;
}

flatbuffers::Offset<
    flatbuffers::Vector<flatbuffers::Offset<reflection::KeyValue>>>
Definition::SerializeAttributes(FlatBufferBuilder *builder,
                                const Parser &parser) const {
  return SerializeAttributesCommon(attributes, builder, parser);
}

bool Definition::DeserializeAttributes(
    Parser &parser, const Vector<Offset<reflection::KeyValue>> *attrs) {
  return DeserializeAttributesCommon(attributes, parser, attrs);
}

/************************************************************************/
/* DESERIALIZATION                                                      */
/************************************************************************/
bool Parser::Deserialize(const uint8_t *buf, const size_t size) {
  flatbuffers::Verifier verifier(reinterpret_cast<const uint8_t *>(buf), size);
  bool size_prefixed = false;
  if (!reflection::SchemaBufferHasIdentifier(buf)) {
    if (!flatbuffers::BufferHasIdentifier(buf, reflection::SchemaIdentifier(),
                                          true))
      return false;
    else
      size_prefixed = true;
  }
  auto verify_fn = size_prefixed ? &reflection::VerifySizePrefixedSchemaBuffer
                                 : &reflection::VerifySchemaBuffer;
  if (!verify_fn(verifier)) { return false; }
  auto schema = size_prefixed ? reflection::GetSizePrefixedSchema(buf)
                              : reflection::GetSchema(buf);
  return Deserialize(schema);
}

bool Parser::Deserialize(const reflection::Schema *schema) {
  file_identifier_ = schema->file_ident() ? schema->file_ident()->str() : "";
  file_extension_ = schema->file_ext() ? schema->file_ext()->str() : "";
  std::map<std::string, Namespace *> namespaces_index;

  // Create defs without deserializing so references from fields to structs and
  // enums can be resolved.
  for (auto it = schema->objects()->begin(); it != schema->objects()->end();
       ++it) {
    auto struct_def = new StructDef();
    struct_def->bytesize = it->bytesize();
    struct_def->fixed = it->is_struct();
    struct_def->minalign = it->minalign();
    if (structs_.Add(it->name()->str(), struct_def)) {
      delete struct_def;
      return false;
    }
    auto type = new Type(BASE_TYPE_STRUCT, struct_def, nullptr);
    if (types_.Add(it->name()->str(), type)) {
      delete type;
      return false;
    }
  }
  for (auto it = schema->enums()->begin(); it != schema->enums()->end(); ++it) {
    auto enum_def = new EnumDef();
    if (enums_.Add(it->name()->str(), enum_def)) {
      delete enum_def;
      return false;
    }
    auto type = new Type(BASE_TYPE_UNION, nullptr, enum_def);
    if (types_.Add(it->name()->str(), type)) {
      delete type;
      return false;
    }
  }

  // Now fields can refer to structs and enums by index.
  for (auto it = schema->objects()->begin(); it != schema->objects()->end();
       ++it) {
    std::string qualified_name = it->name()->str();
    auto struct_def = structs_.Lookup(qualified_name);
    struct_def->defined_namespace =
        GetNamespace(qualified_name, namespaces_, namespaces_index);
    if (!struct_def->Deserialize(*this, *it)) { return false; }
    if (schema->root_table() == *it) { root_struct_def_ = struct_def; }
  }
  for (auto it = schema->enums()->begin(); it != schema->enums()->end(); ++it) {
    std::string qualified_name = it->name()->str();
    auto enum_def = enums_.Lookup(qualified_name);
    enum_def->defined_namespace =
        GetNamespace(qualified_name, namespaces_, namespaces_index);
    if (!enum_def->Deserialize(*this, *it)) { return false; }
  }

  if (schema->services()) {
    for (auto it = schema->services()->begin(); it != schema->services()->end();
         ++it) {
      std::string qualified_name = it->name()->str();
      auto service_def = new ServiceDef();
      service_def->defined_namespace =
          GetNamespace(qualified_name, namespaces_, namespaces_index);
      if (!service_def->Deserialize(*this, *it) ||
          services_.Add(qualified_name, service_def)) {
        delete service_def;
        return false;
      }
    }
  }
  advanced_features_ = schema->advanced_features();

  if (schema->fbs_files())
    for (auto s = schema->fbs_files()->begin(); s != schema->fbs_files()->end();
         ++s) {
      for (auto f = s->included_filenames()->begin();
           f != s->included_filenames()->end(); ++f) {
        IncludedFile included_file;
        included_file.filename = f->str();
        files_included_per_file_[s->filename()->str()].insert(included_file);
      }
    }

  return true;
}

std::string Parser::ConformTo(const Parser &base) {
  for (auto sit = structs_.vec.begin(); sit != structs_.vec.end(); ++sit) {
    auto &struct_def = **sit;
    auto qualified_name =
        struct_def.defined_namespace->GetFullyQualifiedName(struct_def.name);
    auto struct_def_base = base.LookupStruct(qualified_name);
    if (!struct_def_base) continue;
    std::set<FieldDef *> renamed_fields;
    for (auto fit = struct_def.fields.vec.begin();
         fit != struct_def.fields.vec.end(); ++fit) {
      auto &field = **fit;
      auto field_base = struct_def_base->fields.Lookup(field.name);
      const auto qualified_field_name = qualified_name + "." + field.name;
      if (field_base) {
        if (field.value.offset != field_base->value.offset) {
          return "offsets differ for field: " + qualified_field_name;
        }
        if (field.value.constant != field_base->value.constant) {
          return "defaults differ for field: " + qualified_field_name;
        }
        if (!EqualByName(field.value.type, field_base->value.type)) {
          return "types differ for field: " + qualified_field_name;
        }
        if (field.offset64 != field_base->offset64) {
          return "offset types differ for field: " + qualified_field_name;
        }
      } else {
        // Doesn't have to exist, deleting fields is fine.
        // But we should check if there is a field that has the same offset
        // but is incompatible (in the case of field renaming).
        for (auto fbit = struct_def_base->fields.vec.begin();
             fbit != struct_def_base->fields.vec.end(); ++fbit) {
          field_base = *fbit;
          if (field.value.offset == field_base->value.offset) {
            renamed_fields.insert(field_base);
            if (!EqualByName(field.value.type, field_base->value.type)) {
              const auto qualified_field_base =
                  qualified_name + "." + field_base->name;
              return "field renamed to different type: " +
                     qualified_field_name + " (renamed from " +
                     qualified_field_base + ")";
            }
            break;
          }
        }
      }
    }
    // deletion of trailing fields are not allowed
    for (auto fit = struct_def_base->fields.vec.begin();
         fit != struct_def_base->fields.vec.end(); ++fit) {
      auto &field_base = **fit;
      // not a renamed field
      if (renamed_fields.find(&field_base) == renamed_fields.end()) {
        auto field = struct_def.fields.Lookup(field_base.name);
        if (!field) {
          return "field deleted: " + qualified_name + "." + field_base.name;
        }
      }
    }
  }

  for (auto eit = enums_.vec.begin(); eit != enums_.vec.end(); ++eit) {
    auto &enum_def = **eit;
    auto qualified_name =
        enum_def.defined_namespace->GetFullyQualifiedName(enum_def.name);
    auto enum_def_base = base.enums_.Lookup(qualified_name);
    if (!enum_def_base) continue;
    for (auto evit = enum_def.Vals().begin(); evit != enum_def.Vals().end();
         ++evit) {
      auto &enum_val = **evit;
      auto enum_val_base = enum_def_base->Lookup(enum_val.name);
      if (enum_val_base) {
        if (enum_val != *enum_val_base)
          return "values differ for enum: " + enum_val.name;
      }
    }
    // Check underlying type changes
    if (enum_def_base->underlying_type.base_type != enum_def.underlying_type.base_type) {
      return "underlying type differ for " + std::string(enum_def.is_union ? "union: " : "enum: ") + qualified_name;
    }
  }
  return "";
}

}  // namespace flatbuffers