aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/tools/bison/lib/unistr/u8-mbtoucr.c
blob: afc43b6a49d074958d29b014d39a3fb66e5bb0aa (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
/* Look at first character in UTF-8 string, returning an error code.
   Copyright (C) 1999-2002, 2006-2007, 2009-2020 Free Software Foundation, Inc.
   Written by Bruno Haible <bruno@clisp.org>, 2001.

   This program is free software: you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published
   by the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include "unistr.h"

int
u8_mbtoucr (ucs4_t *puc, const uint8_t *s, size_t n)
{
  uint8_t c = *s;

  if (c < 0x80)
    {
      *puc = c;
      return 1;
    }
  else if (c >= 0xc2)
    {
      if (c < 0xe0)
        {
          if (n >= 2)
            {
              if ((s[1] ^ 0x80) < 0x40)
                {
                  *puc = ((unsigned int) (c & 0x1f) << 6)
                         | (unsigned int) (s[1] ^ 0x80);
                  return 2;
                }
              /* invalid multibyte character */
            }
          else
            {
              /* incomplete multibyte character */
              *puc = 0xfffd;
              return -2;
            }
        }
      else if (c < 0xf0)
        {
          if (n >= 2)
            {
              if ((s[1] ^ 0x80) < 0x40
                  && (c >= 0xe1 || s[1] >= 0xa0)
                  && (c != 0xed || s[1] < 0xa0))
                {
                  if (n >= 3)
                    {
                      if ((s[2] ^ 0x80) < 0x40)
                        {
                          *puc = ((unsigned int) (c & 0x0f) << 12)
                                 | ((unsigned int) (s[1] ^ 0x80) << 6)
                                 | (unsigned int) (s[2] ^ 0x80);
                          return 3;
                        }
                      /* invalid multibyte character */
                    }
                  else
                    {
                      /* incomplete multibyte character */
                      *puc = 0xfffd;
                      return -2;
                    }
                }
              /* invalid multibyte character */
            }
          else
            {
              /* incomplete multibyte character */
              *puc = 0xfffd;
              return -2;
            }
        }
      else if (c < 0xf8)
        {
          if (n >= 2)
            {
              if ((s[1] ^ 0x80) < 0x40
                  && (c >= 0xf1 || s[1] >= 0x90)
                  && (c < 0xf4 || (c == 0xf4 && s[1] < 0x90)))
                {
                  if (n >= 3)
                    {
                      if ((s[2] ^ 0x80) < 0x40)
                        {
                          if (n >= 4)
                            {
                              if ((s[3] ^ 0x80) < 0x40)
                                {
                                  *puc = ((unsigned int) (c & 0x07) << 18)
                                         | ((unsigned int) (s[1] ^ 0x80) << 12)
                                         | ((unsigned int) (s[2] ^ 0x80) << 6)
                                         | (unsigned int) (s[3] ^ 0x80);
                                  return 4;
                                }
                              /* invalid multibyte character */
                            }
                          else
                            {
                              /* incomplete multibyte character */
                              *puc = 0xfffd;
                              return -2;
                            }
                        }
                      /* invalid multibyte character */
                    }
                  else
                    {
                      /* incomplete multibyte character */
                      *puc = 0xfffd;
                      return -2;
                    }
                }
              /* invalid multibyte character */
            }
          else
            {
              /* incomplete multibyte character */
              *puc = 0xfffd;
              return -2;
            }
        }
    }
  /* invalid multibyte character */
  *puc = 0xfffd;
  return -1;
}