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/thirdparty/breakpad/common/convert_UTF.c

http://github.com/tomahawk-player/tomahawk
C | 533 lines | 359 code | 36 blank | 138 comment | 122 complexity | 4d044a3fc0cf0a802ea0a9b7997bbf2c MD5 | raw file
  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
 25Conversions between UTF32, UTF-16, and UTF-8. Source code file.
 26Author: Mark E. Davis, 1994.
 27Rev History: Rick McGowan, fixes & updates May 2001.
 28Sept 2001: fixed const & error conditions per
 29mods suggested by S. Parent & A. Lillich.
 30June 2002: Tim Dodd added detection and handling of incomplete
 31source sequences, enhanced error detection, added casts
 32to eliminate compiler warnings.
 33July 2003: slight mods to back out aggressive FFFE detection.
 34Jan 2004: updated switches in from-UTF8 conversions.
 35Oct 2004: updated to use UNI_MAX_LEGAL_UTF32 in UTF-32 conversions.
 36
 37See 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
 47static const int halfShift  = 10; /* used for shifting by 10 bits */
 48
 49static const UTF32 halfBase = 0x0010000UL;
 50static 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
 61ConversionResult 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;
104return result;
105}
106
107/* --------------------------------------------------------------------- */
108
109ConversionResult 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 */
172static 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 */
188static 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 */
198static 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
212ConversionResult 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;
276return 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
292static 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 */
323Boolean 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
333ConversionResult 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;
400return result;
401}
402
403/* --------------------------------------------------------------------- */
404
405ConversionResult 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;
452return result;
453}
454
455/* --------------------------------------------------------------------- */
456
457ConversionResult 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
518Note A.
519The fall-through switches in UTF-8 reading code save a
520temp variable, some decrements & conditionals.  The switches
521are 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}
530In UTF-8 writing code, the switches on "bytesToWrite" are
531similarly unrolled loops.
532
533--------------------------------------------------------------------- */