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 0 : ConversionResult ConvertUTF32toUTF16 (const UTF32** sourceStart, const UTF32* sourceEnd,
62 : UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
63 0 : ConversionResult result = conversionOK;
64 0 : const UTF32* source = *sourceStart;
65 0 : UTF16* target = *targetStart;
66 0 : while (source < sourceEnd) {
67 : UTF32 ch;
68 0 : if (target >= targetEnd) {
69 0 : result = targetExhausted; break;
70 : }
71 0 : ch = *source++;
72 0 : 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 0 : if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
75 0 : if (flags == strictConversion) {
76 0 : --source; /* return to the illegal value itself */
77 0 : result = sourceIllegal;
78 0 : break;
79 : } else {
80 0 : *target++ = UNI_REPLACEMENT_CHAR;
81 : }
82 : } else {
83 0 : *target++ = (UTF16)ch; /* normal case */
84 : }
85 0 : } else if (ch > UNI_MAX_LEGAL_UTF32) {
86 0 : if (flags == strictConversion) {
87 0 : result = sourceIllegal;
88 : } else {
89 0 : *target++ = UNI_REPLACEMENT_CHAR;
90 : }
91 : } else {
92 : /* target is a character in range 0xFFFF - 0x10FFFF. */
93 0 : if (target + 1 >= targetEnd) {
94 0 : --source; /* Back up source pointer! */
95 0 : result = targetExhausted; break;
96 : }
97 0 : ch -= halfBase;
98 0 : *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
99 0 : *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
100 : }
101 : }
102 0 : *sourceStart = source;
103 0 : *targetStart = target;
104 0 : return result;
105 : }
106 :
107 : /* --------------------------------------------------------------------- */
108 :
109 0 : ConversionResult ConvertUTF16toUTF32 (const UTF16** sourceStart, const UTF16* sourceEnd,
110 : UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
111 0 : ConversionResult result = conversionOK;
112 0 : const UTF16* source = *sourceStart;
113 0 : UTF32* target = *targetStart;
114 : UTF32 ch, ch2;
115 0 : while (source < sourceEnd) {
116 0 : const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
117 0 : ch = *source++;
118 : /* If we have a surrogate pair, convert to UTF32 first. */
119 0 : 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 0 : if (source < sourceEnd) {
122 0 : ch2 = *source;
123 : /* If it's a low surrogate, convert to UTF32. */
124 0 : if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
125 0 : ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
126 0 : + (ch2 - UNI_SUR_LOW_START) + halfBase;
127 0 : ++source;
128 0 : } else if (flags == strictConversion) { /* it's an unpaired high surrogate */
129 0 : --source; /* return to the illegal value itself */
130 0 : result = sourceIllegal;
131 0 : break;
132 : }
133 : } else { /* We don't have the 16 bits following the high surrogate. */
134 0 : --source; /* return to the high surrogate */
135 0 : result = sourceExhausted;
136 0 : break;
137 : }
138 0 : } else if (flags == strictConversion) {
139 : /* UTF-16 surrogate values are illegal in UTF-32 */
140 0 : if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
141 0 : --source; /* return to the illegal value itself */
142 0 : result = sourceIllegal;
143 0 : break;
144 : }
145 : }
146 0 : if (target >= targetEnd) {
147 0 : source = oldSource; /* Back up source pointer! */
148 0 : result = targetExhausted; break;
149 : }
150 0 : *target++ = ch;
151 : }
152 0 : *sourceStart = source;
153 0 : *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 0 : 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 0 : ConversionResult ConvertUTF16toUTF8 (const UTF16** sourceStart, const UTF16* sourceEnd,
213 : UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
214 0 : ConversionResult result = conversionOK;
215 0 : const UTF16* source = *sourceStart;
216 0 : UTF8* target = *targetStart;
217 0 : while (source < sourceEnd) {
218 : UTF32 ch;
219 0 : unsigned short bytesToWrite = 0;
220 0 : const UTF32 byteMask = 0xBF;
221 0 : const UTF32 byteMark = 0x80;
222 0 : const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
223 0 : ch = *source++;
224 : /* If we have a surrogate pair, convert to UTF32 first. */
225 0 : 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 0 : if (source < sourceEnd) {
228 0 : UTF32 ch2 = *source;
229 : /* If it's a low surrogate, convert to UTF32. */
230 0 : if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
231 0 : ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
232 0 : + (ch2 - UNI_SUR_LOW_START) + halfBase;
233 0 : ++source;
234 0 : } else if (flags == strictConversion) { /* it's an unpaired high surrogate */
235 0 : --source; /* return to the illegal value itself */
236 0 : result = sourceIllegal;
237 0 : break;
238 : }
239 : } else { /* We don't have the 16 bits following the high surrogate. */
240 0 : --source; /* return to the high surrogate */
241 0 : result = sourceExhausted;
242 0 : break;
243 : }
244 0 : } else if (flags == strictConversion) {
245 : /* UTF-16 surrogate values are illegal in UTF-32 */
246 0 : if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
247 0 : --source; /* return to the illegal value itself */
248 0 : result = sourceIllegal;
249 0 : break;
250 : }
251 : }
252 : /* Figure out how many bytes the result will require */
253 0 : if (ch < (UTF32)0x80) { bytesToWrite = 1;
254 0 : } else if (ch < (UTF32)0x800) { bytesToWrite = 2;
255 0 : } else if (ch < (UTF32)0x10000) { bytesToWrite = 3;
256 0 : } else if (ch < (UTF32)0x110000) { bytesToWrite = 4;
257 0 : } else { bytesToWrite = 3;
258 0 : ch = UNI_REPLACEMENT_CHAR;
259 : }
260 :
261 0 : target += bytesToWrite;
262 0 : if (target > targetEnd) {
263 0 : source = oldSource; /* Back up source pointer! */
264 0 : target -= bytesToWrite; result = targetExhausted; break;
265 : }
266 0 : switch (bytesToWrite) { /* note: everything falls through. */
267 0 : case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
268 0 : case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
269 0 : case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
270 0 : case 1: *--target = (UTF8)(ch | firstByteMark[bytesToWrite]);
271 : }
272 0 : target += bytesToWrite;
273 : }
274 0 : *sourceStart = source;
275 0 : *targetStart = target;
276 0 : 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 0 : static Boolean isLegalUTF8(const UTF8 *source, int length) {
293 : UTF8 a;
294 0 : const UTF8 *srcptr = source+length;
295 0 : switch (length) {
296 0 : default: return false;
297 : /* Everything else falls through when "true"... */
298 0 : case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
299 0 : case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
300 0 : case 2: if ((a = (*--srcptr)) > 0xBF) return false;
301 :
302 0 : switch (*source) {
303 : /* no fall-through in this inner switch */
304 0 : case 0xE0: if (a < 0xA0) return false; break;
305 0 : case 0xED: if (a > 0x9F) return false; break;
306 0 : case 0xF0: if (a < 0x90) return false; break;
307 0 : case 0xF4: if (a > 0x8F) return false; break;
308 0 : default: if (a < 0x80) return false;
309 : }
310 :
311 0 : case 1: if (*source >= 0x80 && *source < 0xC2) return false;
312 : }
313 0 : if (*source > 0xF4) return false;
314 0 : 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 0 : Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd) {
324 0 : int length = trailingBytesForUTF8[*source]+1;
325 0 : if (source+length > sourceEnd) {
326 0 : return false;
327 : }
328 0 : return isLegalUTF8(source, length);
329 : }
330 :
331 : /* --------------------------------------------------------------------- */
332 :
333 0 : ConversionResult ConvertUTF8toUTF16 (const UTF8** sourceStart, const UTF8* sourceEnd,
334 : UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
335 0 : ConversionResult result = conversionOK;
336 0 : const UTF8* source = *sourceStart;
337 0 : UTF16* target = *targetStart;
338 0 : while (source < sourceEnd) {
339 0 : UTF32 ch = 0;
340 0 : unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
341 0 : if (source + extraBytesToRead >= sourceEnd) {
342 0 : result = sourceExhausted; break;
343 : }
344 : /* Do this check whether lenient or strict */
345 0 : if (! isLegalUTF8(source, extraBytesToRead+1)) {
346 0 : result = sourceIllegal;
347 0 : break;
348 : }
349 : /*
350 : * The cases all fall through. See "Note A" below.
351 : */
352 0 : switch (extraBytesToRead) {
353 0 : case 5: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
354 0 : case 4: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
355 0 : case 3: ch += *source++; ch <<= 6;
356 0 : case 2: ch += *source++; ch <<= 6;
357 0 : case 1: ch += *source++; ch <<= 6;
358 0 : case 0: ch += *source++;
359 : }
360 0 : ch -= offsetsFromUTF8[extraBytesToRead];
361 :
362 0 : if (target >= targetEnd) {
363 0 : source -= (extraBytesToRead+1); /* Back up source pointer! */
364 0 : result = targetExhausted; break;
365 : }
366 0 : if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
367 : /* UTF-16 surrogate values are illegal in UTF-32 */
368 0 : if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
369 0 : if (flags == strictConversion) {
370 0 : source -= (extraBytesToRead+1); /* return to the illegal value itself */
371 0 : result = sourceIllegal;
372 0 : break;
373 : } else {
374 0 : *target++ = UNI_REPLACEMENT_CHAR;
375 : }
376 : } else {
377 0 : *target++ = (UTF16)ch; /* normal case */
378 : }
379 0 : } else if (ch > UNI_MAX_UTF16) {
380 0 : if (flags == strictConversion) {
381 0 : result = sourceIllegal;
382 0 : source -= (extraBytesToRead+1); /* return to the start */
383 0 : break; /* Bail out; shouldn't continue */
384 : } else {
385 0 : *target++ = UNI_REPLACEMENT_CHAR;
386 : }
387 : } else {
388 : /* target is a character in range 0xFFFF - 0x10FFFF. */
389 0 : if (target + 1 >= targetEnd) {
390 0 : source -= (extraBytesToRead+1); /* Back up source pointer! */
391 0 : result = targetExhausted; break;
392 : }
393 0 : ch -= halfBase;
394 0 : *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
395 0 : *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
396 : }
397 : }
398 0 : *sourceStart = source;
399 0 : *targetStart = target;
400 0 : return result;
401 : }
402 :
403 : /* --------------------------------------------------------------------- */
404 :
405 0 : ConversionResult ConvertUTF32toUTF8 (const UTF32** sourceStart, const UTF32* sourceEnd,
406 : UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
407 0 : ConversionResult result = conversionOK;
408 0 : const UTF32* source = *sourceStart;
409 0 : UTF8* target = *targetStart;
410 0 : while (source < sourceEnd) {
411 : UTF32 ch;
412 0 : unsigned short bytesToWrite = 0;
413 0 : const UTF32 byteMask = 0xBF;
414 0 : const UTF32 byteMark = 0x80;
415 0 : ch = *source++;
416 0 : if (flags == strictConversion ) {
417 : /* UTF-16 surrogate values are illegal in UTF-32 */
418 0 : if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
419 0 : --source; /* return to the illegal value itself */
420 0 : result = sourceIllegal;
421 0 : 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 0 : if (ch < (UTF32)0x80) { bytesToWrite = 1;
429 0 : } else if (ch < (UTF32)0x800) { bytesToWrite = 2;
430 0 : } else if (ch < (UTF32)0x10000) { bytesToWrite = 3;
431 0 : } else if (ch <= UNI_MAX_LEGAL_UTF32) { bytesToWrite = 4;
432 0 : } else { bytesToWrite = 3;
433 0 : ch = UNI_REPLACEMENT_CHAR;
434 0 : result = sourceIllegal;
435 : }
436 :
437 0 : target += bytesToWrite;
438 0 : if (target > targetEnd) {
439 0 : --source; /* Back up source pointer! */
440 0 : target -= bytesToWrite; result = targetExhausted; break;
441 : }
442 0 : switch (bytesToWrite) { /* note: everything falls through. */
443 0 : case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
444 0 : case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
445 0 : case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
446 0 : case 1: *--target = (UTF8) (ch | firstByteMark[bytesToWrite]);
447 : }
448 0 : target += bytesToWrite;
449 : }
450 0 : *sourceStart = source;
451 0 : *targetStart = target;
452 0 : return result;
453 : }
454 :
455 : /* --------------------------------------------------------------------- */
456 :
457 0 : ConversionResult ConvertUTF8toUTF32 (const UTF8** sourceStart, const UTF8* sourceEnd,
458 : UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
459 0 : ConversionResult result = conversionOK;
460 0 : const UTF8* source = *sourceStart;
461 0 : UTF32* target = *targetStart;
462 0 : while (source < sourceEnd) {
463 0 : UTF32 ch = 0;
464 0 : unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
465 0 : if (source + extraBytesToRead >= sourceEnd) {
466 0 : result = sourceExhausted; break;
467 : }
468 : /* Do this check whether lenient or strict */
469 0 : if (! isLegalUTF8(source, extraBytesToRead+1)) {
470 0 : result = sourceIllegal;
471 0 : break;
472 : }
473 : /*
474 : * The cases all fall through. See "Note A" below.
475 : */
476 0 : switch (extraBytesToRead) {
477 0 : case 5: ch += *source++; ch <<= 6;
478 0 : case 4: ch += *source++; ch <<= 6;
479 0 : case 3: ch += *source++; ch <<= 6;
480 0 : case 2: ch += *source++; ch <<= 6;
481 0 : case 1: ch += *source++; ch <<= 6;
482 0 : case 0: ch += *source++;
483 : }
484 0 : ch -= offsetsFromUTF8[extraBytesToRead];
485 :
486 0 : if (target >= targetEnd) {
487 0 : source -= (extraBytesToRead+1); /* Back up the source pointer! */
488 0 : result = targetExhausted; break;
489 : }
490 0 : 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 0 : if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
496 0 : if (flags == strictConversion) {
497 0 : source -= (extraBytesToRead+1); /* return to the illegal value itself */
498 0 : result = sourceIllegal;
499 0 : break;
500 : } else {
501 0 : *target++ = UNI_REPLACEMENT_CHAR;
502 : }
503 : } else {
504 0 : *target++ = ch;
505 : }
506 : } else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */
507 0 : result = sourceIllegal;
508 0 : *target++ = UNI_REPLACEMENT_CHAR;
509 : }
510 : }
511 0 : *sourceStart = source;
512 0 : *targetStart = target;
513 0 : 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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