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comparison: toolkit/crashreporter/google-breakpad/src/common/convert_UTF.c

toolkit/crashreporter/google-breakpad/src/common/convert_UTF.c

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1 /*
2 * Copyright 2001-2004 Unicode, Inc.
3 *
4 * Disclaimer
5 *
6 * This source code is provided as is by Unicode, Inc. No claims are
7 * made as to fitness for any particular purpose. No warranties of any
8 * kind are expressed or implied. The recipient agrees to determine
9 * applicability of information provided. If this file has been
10 * purchased on magnetic or optical media from Unicode, Inc., the
11 * sole remedy for any claim will be exchange of defective media
12 * within 90 days of receipt.
13 *
14 * Limitations on Rights to Redistribute This Code
15 *
16 * Unicode, Inc. hereby grants the right to freely use the information
17 * supplied in this file in the creation of products supporting the
18 * Unicode Standard, and to make copies of this file in any form
19 * for internal or external distribution as long as this notice
20 * remains attached.
21 */
22
23 /* ---------------------------------------------------------------------
24
25 Conversions between UTF32, UTF-16, and UTF-8. Source code file.
26 Author: Mark E. Davis, 1994.
27 Rev History: Rick McGowan, fixes & updates May 2001.
28 Sept 2001: fixed const & error conditions per
29 mods suggested by S. Parent & A. Lillich.
30 June 2002: Tim Dodd added detection and handling of incomplete
31 source sequences, enhanced error detection, added casts
32 to eliminate compiler warnings.
33 July 2003: slight mods to back out aggressive FFFE detection.
34 Jan 2004: updated switches in from-UTF8 conversions.
35 Oct 2004: updated to use UNI_MAX_LEGAL_UTF32 in UTF-32 conversions.
36
37 See the header file "ConvertUTF.h" for complete documentation.
38
39 ------------------------------------------------------------------------ */
40
41
42 #include "convert_UTF.h"
43 #ifdef CVTUTF_DEBUG
44 #include <stdio.h>
45 #endif
46
47 static const int halfShift = 10; /* used for shifting by 10 bits */
48
49 static const UTF32 halfBase = 0x0010000UL;
50 static const UTF32 halfMask = 0x3FFUL;
51
52 #define UNI_SUR_HIGH_START (UTF32)0xD800
53 #define UNI_SUR_HIGH_END (UTF32)0xDBFF
54 #define UNI_SUR_LOW_START (UTF32)0xDC00
55 #define UNI_SUR_LOW_END (UTF32)0xDFFF
56 #define false 0
57 #define true 1
58
59 /* --------------------------------------------------------------------- */
60
61 ConversionResult ConvertUTF32toUTF16 (const UTF32** sourceStart, const UTF32* sourceEnd,
62 UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
63 ConversionResult result = conversionOK;
64 const UTF32* source = *sourceStart;
65 UTF16* target = *targetStart;
66 while (source < sourceEnd) {
67 UTF32 ch;
68 if (target >= targetEnd) {
69 result = targetExhausted; break;
70 }
71 ch = *source++;
72 if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
73 /* UTF-16 surrogate values are illegal in UTF-32; 0xffff or 0xfffe are both reserved values */
74 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
75 if (flags == strictConversion) {
76 --source; /* return to the illegal value itself */
77 result = sourceIllegal;
78 break;
79 } else {
80 *target++ = UNI_REPLACEMENT_CHAR;
81 }
82 } else {
83 *target++ = (UTF16)ch; /* normal case */
84 }
85 } else if (ch > UNI_MAX_LEGAL_UTF32) {
86 if (flags == strictConversion) {
87 result = sourceIllegal;
88 } else {
89 *target++ = UNI_REPLACEMENT_CHAR;
90 }
91 } else {
92 /* target is a character in range 0xFFFF - 0x10FFFF. */
93 if (target + 1 >= targetEnd) {
94 --source; /* Back up source pointer! */
95 result = targetExhausted; break;
96 }
97 ch -= halfBase;
98 *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
99 *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
100 }
101 }
102 *sourceStart = source;
103 *targetStart = target;
104 return result;
105 }
106
107 /* --------------------------------------------------------------------- */
108
109 ConversionResult ConvertUTF16toUTF32 (const UTF16** sourceStart, const UTF16* sourceEnd,
110 UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
111 ConversionResult result = conversionOK;
112 const UTF16* source = *sourceStart;
113 UTF32* target = *targetStart;
114 UTF32 ch, ch2;
115 while (source < sourceEnd) {
116 const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
117 ch = *source++;
118 /* If we have a surrogate pair, convert to UTF32 first. */
119 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) {
120 /* If the 16 bits following the high surrogate are in the source buffer... */
121 if (source < sourceEnd) {
122 ch2 = *source;
123 /* If it's a low surrogate, convert to UTF32. */
124 if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
125 ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
126 + (ch2 - UNI_SUR_LOW_START) + halfBase;
127 ++source;
128 } else if (flags == strictConversion) { /* it's an unpaired high surrogate */
129 --source; /* return to the illegal value itself */
130 result = sourceIllegal;
131 break;
132 }
133 } else { /* We don't have the 16 bits following the high surrogate. */
134 --source; /* return to the high surrogate */
135 result = sourceExhausted;
136 break;
137 }
138 } else if (flags == strictConversion) {
139 /* UTF-16 surrogate values are illegal in UTF-32 */
140 if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
141 --source; /* return to the illegal value itself */
142 result = sourceIllegal;
143 break;
144 }
145 }
146 if (target >= targetEnd) {
147 source = oldSource; /* Back up source pointer! */
148 result = targetExhausted; break;
149 }
150 *target++ = ch;
151 }
152 *sourceStart = source;
153 *targetStart = target;
154 #ifdef CVTUTF_DEBUG
155 if (result == sourceIllegal) {
156 fprintf(stderr, "ConvertUTF16toUTF32 illegal seq 0x%04x,%04x\n", ch, ch2);
157 fflush(stderr);
158 }
159 #endif
160 return result;
161 }
162
163 /* --------------------------------------------------------------------- */
164
165 /*
166 * Index into the table below with the first byte of a UTF-8 sequence to
167 * get the number of trailing bytes that are supposed to follow it.
168 * Note that *legal* UTF-8 values can't have 4 or 5-bytes. The table is
169 * left as-is for anyone who may want to do such conversion, which was
170 * allowed in earlier algorithms.
171 */
172 static const char trailingBytesForUTF8[256] = {
173 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
174 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
175 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
176 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
177 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
178 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
179 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
180 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5
181 };
182
183 /*
184 * Magic values subtracted from a buffer value during UTF8 conversion.
185 * This table contains as many values as there might be trailing bytes
186 * in a UTF-8 sequence.
187 */
188 static const UTF32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL,
189 0x03C82080UL, 0xFA082080UL, 0x82082080UL };
190
191 /*
192 * Once the bits are split out into bytes of UTF-8, this is a mask OR-ed
193 * into the first byte, depending on how many bytes follow. There are
194 * as many entries in this table as there are UTF-8 sequence types.
195 * (I.e., one byte sequence, two byte... etc.). Remember that sequencs
196 * for *legal* UTF-8 will be 4 or fewer bytes total.
197 */
198 static const UTF8 firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
199
200 /* --------------------------------------------------------------------- */
201
202 /* The interface converts a whole buffer to avoid function-call overhead.
203 * Constants have been gathered. Loops & conditionals have been removed as
204 * much as possible for efficiency, in favor of drop-through switches.
205 * (See "Note A" at the bottom of the file for equivalent code.)
206 * If your compiler supports it, the "isLegalUTF8" call can be turned
207 * into an inline function.
208 */
209
210 /* --------------------------------------------------------------------- */
211
212 ConversionResult ConvertUTF16toUTF8 (const UTF16** sourceStart, const UTF16* sourceEnd,
213 UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
214 ConversionResult result = conversionOK;
215 const UTF16* source = *sourceStart;
216 UTF8* target = *targetStart;
217 while (source < sourceEnd) {
218 UTF32 ch;
219 unsigned short bytesToWrite = 0;
220 const UTF32 byteMask = 0xBF;
221 const UTF32 byteMark = 0x80;
222 const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
223 ch = *source++;
224 /* If we have a surrogate pair, convert to UTF32 first. */
225 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) {
226 /* If the 16 bits following the high surrogate are in the source buffer... */
227 if (source < sourceEnd) {
228 UTF32 ch2 = *source;
229 /* If it's a low surrogate, convert to UTF32. */
230 if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
231 ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
232 + (ch2 - UNI_SUR_LOW_START) + halfBase;
233 ++source;
234 } else if (flags == strictConversion) { /* it's an unpaired high surrogate */
235 --source; /* return to the illegal value itself */
236 result = sourceIllegal;
237 break;
238 }
239 } else { /* We don't have the 16 bits following the high surrogate. */
240 --source; /* return to the high surrogate */
241 result = sourceExhausted;
242 break;
243 }
244 } else if (flags == strictConversion) {
245 /* UTF-16 surrogate values are illegal in UTF-32 */
246 if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
247 --source; /* return to the illegal value itself */
248 result = sourceIllegal;
249 break;
250 }
251 }
252 /* Figure out how many bytes the result will require */
253 if (ch < (UTF32)0x80) { bytesToWrite = 1;
254 } else if (ch < (UTF32)0x800) { bytesToWrite = 2;
255 } else if (ch < (UTF32)0x10000) { bytesToWrite = 3;
256 } else if (ch < (UTF32)0x110000) { bytesToWrite = 4;
257 } else { bytesToWrite = 3;
258 ch = UNI_REPLACEMENT_CHAR;
259 }
260
261 target += bytesToWrite;
262 if (target > targetEnd) {
263 source = oldSource; /* Back up source pointer! */
264 target -= bytesToWrite; result = targetExhausted; break;
265 }
266 switch (bytesToWrite) { /* note: everything falls through. */
267 case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
268 case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
269 case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
270 case 1: *--target = (UTF8)(ch | firstByteMark[bytesToWrite]);
271 }
272 target += bytesToWrite;
273 }
274 *sourceStart = source;
275 *targetStart = target;
276 return result;
277 }
278
279 /* --------------------------------------------------------------------- */
280
281 /*
282 * Utility routine to tell whether a sequence of bytes is legal UTF-8.
283 * This must be called with the length pre-determined by the first byte.
284 * If not calling this from ConvertUTF8to*, then the length can be set by:
285 * length = trailingBytesForUTF8[*source]+1;
286 * and the sequence is illegal right away if there aren't that many bytes
287 * available.
288 * If presented with a length > 4, this returns false. The Unicode
289 * definition of UTF-8 goes up to 4-byte sequences.
290 */
291
292 static Boolean isLegalUTF8(const UTF8 *source, int length) {
293 UTF8 a;
294 const UTF8 *srcptr = source+length;
295 switch (length) {
296 default: return false;
297 /* Everything else falls through when "true"... */
298 case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
299 case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
300 case 2: if ((a = (*--srcptr)) > 0xBF) return false;
301
302 switch (*source) {
303 /* no fall-through in this inner switch */
304 case 0xE0: if (a < 0xA0) return false; break;
305 case 0xED: if (a > 0x9F) return false; break;
306 case 0xF0: if (a < 0x90) return false; break;
307 case 0xF4: if (a > 0x8F) return false; break;
308 default: if (a < 0x80) return false;
309 }
310
311 case 1: if (*source >= 0x80 && *source < 0xC2) return false;
312 }
313 if (*source > 0xF4) return false;
314 return true;
315 }
316
317 /* --------------------------------------------------------------------- */
318
319 /*
320 * Exported function to return whether a UTF-8 sequence is legal or not.
321 * This is not used here; it's just exported.
322 */
323 Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd) {
324 int length = trailingBytesForUTF8[*source]+1;
325 if (source+length > sourceEnd) {
326 return false;
327 }
328 return isLegalUTF8(source, length);
329 }
330
331 /* --------------------------------------------------------------------- */
332
333 ConversionResult ConvertUTF8toUTF16 (const UTF8** sourceStart, const UTF8* sourceEnd,
334 UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
335 ConversionResult result = conversionOK;
336 const UTF8* source = *sourceStart;
337 UTF16* target = *targetStart;
338 while (source < sourceEnd) {
339 UTF32 ch = 0;
340 unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
341 if (source + extraBytesToRead >= sourceEnd) {
342 result = sourceExhausted; break;
343 }
344 /* Do this check whether lenient or strict */
345 if (! isLegalUTF8(source, extraBytesToRead+1)) {
346 result = sourceIllegal;
347 break;
348 }
349 /*
350 * The cases all fall through. See "Note A" below.
351 */
352 switch (extraBytesToRead) {
353 case 5: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
354 case 4: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
355 case 3: ch += *source++; ch <<= 6;
356 case 2: ch += *source++; ch <<= 6;
357 case 1: ch += *source++; ch <<= 6;
358 case 0: ch += *source++;
359 }
360 ch -= offsetsFromUTF8[extraBytesToRead];
361
362 if (target >= targetEnd) {
363 source -= (extraBytesToRead+1); /* Back up source pointer! */
364 result = targetExhausted; break;
365 }
366 if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
367 /* UTF-16 surrogate values are illegal in UTF-32 */
368 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
369 if (flags == strictConversion) {
370 source -= (extraBytesToRead+1); /* return to the illegal value itself */
371 result = sourceIllegal;
372 break;
373 } else {
374 *target++ = UNI_REPLACEMENT_CHAR;
375 }
376 } else {
377 *target++ = (UTF16)ch; /* normal case */
378 }
379 } else if (ch > UNI_MAX_UTF16) {
380 if (flags == strictConversion) {
381 result = sourceIllegal;
382 source -= (extraBytesToRead+1); /* return to the start */
383 break; /* Bail out; shouldn't continue */
384 } else {
385 *target++ = UNI_REPLACEMENT_CHAR;
386 }
387 } else {
388 /* target is a character in range 0xFFFF - 0x10FFFF. */
389 if (target + 1 >= targetEnd) {
390 source -= (extraBytesToRead+1); /* Back up source pointer! */
391 result = targetExhausted; break;
392 }
393 ch -= halfBase;
394 *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
395 *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
396 }
397 }
398 *sourceStart = source;
399 *targetStart = target;
400 return result;
401 }
402
403 /* --------------------------------------------------------------------- */
404
405 ConversionResult ConvertUTF32toUTF8 (const UTF32** sourceStart, const UTF32* sourceEnd,
406 UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
407 ConversionResult result = conversionOK;
408 const UTF32* source = *sourceStart;
409 UTF8* target = *targetStart;
410 while (source < sourceEnd) {
411 UTF32 ch;
412 unsigned short bytesToWrite = 0;
413 const UTF32 byteMask = 0xBF;
414 const UTF32 byteMark = 0x80;
415 ch = *source++;
416 if (flags == strictConversion ) {
417 /* UTF-16 surrogate values are illegal in UTF-32 */
418 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
419 --source; /* return to the illegal value itself */
420 result = sourceIllegal;
421 break;
422 }
423 }
424 /*
425 * Figure out how many bytes the result will require. Turn any
426 * illegally large UTF32 things (> Plane 17) into replacement chars.
427 */
428 if (ch < (UTF32)0x80) { bytesToWrite = 1;
429 } else if (ch < (UTF32)0x800) { bytesToWrite = 2;
430 } else if (ch < (UTF32)0x10000) { bytesToWrite = 3;
431 } else if (ch <= UNI_MAX_LEGAL_UTF32) { bytesToWrite = 4;
432 } else { bytesToWrite = 3;
433 ch = UNI_REPLACEMENT_CHAR;
434 result = sourceIllegal;
435 }
436
437 target += bytesToWrite;
438 if (target > targetEnd) {
439 --source; /* Back up source pointer! */
440 target -= bytesToWrite; result = targetExhausted; break;
441 }
442 switch (bytesToWrite) { /* note: everything falls through. */
443 case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
444 case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
445 case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
446 case 1: *--target = (UTF8) (ch | firstByteMark[bytesToWrite]);
447 }
448 target += bytesToWrite;
449 }
450 *sourceStart = source;
451 *targetStart = target;
452 return result;
453 }
454
455 /* --------------------------------------------------------------------- */
456
457 ConversionResult ConvertUTF8toUTF32 (const UTF8** sourceStart, const UTF8* sourceEnd,
458 UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
459 ConversionResult result = conversionOK;
460 const UTF8* source = *sourceStart;
461 UTF32* target = *targetStart;
462 while (source < sourceEnd) {
463 UTF32 ch = 0;
464 unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
465 if (source + extraBytesToRead >= sourceEnd) {
466 result = sourceExhausted; break;
467 }
468 /* Do this check whether lenient or strict */
469 if (! isLegalUTF8(source, extraBytesToRead+1)) {
470 result = sourceIllegal;
471 break;
472 }
473 /*
474 * The cases all fall through. See "Note A" below.
475 */
476 switch (extraBytesToRead) {
477 case 5: ch += *source++; ch <<= 6;
478 case 4: ch += *source++; ch <<= 6;
479 case 3: ch += *source++; ch <<= 6;
480 case 2: ch += *source++; ch <<= 6;
481 case 1: ch += *source++; ch <<= 6;
482 case 0: ch += *source++;
483 }
484 ch -= offsetsFromUTF8[extraBytesToRead];
485
486 if (target >= targetEnd) {
487 source -= (extraBytesToRead+1); /* Back up the source pointer! */
488 result = targetExhausted; break;
489 }
490 if (ch <= UNI_MAX_LEGAL_UTF32) {
491 /*
492 * UTF-16 surrogate values are illegal in UTF-32, and anything
493 * over Plane 17 (> 0x10FFFF) is illegal.
494 */
495 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
496 if (flags == strictConversion) {
497 source -= (extraBytesToRead+1); /* return to the illegal value itself */
498 result = sourceIllegal;
499 break;
500 } else {
501 *target++ = UNI_REPLACEMENT_CHAR;
502 }
503 } else {
504 *target++ = ch;
505 }
506 } else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */
507 result = sourceIllegal;
508 *target++ = UNI_REPLACEMENT_CHAR;
509 }
510 }
511 *sourceStart = source;
512 *targetStart = target;
513 return result;
514 }
515
516 /* ---------------------------------------------------------------------
517
518 Note A.
519 The fall-through switches in UTF-8 reading code save a
520 temp variable, some decrements & conditionals. The switches
521 are equivalent to the following loop:
522 {
523 int tmpBytesToRead = extraBytesToRead+1;
524 do {
525 ch += *source++;
526 --tmpBytesToRead;
527 if (tmpBytesToRead) ch <<= 6;
528 } while (tmpBytesToRead > 0);
529 }
530 In UTF-8 writing code, the switches on "bytesToWrite" are
531 similarly unrolled loops.
532
533 --------------------------------------------------------------------- */

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