File: Unicode.cpp

package info (click to toggle)
android-platform-tools 34.0.5-12
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 150,900 kB
  • sloc: cpp: 805,786; java: 293,500; ansic: 128,288; xml: 127,491; python: 41,481; sh: 14,245; javascript: 9,665; cs: 3,846; asm: 2,049; makefile: 1,917; yacc: 440; awk: 368; ruby: 183; sql: 140; perl: 88; lex: 67
file content (541 lines) | stat: -rw-r--r-- 16,607 bytes parent folder | download | duplicates (2)
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
/*
 * Copyright (C) 2005 The Android Open Source Project
 *
 * 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.
 */

#define LOG_TAG "unicode"

#include <android-base/macros.h>
#include <limits.h>
#include <utils/Unicode.h>

#include <log/log.h>

extern "C" {

static const char32_t kByteMask = 0x000000BF;
static const char32_t kByteMark = 0x00000080;

// Surrogates aren't valid for UTF-32 characters, so define some
// constants that will let us screen them out.
static const char32_t kUnicodeSurrogateHighStart  = 0x0000D800;
// Unused, here for completeness:
// static const char32_t kUnicodeSurrogateHighEnd = 0x0000DBFF;
// static const char32_t kUnicodeSurrogateLowStart = 0x0000DC00;
static const char32_t kUnicodeSurrogateLowEnd     = 0x0000DFFF;
static const char32_t kUnicodeSurrogateStart      = kUnicodeSurrogateHighStart;
static const char32_t kUnicodeSurrogateEnd        = kUnicodeSurrogateLowEnd;
static const char32_t kUnicodeMaxCodepoint        = 0x0010FFFF;

// Mask used to set appropriate bits in first byte of UTF-8 sequence,
// indexed by number of bytes in the sequence.
// 0xxxxxxx
// -> (00-7f) 7bit. Bit mask for the first byte is 0x00000000
// 110yyyyx 10xxxxxx
// -> (c0-df)(80-bf) 11bit. Bit mask is 0x000000C0
// 1110yyyy 10yxxxxx 10xxxxxx
// -> (e0-ef)(80-bf)(80-bf) 16bit. Bit mask is 0x000000E0
// 11110yyy 10yyxxxx 10xxxxxx 10xxxxxx
// -> (f0-f7)(80-bf)(80-bf)(80-bf) 21bit. Bit mask is 0x000000F0
static const char32_t kFirstByteMark[] = {
    0x00000000, 0x00000000, 0x000000C0, 0x000000E0, 0x000000F0
};

// --------------------------------------------------------------------------
// UTF-32
// --------------------------------------------------------------------------

/**
 * Return number of UTF-8 bytes required for the character. If the character
 * is invalid, return size of 0.
 */
static inline size_t utf32_codepoint_utf8_length(char32_t srcChar)
{
    // Figure out how many bytes the result will require.
    if (srcChar < 0x00000080) {
        return 1;
    } else if (srcChar < 0x00000800) {
        return 2;
    } else if (srcChar < 0x00010000) {
        if ((srcChar < kUnicodeSurrogateStart) || (srcChar > kUnicodeSurrogateEnd)) {
            return 3;
        } else {
            // Surrogates are invalid UTF-32 characters.
            return 0;
        }
    }
    // Max code point for Unicode is 0x0010FFFF.
    else if (srcChar <= kUnicodeMaxCodepoint) {
        return 4;
    } else {
        // Invalid UTF-32 character.
        return 0;
    }
}

// Write out the source character to <dstP>.

static inline void utf32_codepoint_to_utf8(uint8_t* dstP, char32_t srcChar, size_t bytes)
{
    dstP += bytes;
    switch (bytes)
    {   /* note: everything falls through. */
        case 4: *--dstP = (uint8_t)((srcChar | kByteMark) & kByteMask); srcChar >>= 6;
            FALLTHROUGH_INTENDED;
        case 3: *--dstP = (uint8_t)((srcChar | kByteMark) & kByteMask); srcChar >>= 6;
            FALLTHROUGH_INTENDED;
        case 2: *--dstP = (uint8_t)((srcChar | kByteMark) & kByteMask); srcChar >>= 6;
            FALLTHROUGH_INTENDED;
        case 1: *--dstP = (uint8_t)(srcChar | kFirstByteMark[bytes]);
    }
}

static inline int32_t utf32_at_internal(const char* cur, size_t *num_read)
{
    const char first_char = *cur;
    if ((first_char & 0x80) == 0) { // ASCII
        *num_read = 1;
        return *cur;
    }
    cur++;
    char32_t mask, to_ignore_mask;
    size_t num_to_read = 0;
    char32_t utf32 = first_char;
    for (num_to_read = 1, mask = 0x40, to_ignore_mask = 0xFFFFFF80;
         (first_char & mask);
         num_to_read++, to_ignore_mask |= mask, mask >>= 1) {
        // 0x3F == 00111111
        utf32 = (utf32 << 6) + (*cur++ & 0x3F);
    }
    to_ignore_mask |= mask;
    utf32 &= ~(to_ignore_mask << (6 * (num_to_read - 1)));

    *num_read = num_to_read;
    return static_cast<int32_t>(utf32);
}

int32_t utf32_from_utf8_at(const char *src, size_t src_len, size_t index, size_t *next_index)
{
    if (index >= src_len) {
        return -1;
    }
    size_t unused_index;
    if (next_index == nullptr) {
        next_index = &unused_index;
    }
    size_t num_read;
    int32_t ret = utf32_at_internal(src + index, &num_read);
    if (ret >= 0) {
        *next_index = index + num_read;
    }

    return ret;
}

ssize_t utf32_to_utf8_length(const char32_t *src, size_t src_len)
{
    if (src == nullptr || src_len == 0) {
        return -1;
    }

    size_t ret = 0;
    const char32_t *end = src + src_len;
    while (src < end) {
        size_t char_len = utf32_codepoint_utf8_length(*src++);
        if (SSIZE_MAX - char_len < ret) {
            // If this happens, we would overflow the ssize_t type when
            // returning from this function, so we cannot express how
            // long this string is in an ssize_t.
            android_errorWriteLog(0x534e4554, "37723026");
            return -1;
        }
        ret += char_len;
    }
    return ret;
}

void utf32_to_utf8(const char32_t* src, size_t src_len, char* dst, size_t dst_len)
{
    if (src == nullptr || src_len == 0 || dst == nullptr) {
        return;
    }

    const char32_t *cur_utf32 = src;
    const char32_t *end_utf32 = src + src_len;
    char *cur = dst;
    while (cur_utf32 < end_utf32) {
        size_t len = utf32_codepoint_utf8_length(*cur_utf32);
        LOG_ALWAYS_FATAL_IF(dst_len < len, "%zu < %zu", dst_len, len);
        utf32_codepoint_to_utf8((uint8_t *)cur, *cur_utf32++, len);
        cur += len;
        dst_len -= len;
    }
    LOG_ALWAYS_FATAL_IF(dst_len < 1, "dst_len < 1: %zu < 1", dst_len);
    *cur = '\0';
}

// --------------------------------------------------------------------------
// UTF-16
// --------------------------------------------------------------------------

int strcmp16(const char16_t *s1, const char16_t *s2)
{
  char16_t ch;
  int d = 0;

  while ( 1 ) {
    d = (int)(ch = *s1++) - (int)*s2++;
    if ( d || !ch )
      break;
  }

  return d;
}

int strncmp16(const char16_t *s1, const char16_t *s2, size_t n)
{
  char16_t ch;
  int d = 0;

  if (n == 0) {
    return 0;
  }

  do {
    d = (int)(ch = *s1++) - (int)*s2++;
    if ( d || !ch ) {
      break;
    }
  } while (--n);

  return d;
}

size_t strlen16(const char16_t *s)
{
  const char16_t *ss = s;
  while ( *ss )
    ss++;
  return ss-s;
}

size_t strnlen16(const char16_t *s, size_t maxlen)
{
  const char16_t *ss = s;

  /* Important: the maxlen test must precede the reference through ss;
     since the byte beyond the maximum may segfault */
  while ((maxlen > 0) && *ss) {
    ss++;
    maxlen--;
  }
  return ss-s;
}

char16_t* strstr16(const char16_t* src, const char16_t* target)
{
    const char16_t needle = *target;
    if (needle == '\0') return (char16_t*)src;

    const size_t target_len = strlen16(++target);
    do {
        do {
            if (*src == '\0') {
                return nullptr;
            }
        } while (*src++ != needle);
    } while (strncmp16(src, target, target_len) != 0);
    src--;

    return (char16_t*)src;
}

int strzcmp16(const char16_t *s1, size_t n1, const char16_t *s2, size_t n2)
{
    const char16_t* e1 = s1+n1;
    const char16_t* e2 = s2+n2;

    while (s1 < e1 && s2 < e2) {
        const int d = (int)*s1++ - (int)*s2++;
        if (d) {
            return d;
        }
    }

    return n1 < n2
        ? (0 - (int)*s2)
        : (n1 > n2
           ? ((int)*s1 - 0)
           : 0);
}

// is_any_surrogate() returns true if w is either a high or low surrogate
static constexpr bool is_any_surrogate(char16_t w) {
    return (w & 0xf800) == 0xd800;
}

// is_surrogate_pair() returns true if w1 and w2 form a valid surrogate pair
static constexpr bool is_surrogate_pair(char16_t w1, char16_t w2) {
    return ((w1 & 0xfc00) == 0xd800) && ((w2 & 0xfc00) == 0xdc00);
}

// TODO: currently utf16_to_utf8_length() returns -1 if src_len == 0,
// which is inconsistent with utf8_to_utf16_length(), here we keep the
// current behavior as intended not to break compatibility
ssize_t utf16_to_utf8_length(const char16_t *src, size_t src_len)
{
    if (src == nullptr || src_len == 0)
        return -1;

    const char16_t* const end = src + src_len;
    const char16_t* in = src;
    size_t utf8_len = 0;

    while (in < end) {
        char16_t w = *in++;
        if (LIKELY(w < 0x0080)) {
            utf8_len += 1;
            continue;
        }
        if (LIKELY(w < 0x0800)) {
            utf8_len += 2;
            continue;
        }
        if (LIKELY(!is_any_surrogate(w))) {
            utf8_len += 3;
            continue;
        }
        if (in < end && is_surrogate_pair(w, *in)) {
            utf8_len += 4;
            in++;
            continue;
        }
        /* skip if at the end of the string or invalid surrogate pair */
    }
    return (in == end && utf8_len < SSIZE_MAX) ? utf8_len : -1;
}

void utf16_to_utf8(const char16_t* src, size_t src_len, char* dst, size_t dst_len)
{
    if (src == nullptr || src_len == 0 || dst == nullptr) {
        return;
    }

    const char16_t* in = src;
    const char16_t* const in_end = src + src_len;
    char* out = dst;
    const char* const out_end = dst + dst_len;
    char16_t w2;

    auto err_out = [&out, &out_end, &dst_len]() {
        LOG_ALWAYS_FATAL_IF(out >= out_end,
                "target utf8 string size %zu too short", dst_len);
    };

    while (in < in_end) {
        char16_t w = *in++;
        if (LIKELY(w < 0x0080)) {
            if (out + 1 > out_end)
                return err_out();
            *out++ = (char)(w & 0xff);
            continue;
        }
        if (LIKELY(w < 0x0800)) {
            if (out + 2 > out_end)
                return err_out();
            *out++ = (char)(0xc0 | ((w >> 6) & 0x1f));
            *out++ = (char)(0x80 | ((w >> 0) & 0x3f));
            continue;
        }
        if (LIKELY(!is_any_surrogate(w))) {
            if (out + 3 > out_end)
                return err_out();
            *out++ = (char)(0xe0 | ((w >> 12) & 0xf));
            *out++ = (char)(0x80 | ((w >> 6) & 0x3f));
            *out++ = (char)(0x80 | ((w >> 0) & 0x3f));
            continue;
        }
        /* surrogate pair */
        if (in < in_end && (w2 = *in, is_surrogate_pair(w, w2))) {
            if (out + 4 > out_end)
                return err_out();
            char32_t dw = (char32_t)(0x10000 + ((w - 0xd800) << 10) + (w2 - 0xdc00));
            *out++ = (char)(0xf0 | ((dw >> 18) & 0x07));
            *out++ = (char)(0x80 | ((dw >> 12) & 0x3f));
            *out++ = (char)(0x80 | ((dw >> 6)  & 0x3f));
            *out++ = (char)(0x80 | ((dw >> 0)  & 0x3f));
            in++;
        }
        /* We reach here in two cases:
         *  1) (in == in_end), which means end of the input string
         *  2) (w2 & 0xfc00) != 0xdc00, which means invalid surrogate pair
         * In either case, we intentionally do nothing and skip
         */
    }
    *out = '\0';
    return;
}

// --------------------------------------------------------------------------
// UTF-8
// --------------------------------------------------------------------------

static char32_t utf8_4b_to_utf32(uint8_t c1, uint8_t c2, uint8_t c3, uint8_t c4) {
    return ((c1 & 0x07) << 18) | ((c2 & 0x3f) << 12) | ((c3 & 0x3f) << 6) | (c4 & 0x3f);
}

// TODO: current behavior of converting UTF8 to UTF-16 has a few issues below
//
// 1. invalid trailing bytes (i.e. not b'10xxxxxx) are treated as valid trailing
//    bytes and follows normal conversion rules
// 2. invalid leading byte (b'10xxxxxx) is treated as a valid single UTF-8 byte
// 3. invalid leading byte (b'11111xxx) is treated as a valid leading byte
//    (same as b'11110xxx) for a 4-byte UTF-8 sequence
// 4. an invalid 4-byte UTF-8 sequence that translates to a codepoint < U+10000
//    will be converted as a valid UTF-16 character
//
// We keep the current behavior as is but with warnings logged, so as not to
// break compatibility.  However, this needs to be addressed later.

ssize_t utf8_to_utf16_length(const uint8_t* u8str, size_t u8len, bool overreadIsFatal)
{
    if (u8str == nullptr)
        return -1;

    const uint8_t* const in_end = u8str + u8len;
    const uint8_t* in = u8str;
    size_t utf16_len = 0;

    while (in < in_end) {
        uint8_t c = *in;
        utf16_len++;
        if (LIKELY((c & 0x80) == 0)) {
            in++;
            continue;
        }
        if (UNLIKELY(c < 0xc0)) {
            ALOGW("Invalid UTF-8 leading byte: 0x%02x", c);
            in++;
            continue;
        }
        if (LIKELY(c < 0xe0)) {
            in += 2;
            continue;
        }
        if (LIKELY(c < 0xf0)) {
            in += 3;
            continue;
        } else {
            uint8_t c2, c3, c4;
            if (UNLIKELY(c >= 0xf8)) {
                ALOGW("Invalid UTF-8 leading byte: 0x%02x", c);
            }
            c2 = in[1]; c3 = in[2]; c4 = in[3];
            if (utf8_4b_to_utf32(c, c2, c3, c4) >= 0x10000) {
                utf16_len++;
            }
            in += 4;
            continue;
        }
    }
    if (in == in_end) {
        return utf16_len < SSIZE_MAX ? utf16_len : -1;
    }
    if (overreadIsFatal)
        LOG_ALWAYS_FATAL("Attempt to overread computing length of utf8 string");
    return -1;
}

char16_t* utf8_to_utf16(const uint8_t* u8str, size_t u8len, char16_t* u16str, size_t u16len) {
    // A value > SSIZE_MAX is probably a negative value returned as an error and casted.
    LOG_ALWAYS_FATAL_IF(u16len == 0 || u16len > SSIZE_MAX, "u16len is %zu", u16len);
    char16_t* end = utf8_to_utf16_no_null_terminator(u8str, u8len, u16str, u16len - 1);
    *end = 0;
    return end;
}

char16_t* utf8_to_utf16_no_null_terminator(
        const uint8_t* src, size_t srcLen, char16_t* dst, size_t dstLen) {
    if (src == nullptr || srcLen == 0 || dstLen == 0) {
        return dst;
    }
    // A value > SSIZE_MAX is probably a negative value returned as an error and casted.
    LOG_ALWAYS_FATAL_IF(dstLen > SSIZE_MAX, "dstLen is %zu", dstLen);

    const uint8_t* const in_end = src + srcLen;
    const uint8_t* in = src;
    const char16_t* const out_end = dst + dstLen;
    char16_t* out = dst;
    uint8_t c, c2, c3, c4;
    char32_t w;

    auto err_in = [&c, &out]() {
        ALOGW("Unended UTF-8 byte: 0x%02x", c);
        return out;
    };

    while (in < in_end && out < out_end) {
        c = *in++;
        if (LIKELY((c & 0x80) == 0)) {
            *out++ = (char16_t)(c);
            continue;
        }
        if (UNLIKELY(c < 0xc0)) {
            ALOGW("Invalid UTF-8 leading byte: 0x%02x", c);
            *out++ = (char16_t)(c);
            continue;
        }
        if (LIKELY(c < 0xe0)) {
            if (UNLIKELY(in + 1 > in_end)) {
                return err_in();
            }
            c2 = *in++;
            *out++ = (char16_t)(((c & 0x1f) << 6) | (c2 & 0x3f));
            continue;
        }
        if (LIKELY(c < 0xf0)) {
            if (UNLIKELY(in + 2 > in_end)) {
                return err_in();
            }
            c2 = *in++; c3 = *in++;
            *out++ = (char16_t)(((c & 0x0f) << 12) |
                                ((c2 & 0x3f) << 6) | (c3 & 0x3f));
            continue;
        } else {
            if (UNLIKELY(in + 3 > in_end)) {
                return err_in();
            }
            if (UNLIKELY(c >= 0xf8)) {
                ALOGW("Invalid UTF-8 leading byte: 0x%02x", c);
            }
            // Multiple UTF16 characters with surrogates
            c2 = *in++; c3 = *in++; c4 = *in++;
            w = utf8_4b_to_utf32(c, c2, c3, c4);
            if (UNLIKELY(w < 0x10000)) {
                *out++ = (char16_t)(w);
            } else {
                if (UNLIKELY(out + 2 > out_end)) {
                    // Ooops.... not enough room for this surrogate pair.
                    return out;
                }
                *out++ = (char16_t)(((w - 0x10000) >> 10) + 0xd800);
                *out++ = (char16_t)(((w - 0x10000) & 0x3ff) + 0xdc00);
            }
            continue;
        }
    }
    return out;
}

}