1 /*
2 * Copyright (C) 2005 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define LOG_TAG "unicode"
18
19 #include <utils/Unicode.h>
20 #include <limits.h>
21
22 #include <log/log.h>
23
24 #if defined(_WIN32)
25 # undef nhtol
26 # undef htonl
27 # undef nhtos
28 # undef htons
29
30 # define ntohl(x) ( ((x) << 24) | (((x) >> 24) & 255) | (((x) << 8) & 0xff0000) | (((x) >> 8) & 0xff00) )
31 # define htonl(x) ntohl(x)
32 # define ntohs(x) ( (((x) << 8) & 0xff00) | (((x) >> 8) & 255) )
33 # define htons(x) ntohs(x)
34 #else
35 # include <netinet/in.h>
36 #endif
37
38 extern "C" {
39
40 static const char32_t kByteMask = 0x000000BF;
41 static const char32_t kByteMark = 0x00000080;
42
43 // Surrogates aren't valid for UTF-32 characters, so define some
44 // constants that will let us screen them out.
45 static const char32_t kUnicodeSurrogateHighStart = 0x0000D800;
46 // Unused, here for completeness:
47 // static const char32_t kUnicodeSurrogateHighEnd = 0x0000DBFF;
48 // static const char32_t kUnicodeSurrogateLowStart = 0x0000DC00;
49 static const char32_t kUnicodeSurrogateLowEnd = 0x0000DFFF;
50 static const char32_t kUnicodeSurrogateStart = kUnicodeSurrogateHighStart;
51 static const char32_t kUnicodeSurrogateEnd = kUnicodeSurrogateLowEnd;
52 static const char32_t kUnicodeMaxCodepoint = 0x0010FFFF;
53
54 // Mask used to set appropriate bits in first byte of UTF-8 sequence,
55 // indexed by number of bytes in the sequence.
56 // 0xxxxxxx
57 // -> (00-7f) 7bit. Bit mask for the first byte is 0x00000000
58 // 110yyyyx 10xxxxxx
59 // -> (c0-df)(80-bf) 11bit. Bit mask is 0x000000C0
60 // 1110yyyy 10yxxxxx 10xxxxxx
61 // -> (e0-ef)(80-bf)(80-bf) 16bit. Bit mask is 0x000000E0
62 // 11110yyy 10yyxxxx 10xxxxxx 10xxxxxx
63 // -> (f0-f7)(80-bf)(80-bf)(80-bf) 21bit. Bit mask is 0x000000F0
64 static const char32_t kFirstByteMark[] = {
65 0x00000000, 0x00000000, 0x000000C0, 0x000000E0, 0x000000F0
66 };
67
68 // --------------------------------------------------------------------------
69 // UTF-32
70 // --------------------------------------------------------------------------
71
72 /**
73 * Return number of UTF-8 bytes required for the character. If the character
74 * is invalid, return size of 0.
75 */
utf32_codepoint_utf8_length(char32_t srcChar)76 static inline size_t utf32_codepoint_utf8_length(char32_t srcChar)
77 {
78 // Figure out how many bytes the result will require.
79 if (srcChar < 0x00000080) {
80 return 1;
81 } else if (srcChar < 0x00000800) {
82 return 2;
83 } else if (srcChar < 0x00010000) {
84 if ((srcChar < kUnicodeSurrogateStart) || (srcChar > kUnicodeSurrogateEnd)) {
85 return 3;
86 } else {
87 // Surrogates are invalid UTF-32 characters.
88 return 0;
89 }
90 }
91 // Max code point for Unicode is 0x0010FFFF.
92 else if (srcChar <= kUnicodeMaxCodepoint) {
93 return 4;
94 } else {
95 // Invalid UTF-32 character.
96 return 0;
97 }
98 }
99
100 // Write out the source character to <dstP>.
101
utf32_codepoint_to_utf8(uint8_t * dstP,char32_t srcChar,size_t bytes)102 static inline void utf32_codepoint_to_utf8(uint8_t* dstP, char32_t srcChar, size_t bytes)
103 {
104 dstP += bytes;
105 switch (bytes)
106 { /* note: everything falls through. */
107 case 4: *--dstP = (uint8_t)((srcChar | kByteMark) & kByteMask); srcChar >>= 6;
108 case 3: *--dstP = (uint8_t)((srcChar | kByteMark) & kByteMask); srcChar >>= 6;
109 case 2: *--dstP = (uint8_t)((srcChar | kByteMark) & kByteMask); srcChar >>= 6;
110 case 1: *--dstP = (uint8_t)(srcChar | kFirstByteMark[bytes]);
111 }
112 }
113
strlen32(const char32_t * s)114 size_t strlen32(const char32_t *s)
115 {
116 const char32_t *ss = s;
117 while ( *ss )
118 ss++;
119 return ss-s;
120 }
121
strnlen32(const char32_t * s,size_t maxlen)122 size_t strnlen32(const char32_t *s, size_t maxlen)
123 {
124 const char32_t *ss = s;
125 while ((maxlen > 0) && *ss) {
126 ss++;
127 maxlen--;
128 }
129 return ss-s;
130 }
131
utf32_at_internal(const char * cur,size_t * num_read)132 static inline int32_t utf32_at_internal(const char* cur, size_t *num_read)
133 {
134 const char first_char = *cur;
135 if ((first_char & 0x80) == 0) { // ASCII
136 *num_read = 1;
137 return *cur;
138 }
139 cur++;
140 char32_t mask, to_ignore_mask;
141 size_t num_to_read = 0;
142 char32_t utf32 = first_char;
143 for (num_to_read = 1, mask = 0x40, to_ignore_mask = 0xFFFFFF80;
144 (first_char & mask);
145 num_to_read++, to_ignore_mask |= mask, mask >>= 1) {
146 // 0x3F == 00111111
147 utf32 = (utf32 << 6) + (*cur++ & 0x3F);
148 }
149 to_ignore_mask |= mask;
150 utf32 &= ~(to_ignore_mask << (6 * (num_to_read - 1)));
151
152 *num_read = num_to_read;
153 return static_cast<int32_t>(utf32);
154 }
155
utf32_from_utf8_at(const char * src,size_t src_len,size_t index,size_t * next_index)156 int32_t utf32_from_utf8_at(const char *src, size_t src_len, size_t index, size_t *next_index)
157 {
158 if (index >= src_len) {
159 return -1;
160 }
161 size_t dummy_index;
162 if (next_index == NULL) {
163 next_index = &dummy_index;
164 }
165 size_t num_read;
166 int32_t ret = utf32_at_internal(src + index, &num_read);
167 if (ret >= 0) {
168 *next_index = index + num_read;
169 }
170
171 return ret;
172 }
173
utf32_to_utf8_length(const char32_t * src,size_t src_len)174 ssize_t utf32_to_utf8_length(const char32_t *src, size_t src_len)
175 {
176 if (src == NULL || src_len == 0) {
177 return -1;
178 }
179
180 size_t ret = 0;
181 const char32_t *end = src + src_len;
182 while (src < end) {
183 size_t char_len = utf32_codepoint_utf8_length(*src++);
184 if (SSIZE_MAX - char_len < ret) {
185 // If this happens, we would overflow the ssize_t type when
186 // returning from this function, so we cannot express how
187 // long this string is in an ssize_t.
188 android_errorWriteLog(0x534e4554, "37723026");
189 return -1;
190 }
191 ret += char_len;
192 }
193 return ret;
194 }
195
utf32_to_utf8(const char32_t * src,size_t src_len,char * dst,size_t dst_len)196 void utf32_to_utf8(const char32_t* src, size_t src_len, char* dst, size_t dst_len)
197 {
198 if (src == NULL || src_len == 0 || dst == NULL) {
199 return;
200 }
201
202 const char32_t *cur_utf32 = src;
203 const char32_t *end_utf32 = src + src_len;
204 char *cur = dst;
205 while (cur_utf32 < end_utf32) {
206 size_t len = utf32_codepoint_utf8_length(*cur_utf32);
207 LOG_ALWAYS_FATAL_IF(dst_len < len, "%zu < %zu", dst_len, len);
208 utf32_codepoint_to_utf8((uint8_t *)cur, *cur_utf32++, len);
209 cur += len;
210 dst_len -= len;
211 }
212 LOG_ALWAYS_FATAL_IF(dst_len < 1, "dst_len < 1: %zu < 1", dst_len);
213 *cur = '\0';
214 }
215
216 // --------------------------------------------------------------------------
217 // UTF-16
218 // --------------------------------------------------------------------------
219
strcmp16(const char16_t * s1,const char16_t * s2)220 int strcmp16(const char16_t *s1, const char16_t *s2)
221 {
222 char16_t ch;
223 int d = 0;
224
225 while ( 1 ) {
226 d = (int)(ch = *s1++) - (int)*s2++;
227 if ( d || !ch )
228 break;
229 }
230
231 return d;
232 }
233
strncmp16(const char16_t * s1,const char16_t * s2,size_t n)234 int strncmp16(const char16_t *s1, const char16_t *s2, size_t n)
235 {
236 char16_t ch;
237 int d = 0;
238
239 if (n == 0) {
240 return 0;
241 }
242
243 do {
244 d = (int)(ch = *s1++) - (int)*s2++;
245 if ( d || !ch ) {
246 break;
247 }
248 } while (--n);
249
250 return d;
251 }
252
strcpy16(char16_t * dst,const char16_t * src)253 char16_t *strcpy16(char16_t *dst, const char16_t *src)
254 {
255 char16_t *q = dst;
256 const char16_t *p = src;
257 char16_t ch;
258
259 do {
260 *q++ = ch = *p++;
261 } while ( ch );
262
263 return dst;
264 }
265
strlen16(const char16_t * s)266 size_t strlen16(const char16_t *s)
267 {
268 const char16_t *ss = s;
269 while ( *ss )
270 ss++;
271 return ss-s;
272 }
273
274
strncpy16(char16_t * dst,const char16_t * src,size_t n)275 char16_t *strncpy16(char16_t *dst, const char16_t *src, size_t n)
276 {
277 char16_t *q = dst;
278 const char16_t *p = src;
279 char ch;
280
281 while (n) {
282 n--;
283 *q++ = ch = *p++;
284 if ( !ch )
285 break;
286 }
287
288 *q = 0;
289
290 return dst;
291 }
292
strnlen16(const char16_t * s,size_t maxlen)293 size_t strnlen16(const char16_t *s, size_t maxlen)
294 {
295 const char16_t *ss = s;
296
297 /* Important: the maxlen test must precede the reference through ss;
298 since the byte beyond the maximum may segfault */
299 while ((maxlen > 0) && *ss) {
300 ss++;
301 maxlen--;
302 }
303 return ss-s;
304 }
305
strstr16(const char16_t * src,const char16_t * target)306 char16_t* strstr16(const char16_t* src, const char16_t* target)
307 {
308 const char16_t needle = *target++;
309 const size_t target_len = strlen16(target);
310 if (needle != '\0') {
311 do {
312 do {
313 if (*src == '\0') {
314 return nullptr;
315 }
316 } while (*src++ != needle);
317 } while (strncmp16(src, target, target_len) != 0);
318 src--;
319 }
320
321 return (char16_t*)src;
322 }
323
324
strzcmp16(const char16_t * s1,size_t n1,const char16_t * s2,size_t n2)325 int strzcmp16(const char16_t *s1, size_t n1, const char16_t *s2, size_t n2)
326 {
327 const char16_t* e1 = s1+n1;
328 const char16_t* e2 = s2+n2;
329
330 while (s1 < e1 && s2 < e2) {
331 const int d = (int)*s1++ - (int)*s2++;
332 if (d) {
333 return d;
334 }
335 }
336
337 return n1 < n2
338 ? (0 - (int)*s2)
339 : (n1 > n2
340 ? ((int)*s1 - 0)
341 : 0);
342 }
343
strzcmp16_h_n(const char16_t * s1H,size_t n1,const char16_t * s2N,size_t n2)344 int strzcmp16_h_n(const char16_t *s1H, size_t n1, const char16_t *s2N, size_t n2)
345 {
346 const char16_t* e1 = s1H+n1;
347 const char16_t* e2 = s2N+n2;
348
349 while (s1H < e1 && s2N < e2) {
350 const char16_t c2 = ntohs(*s2N);
351 const int d = (int)*s1H++ - (int)c2;
352 s2N++;
353 if (d) {
354 return d;
355 }
356 }
357
358 return n1 < n2
359 ? (0 - (int)ntohs(*s2N))
360 : (n1 > n2
361 ? ((int)*s1H - 0)
362 : 0);
363 }
364
utf16_to_utf8(const char16_t * src,size_t src_len,char * dst,size_t dst_len)365 void utf16_to_utf8(const char16_t* src, size_t src_len, char* dst, size_t dst_len)
366 {
367 if (src == NULL || src_len == 0 || dst == NULL) {
368 return;
369 }
370
371 const char16_t* cur_utf16 = src;
372 const char16_t* const end_utf16 = src + src_len;
373 char *cur = dst;
374 while (cur_utf16 < end_utf16) {
375 char32_t utf32;
376 // surrogate pairs
377 if((*cur_utf16 & 0xFC00) == 0xD800 && (cur_utf16 + 1) < end_utf16
378 && (*(cur_utf16 + 1) & 0xFC00) == 0xDC00) {
379 utf32 = (*cur_utf16++ - 0xD800) << 10;
380 utf32 |= *cur_utf16++ - 0xDC00;
381 utf32 += 0x10000;
382 } else {
383 utf32 = (char32_t) *cur_utf16++;
384 }
385 const size_t len = utf32_codepoint_utf8_length(utf32);
386 LOG_ALWAYS_FATAL_IF(dst_len < len, "%zu < %zu", dst_len, len);
387 utf32_codepoint_to_utf8((uint8_t*)cur, utf32, len);
388 cur += len;
389 dst_len -= len;
390 }
391 LOG_ALWAYS_FATAL_IF(dst_len < 1, "%zu < 1", dst_len);
392 *cur = '\0';
393 }
394
395 // --------------------------------------------------------------------------
396 // UTF-8
397 // --------------------------------------------------------------------------
398
utf8_length(const char * src)399 ssize_t utf8_length(const char *src)
400 {
401 const char *cur = src;
402 size_t ret = 0;
403 while (*cur != '\0') {
404 const char first_char = *cur++;
405 if ((first_char & 0x80) == 0) { // ASCII
406 ret += 1;
407 continue;
408 }
409 // (UTF-8's character must not be like 10xxxxxx,
410 // but 110xxxxx, 1110xxxx, ... or 1111110x)
411 if ((first_char & 0x40) == 0) {
412 return -1;
413 }
414
415 int32_t mask, to_ignore_mask;
416 size_t num_to_read = 0;
417 char32_t utf32 = 0;
418 for (num_to_read = 1, mask = 0x40, to_ignore_mask = 0x80;
419 num_to_read < 5 && (first_char & mask);
420 num_to_read++, to_ignore_mask |= mask, mask >>= 1) {
421 if ((*cur & 0xC0) != 0x80) { // must be 10xxxxxx
422 return -1;
423 }
424 // 0x3F == 00111111
425 utf32 = (utf32 << 6) + (*cur++ & 0x3F);
426 }
427 // "first_char" must be (110xxxxx - 11110xxx)
428 if (num_to_read == 5) {
429 return -1;
430 }
431 to_ignore_mask |= mask;
432 utf32 |= ((~to_ignore_mask) & first_char) << (6 * (num_to_read - 1));
433 if (utf32 > kUnicodeMaxCodepoint) {
434 return -1;
435 }
436
437 ret += num_to_read;
438 }
439 return ret;
440 }
441
utf16_to_utf8_length(const char16_t * src,size_t src_len)442 ssize_t utf16_to_utf8_length(const char16_t *src, size_t src_len)
443 {
444 if (src == NULL || src_len == 0) {
445 return -1;
446 }
447
448 size_t ret = 0;
449 const char16_t* const end = src + src_len;
450 while (src < end) {
451 size_t char_len;
452 if ((*src & 0xFC00) == 0xD800 && (src + 1) < end
453 && (*(src + 1) & 0xFC00) == 0xDC00) {
454 // surrogate pairs are always 4 bytes.
455 char_len = 4;
456 src += 2;
457 } else {
458 char_len = utf32_codepoint_utf8_length((char32_t)*src++);
459 }
460 if (SSIZE_MAX - char_len < ret) {
461 // If this happens, we would overflow the ssize_t type when
462 // returning from this function, so we cannot express how
463 // long this string is in an ssize_t.
464 android_errorWriteLog(0x534e4554, "37723026");
465 return -1;
466 }
467 ret += char_len;
468 }
469 return ret;
470 }
471
472 /**
473 * Returns 1-4 based on the number of leading bits.
474 *
475 * 1111 -> 4
476 * 1110 -> 3
477 * 110x -> 2
478 * 10xx -> 1
479 * 0xxx -> 1
480 */
utf8_codepoint_len(uint8_t ch)481 static inline size_t utf8_codepoint_len(uint8_t ch)
482 {
483 return ((0xe5000000 >> ((ch >> 3) & 0x1e)) & 3) + 1;
484 }
485
utf8_shift_and_mask(uint32_t * codePoint,const uint8_t byte)486 static inline void utf8_shift_and_mask(uint32_t* codePoint, const uint8_t byte)
487 {
488 *codePoint <<= 6;
489 *codePoint |= 0x3F & byte;
490 }
491
utf8_to_utf32_length(const char * src,size_t src_len)492 size_t utf8_to_utf32_length(const char *src, size_t src_len)
493 {
494 if (src == NULL || src_len == 0) {
495 return 0;
496 }
497 size_t ret = 0;
498 const char* cur;
499 const char* end;
500 size_t num_to_skip;
501 for (cur = src, end = src + src_len, num_to_skip = 1;
502 cur < end;
503 cur += num_to_skip, ret++) {
504 const char first_char = *cur;
505 num_to_skip = 1;
506 if ((first_char & 0x80) == 0) { // ASCII
507 continue;
508 }
509 int32_t mask;
510
511 for (mask = 0x40; (first_char & mask); num_to_skip++, mask >>= 1) {
512 }
513 }
514 return ret;
515 }
516
utf8_to_utf32(const char * src,size_t src_len,char32_t * dst)517 void utf8_to_utf32(const char* src, size_t src_len, char32_t* dst)
518 {
519 if (src == NULL || src_len == 0 || dst == NULL) {
520 return;
521 }
522
523 const char* cur = src;
524 const char* const end = src + src_len;
525 char32_t* cur_utf32 = dst;
526 while (cur < end) {
527 size_t num_read;
528 *cur_utf32++ = static_cast<char32_t>(utf32_at_internal(cur, &num_read));
529 cur += num_read;
530 }
531 *cur_utf32 = 0;
532 }
533
utf8_to_utf32_codepoint(const uint8_t * src,size_t length)534 static inline uint32_t utf8_to_utf32_codepoint(const uint8_t *src, size_t length)
535 {
536 uint32_t unicode;
537
538 switch (length)
539 {
540 case 1:
541 return src[0];
542 case 2:
543 unicode = src[0] & 0x1f;
544 utf8_shift_and_mask(&unicode, src[1]);
545 return unicode;
546 case 3:
547 unicode = src[0] & 0x0f;
548 utf8_shift_and_mask(&unicode, src[1]);
549 utf8_shift_and_mask(&unicode, src[2]);
550 return unicode;
551 case 4:
552 unicode = src[0] & 0x07;
553 utf8_shift_and_mask(&unicode, src[1]);
554 utf8_shift_and_mask(&unicode, src[2]);
555 utf8_shift_and_mask(&unicode, src[3]);
556 return unicode;
557 default:
558 return 0xffff;
559 }
560
561 //printf("Char at %p: len=%d, utf-16=%p\n", src, length, (void*)result);
562 }
563
utf8_to_utf16_length(const uint8_t * u8str,size_t u8len,bool overreadIsFatal)564 ssize_t utf8_to_utf16_length(const uint8_t* u8str, size_t u8len, bool overreadIsFatal)
565 {
566 const uint8_t* const u8end = u8str + u8len;
567 const uint8_t* u8cur = u8str;
568
569 /* Validate that the UTF-8 is the correct len */
570 size_t u16measuredLen = 0;
571 while (u8cur < u8end) {
572 u16measuredLen++;
573 int u8charLen = utf8_codepoint_len(*u8cur);
574 // Malformed utf8, some characters are beyond the end.
575 // Cases:
576 // If u8charLen == 1, this becomes u8cur >= u8end, which cannot happen as u8cur < u8end,
577 // then this condition fail and we continue, as expected.
578 // If u8charLen == 2, this becomes u8cur + 1 >= u8end, which fails only if
579 // u8cur == u8end - 1, that is, there was only one remaining character to read but we need
580 // 2 of them. This condition holds and we return -1, as expected.
581 if (u8cur + u8charLen - 1 >= u8end) {
582 if (overreadIsFatal) {
583 LOG_ALWAYS_FATAL("Attempt to overread computing length of utf8 string");
584 } else {
585 return -1;
586 }
587 }
588 uint32_t codepoint = utf8_to_utf32_codepoint(u8cur, u8charLen);
589 if (codepoint > 0xFFFF) u16measuredLen++; // this will be a surrogate pair in utf16
590 u8cur += u8charLen;
591 }
592
593 /**
594 * Make sure that we ended where we thought we would and the output UTF-16
595 * will be exactly how long we were told it would be.
596 */
597 if (u8cur != u8end) {
598 return -1;
599 }
600
601 return u16measuredLen;
602 }
603
utf8_to_utf16(const uint8_t * u8str,size_t u8len,char16_t * u16str,size_t u16len)604 char16_t* utf8_to_utf16(const uint8_t* u8str, size_t u8len, char16_t* u16str, size_t u16len) {
605 // A value > SSIZE_MAX is probably a negative value returned as an error and casted.
606 LOG_ALWAYS_FATAL_IF(u16len == 0 || u16len > SSIZE_MAX, "u16len is %zu", u16len);
607 char16_t* end = utf8_to_utf16_no_null_terminator(u8str, u8len, u16str, u16len - 1);
608 *end = 0;
609 return end;
610 }
611
utf8_to_utf16_no_null_terminator(const uint8_t * src,size_t srcLen,char16_t * dst,size_t dstLen)612 char16_t* utf8_to_utf16_no_null_terminator(
613 const uint8_t* src, size_t srcLen, char16_t* dst, size_t dstLen) {
614 if (dstLen == 0) {
615 return dst;
616 }
617 // A value > SSIZE_MAX is probably a negative value returned as an error and casted.
618 LOG_ALWAYS_FATAL_IF(dstLen > SSIZE_MAX, "dstLen is %zu", dstLen);
619 const uint8_t* const u8end = src + srcLen;
620 const uint8_t* u8cur = src;
621 const char16_t* const u16end = dst + dstLen;
622 char16_t* u16cur = dst;
623
624 while (u8cur < u8end && u16cur < u16end) {
625 size_t u8len = utf8_codepoint_len(*u8cur);
626 uint32_t codepoint = utf8_to_utf32_codepoint(u8cur, u8len);
627
628 // Convert the UTF32 codepoint to one or more UTF16 codepoints
629 if (codepoint <= 0xFFFF) {
630 // Single UTF16 character
631 *u16cur++ = (char16_t) codepoint;
632 } else {
633 // Multiple UTF16 characters with surrogates
634 codepoint = codepoint - 0x10000;
635 *u16cur++ = (char16_t) ((codepoint >> 10) + 0xD800);
636 if (u16cur >= u16end) {
637 // Ooops... not enough room for this surrogate pair.
638 return u16cur-1;
639 }
640 *u16cur++ = (char16_t) ((codepoint & 0x3FF) + 0xDC00);
641 }
642
643 u8cur += u8len;
644 }
645 return u16cur;
646 }
647
648 }
649