1 /*===--- ConvertUTF.c - Universal Character Names conversions ---------------===
3 * The LLVM Compiler Infrastructure
5 * This file is distributed under the University of Illinois Open Source
6 * License. See LICENSE.TXT for details.
8 *===------------------------------------------------------------------------=*/
10 * Copyright 2001-2004 Unicode, Inc.
14 * This source code is provided as is by Unicode, Inc. No claims are
15 * made as to fitness for any particular purpose. No warranties of any
16 * kind are expressed or implied. The recipient agrees to determine
17 * applicability of information provided. If this file has been
18 * purchased on magnetic or optical media from Unicode, Inc., the
19 * sole remedy for any claim will be exchange of defective media
20 * within 90 days of receipt.
22 * Limitations on Rights to Redistribute This Code
24 * Unicode, Inc. hereby grants the right to freely use the information
25 * supplied in this file in the creation of products supporting the
26 * Unicode Standard, and to make copies of this file in any form
27 * for internal or external distribution as long as this notice
31 /* ---------------------------------------------------------------------
33 Conversions between UTF32, UTF-16, and UTF-8. Source code file.
34 Author: Mark E. Davis, 1994.
35 Rev History: Rick McGowan, fixes & updates May 2001.
36 Sept 2001: fixed const & error conditions per
37 mods suggested by S. Parent & A. Lillich.
38 June 2002: Tim Dodd added detection and handling of incomplete
39 source sequences, enhanced error detection, added casts
40 to eliminate compiler warnings.
41 July 2003: slight mods to back out aggressive FFFE detection.
42 Jan 2004: updated switches in from-UTF8 conversions.
43 Oct 2004: updated to use UNI_MAX_LEGAL_UTF32 in UTF-32 conversions.
45 See the header file "ConvertUTF.h" for complete documentation.
47 ------------------------------------------------------------------------ */
50 #include "llvm/Support/ConvertUTF.h"
55 static const int halfShift = 10; /* used for shifting by 10 bits */
57 static const UTF32 halfBase = 0x0010000UL;
58 static const UTF32 halfMask = 0x3FFUL;
60 #define UNI_SUR_HIGH_START (UTF32)0xD800
61 #define UNI_SUR_HIGH_END (UTF32)0xDBFF
62 #define UNI_SUR_LOW_START (UTF32)0xDC00
63 #define UNI_SUR_LOW_END (UTF32)0xDFFF
67 /* --------------------------------------------------------------------- */
70 * Index into the table below with the first byte of a UTF-8 sequence to
71 * get the number of trailing bytes that are supposed to follow it.
72 * Note that *legal* UTF-8 values can't have 4 or 5-bytes. The table is
73 * left as-is for anyone who may want to do such conversion, which was
74 * allowed in earlier algorithms.
76 static const char trailingBytesForUTF8[256] = {
77 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,
78 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,
79 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,
80 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,
81 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,
82 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,
83 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,
84 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
88 * Magic values subtracted from a buffer value during UTF8 conversion.
89 * This table contains as many values as there might be trailing bytes
90 * in a UTF-8 sequence.
92 static const UTF32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL,
93 0x03C82080UL, 0xFA082080UL, 0x82082080UL };
96 * Once the bits are split out into bytes of UTF-8, this is a mask OR-ed
97 * into the first byte, depending on how many bytes follow. There are
98 * as many entries in this table as there are UTF-8 sequence types.
99 * (I.e., one byte sequence, two byte... etc.). Remember that sequencs
100 * for *legal* UTF-8 will be 4 or fewer bytes total.
102 static const UTF8 firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
104 /* --------------------------------------------------------------------- */
106 /* The interface converts a whole buffer to avoid function-call overhead.
107 * Constants have been gathered. Loops & conditionals have been removed as
108 * much as possible for efficiency, in favor of drop-through switches.
109 * (See "Note A" at the bottom of the file for equivalent code.)
110 * If your compiler supports it, the "isLegalUTF8" call can be turned
111 * into an inline function.
115 /* --------------------------------------------------------------------- */
117 ConversionResult ConvertUTF32toUTF16 (
118 const UTF32** sourceStart, const UTF32* sourceEnd,
119 UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
120 ConversionResult result = conversionOK;
121 const UTF32* source = *sourceStart;
122 UTF16* target = *targetStart;
123 while (source < sourceEnd) {
125 if (target >= targetEnd) {
126 result = targetExhausted; break;
129 if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
130 /* UTF-16 surrogate values are illegal in UTF-32; 0xffff or 0xfffe are both reserved values */
131 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
132 if (flags == strictConversion) {
133 --source; /* return to the illegal value itself */
134 result = sourceIllegal;
137 *target++ = UNI_REPLACEMENT_CHAR;
140 *target++ = (UTF16)ch; /* normal case */
142 } else if (ch > UNI_MAX_LEGAL_UTF32) {
143 if (flags == strictConversion) {
144 result = sourceIllegal;
146 *target++ = UNI_REPLACEMENT_CHAR;
149 /* target is a character in range 0xFFFF - 0x10FFFF. */
150 if (target + 1 >= targetEnd) {
151 --source; /* Back up source pointer! */
152 result = targetExhausted; break;
155 *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
156 *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
159 *sourceStart = source;
160 *targetStart = target;
164 /* --------------------------------------------------------------------- */
166 ConversionResult ConvertUTF16toUTF32 (
167 const UTF16** sourceStart, const UTF16* sourceEnd,
168 UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
169 ConversionResult result = conversionOK;
170 const UTF16* source = *sourceStart;
171 UTF32* target = *targetStart;
173 while (source < sourceEnd) {
174 const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
176 /* If we have a surrogate pair, convert to UTF32 first. */
177 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) {
178 /* If the 16 bits following the high surrogate are in the source buffer... */
179 if (source < sourceEnd) {
181 /* If it's a low surrogate, convert to UTF32. */
182 if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
183 ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
184 + (ch2 - UNI_SUR_LOW_START) + halfBase;
186 } else if (flags == strictConversion) { /* it's an unpaired high surrogate */
187 --source; /* return to the illegal value itself */
188 result = sourceIllegal;
191 } else { /* We don't have the 16 bits following the high surrogate. */
192 --source; /* return to the high surrogate */
193 result = sourceExhausted;
196 } else if (flags == strictConversion) {
197 /* UTF-16 surrogate values are illegal in UTF-32 */
198 if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
199 --source; /* return to the illegal value itself */
200 result = sourceIllegal;
204 if (target >= targetEnd) {
205 source = oldSource; /* Back up source pointer! */
206 result = targetExhausted; break;
210 *sourceStart = source;
211 *targetStart = target;
213 if (result == sourceIllegal) {
214 fprintf(stderr, "ConvertUTF16toUTF32 illegal seq 0x%04x,%04x\n", ch, ch2);
220 ConversionResult ConvertUTF16toUTF8 (
221 const UTF16** sourceStart, const UTF16* sourceEnd,
222 UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
223 ConversionResult result = conversionOK;
224 const UTF16* source = *sourceStart;
225 UTF8* target = *targetStart;
226 while (source < sourceEnd) {
228 unsigned short bytesToWrite = 0;
229 const UTF32 byteMask = 0xBF;
230 const UTF32 byteMark = 0x80;
231 const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
233 /* If we have a surrogate pair, convert to UTF32 first. */
234 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) {
235 /* If the 16 bits following the high surrogate are in the source buffer... */
236 if (source < sourceEnd) {
238 /* If it's a low surrogate, convert to UTF32. */
239 if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
240 ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
241 + (ch2 - UNI_SUR_LOW_START) + halfBase;
243 } else if (flags == strictConversion) { /* it's an unpaired high surrogate */
244 --source; /* return to the illegal value itself */
245 result = sourceIllegal;
248 } else { /* We don't have the 16 bits following the high surrogate. */
249 --source; /* return to the high surrogate */
250 result = sourceExhausted;
253 } else if (flags == strictConversion) {
254 /* UTF-16 surrogate values are illegal in UTF-32 */
255 if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
256 --source; /* return to the illegal value itself */
257 result = sourceIllegal;
261 /* Figure out how many bytes the result will require */
262 if (ch < (UTF32)0x80) { bytesToWrite = 1;
263 } else if (ch < (UTF32)0x800) { bytesToWrite = 2;
264 } else if (ch < (UTF32)0x10000) { bytesToWrite = 3;
265 } else if (ch < (UTF32)0x110000) { bytesToWrite = 4;
266 } else { bytesToWrite = 3;
267 ch = UNI_REPLACEMENT_CHAR;
270 target += bytesToWrite;
271 if (target > targetEnd) {
272 source = oldSource; /* Back up source pointer! */
273 target -= bytesToWrite; result = targetExhausted; break;
275 switch (bytesToWrite) { /* note: everything falls through. */
276 case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
277 case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
278 case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
279 case 1: *--target = (UTF8)(ch | firstByteMark[bytesToWrite]);
281 target += bytesToWrite;
283 *sourceStart = source;
284 *targetStart = target;
288 /* --------------------------------------------------------------------- */
290 ConversionResult ConvertUTF32toUTF8 (
291 const UTF32** sourceStart, const UTF32* sourceEnd,
292 UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
293 ConversionResult result = conversionOK;
294 const UTF32* source = *sourceStart;
295 UTF8* target = *targetStart;
296 while (source < sourceEnd) {
298 unsigned short bytesToWrite = 0;
299 const UTF32 byteMask = 0xBF;
300 const UTF32 byteMark = 0x80;
302 if (flags == strictConversion ) {
303 /* UTF-16 surrogate values are illegal in UTF-32 */
304 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
305 --source; /* return to the illegal value itself */
306 result = sourceIllegal;
311 * Figure out how many bytes the result will require. Turn any
312 * illegally large UTF32 things (> Plane 17) into replacement chars.
314 if (ch < (UTF32)0x80) { bytesToWrite = 1;
315 } else if (ch < (UTF32)0x800) { bytesToWrite = 2;
316 } else if (ch < (UTF32)0x10000) { bytesToWrite = 3;
317 } else if (ch <= UNI_MAX_LEGAL_UTF32) { bytesToWrite = 4;
318 } else { bytesToWrite = 3;
319 ch = UNI_REPLACEMENT_CHAR;
320 result = sourceIllegal;
323 target += bytesToWrite;
324 if (target > targetEnd) {
325 --source; /* Back up source pointer! */
326 target -= bytesToWrite; result = targetExhausted; break;
328 switch (bytesToWrite) { /* note: everything falls through. */
329 case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
330 case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
331 case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
332 case 1: *--target = (UTF8) (ch | firstByteMark[bytesToWrite]);
334 target += bytesToWrite;
336 *sourceStart = source;
337 *targetStart = target;
341 /* --------------------------------------------------------------------- */
344 * Utility routine to tell whether a sequence of bytes is legal UTF-8.
345 * This must be called with the length pre-determined by the first byte.
346 * If not calling this from ConvertUTF8to*, then the length can be set by:
347 * length = trailingBytesForUTF8[*source]+1;
348 * and the sequence is illegal right away if there aren't that many bytes
350 * If presented with a length > 4, this returns false. The Unicode
351 * definition of UTF-8 goes up to 4-byte sequences.
354 static Boolean isLegalUTF8(const UTF8 *source, int length) {
356 const UTF8 *srcptr = source+length;
358 default: return false;
359 /* Everything else falls through when "true"... */
360 case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
361 case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
362 case 2: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
365 /* no fall-through in this inner switch */
366 case 0xE0: if (a < 0xA0) return false; break;
367 case 0xED: if (a > 0x9F) return false; break;
368 case 0xF0: if (a < 0x90) return false; break;
369 case 0xF4: if (a > 0x8F) return false; break;
370 default: if (a < 0x80) return false;
373 case 1: if (*source >= 0x80 && *source < 0xC2) return false;
375 if (*source > 0xF4) return false;
379 /* --------------------------------------------------------------------- */
382 * Exported function to return whether a UTF-8 sequence is legal or not.
383 * This is not used here; it's just exported.
385 Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd) {
386 int length = trailingBytesForUTF8[*source]+1;
387 if (length > sourceEnd - source) {
390 return isLegalUTF8(source, length);
393 /* --------------------------------------------------------------------- */
396 * Exported function to return the total number of bytes in a codepoint
397 * represented in UTF-8, given the value of the first byte.
399 unsigned getNumBytesForUTF8(UTF8 first) {
400 return trailingBytesForUTF8[first] + 1;
403 /* --------------------------------------------------------------------- */
406 * Exported function to return whether a UTF-8 string is legal or not.
407 * This is not used here; it's just exported.
409 Boolean isLegalUTF8String(const UTF8 **source, const UTF8 *sourceEnd) {
410 while (*source != sourceEnd) {
411 int length = trailingBytesForUTF8[**source] + 1;
412 if (length > sourceEnd - *source || !isLegalUTF8(*source, length))
419 /* --------------------------------------------------------------------- */
421 ConversionResult ConvertUTF8toUTF16 (
422 const UTF8** sourceStart, const UTF8* sourceEnd,
423 UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
424 ConversionResult result = conversionOK;
425 const UTF8* source = *sourceStart;
426 UTF16* target = *targetStart;
427 while (source < sourceEnd) {
429 unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
430 if (extraBytesToRead >= sourceEnd - source) {
431 result = sourceExhausted; break;
433 /* Do this check whether lenient or strict */
434 if (!isLegalUTF8(source, extraBytesToRead+1)) {
435 result = sourceIllegal;
439 * The cases all fall through. See "Note A" below.
441 switch (extraBytesToRead) {
442 case 5: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
443 case 4: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
444 case 3: ch += *source++; ch <<= 6;
445 case 2: ch += *source++; ch <<= 6;
446 case 1: ch += *source++; ch <<= 6;
447 case 0: ch += *source++;
449 ch -= offsetsFromUTF8[extraBytesToRead];
451 if (target >= targetEnd) {
452 source -= (extraBytesToRead+1); /* Back up source pointer! */
453 result = targetExhausted; break;
455 if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
456 /* UTF-16 surrogate values are illegal in UTF-32 */
457 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
458 if (flags == strictConversion) {
459 source -= (extraBytesToRead+1); /* return to the illegal value itself */
460 result = sourceIllegal;
463 *target++ = UNI_REPLACEMENT_CHAR;
466 *target++ = (UTF16)ch; /* normal case */
468 } else if (ch > UNI_MAX_UTF16) {
469 if (flags == strictConversion) {
470 result = sourceIllegal;
471 source -= (extraBytesToRead+1); /* return to the start */
472 break; /* Bail out; shouldn't continue */
474 *target++ = UNI_REPLACEMENT_CHAR;
477 /* target is a character in range 0xFFFF - 0x10FFFF. */
478 if (target + 1 >= targetEnd) {
479 source -= (extraBytesToRead+1); /* Back up source pointer! */
480 result = targetExhausted; break;
483 *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
484 *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
487 *sourceStart = source;
488 *targetStart = target;
492 /* --------------------------------------------------------------------- */
494 ConversionResult ConvertUTF8toUTF32 (
495 const UTF8** sourceStart, const UTF8* sourceEnd,
496 UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
497 ConversionResult result = conversionOK;
498 const UTF8* source = *sourceStart;
499 UTF32* target = *targetStart;
500 while (source < sourceEnd) {
502 unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
503 if (extraBytesToRead >= sourceEnd - source) {
504 result = sourceExhausted; break;
506 /* Do this check whether lenient or strict */
507 if (!isLegalUTF8(source, extraBytesToRead+1)) {
508 result = sourceIllegal;
512 * The cases all fall through. See "Note A" below.
514 switch (extraBytesToRead) {
515 case 5: ch += *source++; ch <<= 6;
516 case 4: ch += *source++; ch <<= 6;
517 case 3: ch += *source++; ch <<= 6;
518 case 2: ch += *source++; ch <<= 6;
519 case 1: ch += *source++; ch <<= 6;
520 case 0: ch += *source++;
522 ch -= offsetsFromUTF8[extraBytesToRead];
524 if (target >= targetEnd) {
525 source -= (extraBytesToRead+1); /* Back up the source pointer! */
526 result = targetExhausted; break;
528 if (ch <= UNI_MAX_LEGAL_UTF32) {
530 * UTF-16 surrogate values are illegal in UTF-32, and anything
531 * over Plane 17 (> 0x10FFFF) is illegal.
533 if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
534 if (flags == strictConversion) {
535 source -= (extraBytesToRead+1); /* return to the illegal value itself */
536 result = sourceIllegal;
539 *target++ = UNI_REPLACEMENT_CHAR;
544 } else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */
545 result = sourceIllegal;
546 *target++ = UNI_REPLACEMENT_CHAR;
549 *sourceStart = source;
550 *targetStart = target;
554 /* ---------------------------------------------------------------------
557 The fall-through switches in UTF-8 reading code save a
558 temp variable, some decrements & conditionals. The switches
559 are equivalent to the following loop:
561 int tmpBytesToRead = extraBytesToRead+1;
565 if (tmpBytesToRead) ch <<= 6;
566 } while (tmpBytesToRead > 0);
568 In UTF-8 writing code, the switches on "bytesToWrite" are
569 similarly unrolled loops.
571 --------------------------------------------------------------------- */