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
|
/* Copyright (c) 2021 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
#include <cassert>
#include <cstdint>
#include "support/Utf8.h"
#include "support/Unicode.h"
// The below implementation is based off of https://github.com/google/cel-cpp/internal/utf8.cc,
// which is itself based off of https://go.googlesource.com/go/+/refs/heads/master/src/unicode/utf8/utf8.go.
// If for some reason you feel the need to copy this implementation, please retain a comment
// referencing the two source files and giving credit, as well as maintaining any and all
// obligations required by the BSD 3-clause license that governs this file.
namespace antlrcpp {
namespace {
#undef SELF
constexpr uint8_t SELF = 0x80;
#undef LOW
constexpr uint8_t LOW = 0x80;
#undef HIGH
constexpr uint8_t HIGH = 0xbf;
#undef MASKX
constexpr uint8_t MASKX = 0x3f;
#undef MASK2
constexpr uint8_t MASK2 = 0x1f;
#undef MASK3
constexpr uint8_t MASK3 = 0xf;
#undef MASK4
constexpr uint8_t MASK4 = 0x7;
#undef TX
constexpr uint8_t TX = 0x80;
#undef T2
constexpr uint8_t T2 = 0xc0;
#undef T3
constexpr uint8_t T3 = 0xe0;
#undef T4
constexpr uint8_t T4 = 0xf0;
#undef XX
constexpr uint8_t XX = 0xf1;
#undef AS
constexpr uint8_t AS = 0xf0;
#undef S1
constexpr uint8_t S1 = 0x02;
#undef S2
constexpr uint8_t S2 = 0x13;
#undef S3
constexpr uint8_t S3 = 0x03;
#undef S4
constexpr uint8_t S4 = 0x23;
#undef S5
constexpr uint8_t S5 = 0x34;
#undef S6
constexpr uint8_t S6 = 0x04;
#undef S7
constexpr uint8_t S7 = 0x44;
// NOLINTBEGIN
// clang-format off
#undef LEADING
constexpr uint8_t LEADING[256] = {
// 1 2 3 4 5 6 7 8 9 A B C D E F
AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x00-0x0F
AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x10-0x1F
AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x20-0x2F
AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x30-0x3F
AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x40-0x4F
AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x50-0x5F
AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x60-0x6F
AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x70-0x7F
// 1 2 3 4 5 6 7 8 9 A B C D E F
XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0x80-0x8F
XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0x90-0x9F
XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0xA0-0xAF
XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0xB0-0xBF
XX, XX, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, // 0xC0-0xCF
S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, // 0xD0-0xDF
S2, S3, S3, S3, S3, S3, S3, S3, S3, S3, S3, S3, S3, S4, S3, S3, // 0xE0-0xEF
S5, S6, S6, S6, S7, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0xF0-0xFF
};
// clang-format on
// NOLINTEND
#undef ACCEPT
constexpr std::pair<uint8_t, uint8_t> ACCEPT[16] = {
{LOW, HIGH}, {0xa0, HIGH}, {LOW, 0x9f}, {0x90, HIGH},
{LOW, 0x8f}, {0x0, 0x0}, {0x0, 0x0}, {0x0, 0x0},
{0x0, 0x0}, {0x0, 0x0}, {0x0, 0x0}, {0x0, 0x0},
{0x0, 0x0}, {0x0, 0x0}, {0x0, 0x0}, {0x0, 0x0},
};
} // namespace
std::pair<char32_t, size_t> Utf8::decode(std::string_view input) {
assert(!input.empty());
const auto b = static_cast<uint8_t>(input.front());
input.remove_prefix(1);
if (b < SELF) {
return {static_cast<char32_t>(b), 1};
}
const auto leading = LEADING[b];
if (leading == XX) {
return {Unicode::REPLACEMENT_CHARACTER, 1};
}
auto size = static_cast<size_t>(leading & 7) - 1;
if (size > input.size()) {
return {Unicode::REPLACEMENT_CHARACTER, 1};
}
const auto& accept = ACCEPT[leading >> 4];
const auto b1 = static_cast<uint8_t>(input.front());
input.remove_prefix(1);
if (b1 < accept.first || b1 > accept.second) {
return {Unicode::REPLACEMENT_CHARACTER, 1};
}
if (size <= 1) {
return {(static_cast<char32_t>(b & MASK2) << 6) |
static_cast<char32_t>(b1 & MASKX),
2};
}
const auto b2 = static_cast<uint8_t>(input.front());
input.remove_prefix(1);
if (b2 < LOW || b2 > HIGH) {
return {Unicode::REPLACEMENT_CHARACTER, 1};
}
if (size <= 2) {
return {(static_cast<char32_t>(b & MASK3) << 12) |
(static_cast<char32_t>(b1 & MASKX) << 6) |
static_cast<char32_t>(b2 & MASKX),
3};
}
const auto b3 = static_cast<uint8_t>(input.front());
input.remove_prefix(1);
if (b3 < LOW || b3 > HIGH) {
return {Unicode::REPLACEMENT_CHARACTER, 1};
}
return {(static_cast<char32_t>(b & MASK4) << 18) |
(static_cast<char32_t>(b1 & MASKX) << 12) |
(static_cast<char32_t>(b2 & MASKX) << 6) |
static_cast<char32_t>(b3 & MASKX),
4};
}
std::optional<std::u32string> Utf8::strictDecode(std::string_view input) {
std::u32string output;
char32_t codePoint;
size_t codeUnits;
output.reserve(input.size()); // Worst case is each byte is a single Unicode code point.
for (size_t index = 0; index < input.size(); index += codeUnits) {
std::tie(codePoint, codeUnits) = Utf8::decode(input.substr(index));
if (codePoint == Unicode::REPLACEMENT_CHARACTER && codeUnits == 1) {
// Condition is only met when an illegal byte sequence is encountered. See Utf8::decode.
return std::nullopt;
}
output.push_back(codePoint);
}
output.shrink_to_fit();
return output;
}
std::u32string Utf8::lenientDecode(std::string_view input) {
std::u32string output;
char32_t codePoint;
size_t codeUnits;
output.reserve(input.size()); // Worst case is each byte is a single Unicode code point.
for (size_t index = 0; index < input.size(); index += codeUnits) {
std::tie(codePoint, codeUnits) = Utf8::decode(input.substr(index));
output.push_back(codePoint);
}
output.shrink_to_fit();
return output;
}
std::string& Utf8::encode(std::string* buffer, char32_t codePoint) {
assert(buffer != nullptr);
if (!Unicode::isValid(codePoint)) {
codePoint = Unicode::REPLACEMENT_CHARACTER;
}
if (codePoint <= 0x7f) {
buffer->push_back(static_cast<char>(static_cast<uint8_t>(codePoint)));
} else if (codePoint <= 0x7ff) {
buffer->push_back(
static_cast<char>(T2 | static_cast<uint8_t>(codePoint >> 6)));
buffer->push_back(
static_cast<char>(TX | (static_cast<uint8_t>(codePoint) & MASKX)));
} else if (codePoint <= 0xffff) {
buffer->push_back(
static_cast<char>(T3 | static_cast<uint8_t>(codePoint >> 12)));
buffer->push_back(static_cast<char>(
TX | (static_cast<uint8_t>(codePoint >> 6) & MASKX)));
buffer->push_back(
static_cast<char>(TX | (static_cast<uint8_t>(codePoint) & MASKX)));
} else {
buffer->push_back(
static_cast<char>(T4 | static_cast<uint8_t>(codePoint >> 18)));
buffer->push_back(static_cast<char>(
TX | (static_cast<uint8_t>(codePoint >> 12) & MASKX)));
buffer->push_back(static_cast<char>(
TX | (static_cast<uint8_t>(codePoint >> 6) & MASKX)));
buffer->push_back(
static_cast<char>(TX | (static_cast<uint8_t>(codePoint) & MASKX)));
}
return *buffer;
}
std::optional<std::string> Utf8::strictEncode(std::u32string_view input) {
std::string output;
output.reserve(input.size() * 4); // Worst case is each Unicode code point encodes to 4 bytes.
for (size_t index = 0; index < input.size(); index++) {
char32_t codePoint = input[index];
if (!Unicode::isValid(codePoint)) {
return std::nullopt;
}
Utf8::encode(&output, codePoint);
}
output.shrink_to_fit();
return output;
}
std::string Utf8::lenientEncode(std::u32string_view input) {
std::string output;
output.reserve(input.size() * 4); // Worst case is each Unicode code point encodes to 4 bytes.
for (size_t index = 0; index < input.size(); index++) {
char32_t codePoint = input[index];
if (!Unicode::isValid(codePoint)) {
codePoint = Unicode::REPLACEMENT_CHARACTER;
}
Utf8::encode(&output, codePoint);
}
output.shrink_to_fit();
return output;
}
}
|
