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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    May 2006: updated isLegalUTF8Sequence.
37
38    See the header file "ConvertUTF.h" for complete documentation.
39
40------------------------------------------------------------------------ */
41
42#ifdef CVTUTF_DEBUG
43 #include <stdio.h>
44#endif
45#include <string.h> /* strlen() */
46#include "ConvertUTF.h"
47
48static const int halfShift  = 10; /* used for shifting by 10 bits */
49
50static const UTF32 halfBase = 0x0010000UL;
51static const UTF32 halfMask = 0x3FFUL;
52
53#define UNI_SUR_HIGH_START  (UTF32)0xD800
54#define UNI_SUR_HIGH_END    (UTF32)0xDBFF
55#define UNI_SUR_LOW_START   (UTF32)0xDC00
56#define UNI_SUR_LOW_END     (UTF32)0xDFFF
57#define false	   0
58#define true	    1
59
60/* --------------------------------------------------------------------- */
61
62ConversionResult ConvertUTF32toUTF16 (
63	const UTF32** sourceStart, const UTF32* sourceEnd,
64	UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
65    ConversionResult result = conversionOK;
66    const UTF32* source = *sourceStart;
67    UTF16* target = *targetStart;
68    while (source < sourceEnd) {
69	UTF32 ch;
70	if (target >= targetEnd) {
71	    result = targetExhausted; break;
72	}
73	ch = *source++;
74	if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
75	    /* UTF-16 surrogate values are illegal in UTF-32; 0xffff or 0xfffe are both reserved values */
76	    if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
77		if (flags == strictConversion) {
78		    --source; /* return to the illegal value itself */
79		    result = sourceIllegal;
80		    break;
81		} else {
82		    *target++ = UNI_REPLACEMENT_CHAR;
83		}
84	    } else {
85		*target++ = (UTF16)ch; /* normal case */
86	    }
87	} else if (ch > UNI_MAX_LEGAL_UTF32) {
88	    if (flags == strictConversion) {
89		result = sourceIllegal;
90	    } else {
91		*target++ = UNI_REPLACEMENT_CHAR;
92	    }
93	} else {
94	    /* target is a character in range 0xFFFF - 0x10FFFF. */
95	    if (target + 1 >= targetEnd) {
96		--source; /* Back up source pointer! */
97		result = targetExhausted; break;
98	    }
99	    ch -= halfBase;
100	    *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
101	    *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
102	}
103    }
104    *sourceStart = source;
105    *targetStart = target;
106    return result;
107}
108
109/* --------------------------------------------------------------------- */
110
111ConversionResult ConvertUTF16toUTF32 (
112	const UTF16** sourceStart, const UTF16* sourceEnd,
113	UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
114    ConversionResult result = conversionOK;
115    const UTF16* source = *sourceStart;
116    UTF32* target = *targetStart;
117    UTF32 ch, ch2;
118    while (source < sourceEnd) {
119	const UTF16* oldSource = source; /*  In case we have to back up because of target overflow. */
120	ch = *source++;
121	/* If we have a surrogate pair, convert to UTF32 first. */
122	if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) {
123	    /* If the 16 bits following the high surrogate are in the source buffer... */
124	    if (source < sourceEnd) {
125		ch2 = *source;
126		/* If it's a low surrogate, convert to UTF32. */
127		if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
128		    ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
129			+ (ch2 - UNI_SUR_LOW_START) + halfBase;
130		    ++source;
131		} else if (flags == strictConversion) { /* it's an unpaired high surrogate */
132		    --source; /* return to the illegal value itself */
133		    result = sourceIllegal;
134		    break;
135		}
136	    } else { /* We don't have the 16 bits following the high surrogate. */
137		--source; /* return to the high surrogate */
138		result = sourceExhausted;
139		break;
140	    }
141	} else if (flags == strictConversion) {
142	    /* UTF-16 surrogate values are illegal in UTF-32 */
143	    if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
144		--source; /* return to the illegal value itself */
145		result = sourceIllegal;
146		break;
147	    }
148	}
149	if (target >= targetEnd) {
150	    source = oldSource; /* Back up source pointer! */
151	    result = targetExhausted; break;
152	}
153	*target++ = ch;
154    }
155    *sourceStart = source;
156    *targetStart = target;
157#ifdef CVTUTF_DEBUG
158if (result == sourceIllegal) {
159    fprintf(stderr, "ConvertUTF16toUTF32 illegal seq 0x%04x,%04x\n", ch, ch2);
160    fflush(stderr);
161}
162#endif
163    return result;
164}
165
166/* --------------------------------------------------------------------- */
167
168/*
169 * Index into the table below with the first byte of a UTF-8 sequence to
170 * get the number of trailing bytes that are supposed to follow it.
171 * Note that *legal* UTF-8 values can't have 4 or 5-bytes. The table is
172 * left as-is for anyone who may want to do such conversion, which was
173 * allowed in earlier algorithms.
174 */
175static const char trailingBytesForUTF8[256] = {
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    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,
180    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,
181    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,
182    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,
183    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
184};
185
186/*
187 * Magic values subtracted from a buffer value during UTF8 conversion.
188 * This table contains as many values as there might be trailing bytes
189 * in a UTF-8 sequence.
190 */
191static const UTF32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL,
192		     0x03C82080UL, 0xFA082080UL, 0x82082080UL };
193
194/*
195 * Once the bits are split out into bytes of UTF-8, this is a mask OR-ed
196 * into the first byte, depending on how many bytes follow. There are
197 * as many entries in this table as there are UTF-8 sequence types.
198 * (I.e., one byte sequence, two byte... etc.). Remember that sequencs
199 * for *legal* UTF-8 will be 4 or fewer bytes total.
200 */
201static const UTF8 firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
202
203/* --------------------------------------------------------------------- */
204
205/* The interface converts a whole buffer to avoid function-call overhead.
206 * Constants have been gathered. Loops & conditionals have been removed as
207 * much as possible for efficiency, in favor of drop-through switches.
208 * (See "Note A" at the bottom of the file for equivalent code.)
209 * If your compiler supports it, the "isLegalUTF8" call can be turned
210 * into an inline function.
211 */
212
213/* --------------------------------------------------------------------- */
214
215ConversionResult ConvertUTF16toUTF8 (
216	const UTF16** sourceStart, const UTF16* sourceEnd,
217	UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
218    ConversionResult result = conversionOK;
219    const UTF16* source = *sourceStart;
220    UTF8* target = *targetStart;
221    while (source < sourceEnd) {
222	UTF32 ch;
223	unsigned short bytesToWrite = 0;
224	const UTF32 byteMask = 0xBF;
225	const UTF32 byteMark = 0x80;
226	const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
227	ch = *source++;
228	/* If we have a surrogate pair, convert to UTF32 first. */
229	if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) {
230	    /* If the 16 bits following the high surrogate are in the source buffer... */
231	    if (source < sourceEnd) {
232		UTF32 ch2 = *source;
233		/* If it's a low surrogate, convert to UTF32. */
234		if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
235		    ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
236			+ (ch2 - UNI_SUR_LOW_START) + halfBase;
237		    ++source;
238		} else if (flags == strictConversion) { /* it's an unpaired high surrogate */
239		    --source; /* return to the illegal value itself */
240		    result = sourceIllegal;
241		    break;
242		}
243	    } else { /* We don't have the 16 bits following the high surrogate. */
244		--source; /* return to the high surrogate */
245		result = sourceExhausted;
246		break;
247	    }
248	} else if (flags == strictConversion) {
249	    /* UTF-16 surrogate values are illegal in UTF-32 */
250	    if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
251		--source; /* return to the illegal value itself */
252		result = sourceIllegal;
253		break;
254	    }
255	}
256	/* Figure out how many bytes the result will require */
257	if (ch < (UTF32)0x80) {	     bytesToWrite = 1;
258	} else if (ch < (UTF32)0x800) {     bytesToWrite = 2;
259	} else if (ch < (UTF32)0x10000) {   bytesToWrite = 3;
260	} else if (ch < (UTF32)0x110000) {  bytesToWrite = 4;
261	} else {			    bytesToWrite = 3;
262					    ch = UNI_REPLACEMENT_CHAR;
263	}
264
265	target += bytesToWrite;
266	if (target > targetEnd) {
267	    source = oldSource; /* Back up source pointer! */
268	    target -= bytesToWrite; result = targetExhausted; break;
269	}
270	switch (bytesToWrite) { /* note: everything falls through. */
271	    case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
272	    case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
273	    case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
274	    case 1: *--target =  (UTF8)(ch | firstByteMark[bytesToWrite]);
275	}
276	target += bytesToWrite;
277    }
278    *sourceStart = source;
279    *targetStart = target;
280    return result;
281}
282
283/* --------------------------------------------------------------------- */
284
285/*
286 * Utility routine to tell whether a sequence of bytes is legal UTF-8.
287 * This must be called with the length pre-determined by the first byte.
288 * If not calling this from ConvertUTF8to*, then the length can be set by:
289 *  length = trailingBytesForUTF8[*source]+1;
290 * and the sequence is illegal right away if there aren't that many bytes
291 * available.
292 * If presented with a length > 4, this returns false. The Unicode
293 * definition of UTF-8 goes up to 4-byte sequences.
294 */
295
296static Boolean isLegalUTF8(const UTF8 *source, int length) {
297    UTF8 a;
298    const UTF8 *srcptr = source+length;
299    switch (length) {
300    default: return false;
301	/* Everything else falls through when "true"... */
302    case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
303    case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
304    case 2: if ((a = (*--srcptr)) > 0xBF) return false;
305
306	switch (*source) {
307	    /* no fall-through in this inner switch */
308	    case 0xE0: if (a < 0xA0) return false; break;
309	    case 0xED: if ((a < 0x80) || (a > 0x9F)) return false; break;
310	    case 0xF0: if (a < 0x90) return false; break;
311	    case 0xF4: if (a > 0x8F) return false; break;
312	    default:   if (a < 0x80) return false;
313	}
314
315    case 1: if (*source >= 0x80 && *source < 0xC2) return false;
316    }
317    if (*source > 0xF4) return false;
318    return true;
319}
320
321/* --------------------------------------------------------------------- */
322
323/*
324 * Exported function to return whether a UTF-8 sequence is legal or not.
325 * This is not used here; it's just exported.
326 */
327
328Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd) {
329    int length;
330    if (source == sourceEnd) {
331        return true;
332    }
333    while (true) {
334        length = trailingBytesForUTF8[*source]+1;
335        if (source+length > sourceEnd) {
336            return false;
337        }
338        if (!isLegalUTF8(source, length)) {
339            return false;
340        }
341        source += length;
342        if (source >= sourceEnd) {
343            return true;
344        }
345    }
346}
347
348/**
349 * This is a variation of isLegalUTF8Sequence() that behaves like g_utf8_validate().
350 * In addition to knowing if the sequence is legal, it also tells you the last good character.
351 */
352Boolean
353tr_utf8_validate( const char * str, int max_len, const char ** end )
354{
355    const UTF8* source = (const UTF8*) str;
356    const UTF8* sourceEnd;
357
358    if( max_len == 0 )
359        return true;
360
361    if( str == NULL )
362        return false;
363
364    sourceEnd = source + ((max_len < 0) ? strlen(str) : (size_t)max_len);
365
366    if( source == sourceEnd )
367    {
368        if( end != NULL )
369            *end = (const char*) source;
370        return true;
371    }
372
373    for( ;; )
374    {
375        const int length = trailingBytesForUTF8[*source] + 1;
376        if (source + length > sourceEnd) {
377            if( end != NULL )
378                *end = (const char*) source;
379            return false;
380        }
381        if (!isLegalUTF8(source, length)) {
382            if( end != NULL )
383                *end = (const char*) source;
384            return false;
385        }
386        source += length;
387        if (source >= sourceEnd) {
388            if( end != NULL )
389                *end = (const char*) source;
390            return true;
391        }
392    }
393
394
395}
396
397
398/* --------------------------------------------------------------------- */
399
400ConversionResult ConvertUTF8toUTF16 (
401	const UTF8** sourceStart, const UTF8* sourceEnd,
402	UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
403    ConversionResult result = conversionOK;
404    const UTF8* source = *sourceStart;
405    UTF16* target = *targetStart;
406    while (source < sourceEnd) {
407	UTF32 ch = 0;
408	unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
409	if (source + extraBytesToRead >= sourceEnd) {
410	    result = sourceExhausted; break;
411	}
412	/* Do this check whether lenient or strict */
413	if (! isLegalUTF8(source, extraBytesToRead+1)) {
414	    result = sourceIllegal;
415	    break;
416	}
417	/*
418	 * The cases all fall through. See "Note A" below.
419	 */
420	switch (extraBytesToRead) {
421	    case 5: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
422	    case 4: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
423	    case 3: ch += *source++; ch <<= 6;
424	    case 2: ch += *source++; ch <<= 6;
425	    case 1: ch += *source++; ch <<= 6;
426	    case 0: ch += *source++;
427	}
428	ch -= offsetsFromUTF8[extraBytesToRead];
429
430	if (target >= targetEnd) {
431	    source -= (extraBytesToRead+1); /* Back up source pointer! */
432	    result = targetExhausted; break;
433	}
434	if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
435	    /* UTF-16 surrogate values are illegal in UTF-32 */
436	    if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
437		if (flags == strictConversion) {
438		    source -= (extraBytesToRead+1); /* return to the illegal value itself */
439		    result = sourceIllegal;
440		    break;
441		} else {
442		    *target++ = UNI_REPLACEMENT_CHAR;
443		}
444	    } else {
445		*target++ = (UTF16)ch; /* normal case */
446	    }
447	} else if (ch > UNI_MAX_UTF16) {
448	    if (flags == strictConversion) {
449		result = sourceIllegal;
450		source -= (extraBytesToRead+1); /* return to the start */
451		break; /* Bail out; shouldn't continue */
452	    } else {
453		*target++ = UNI_REPLACEMENT_CHAR;
454	    }
455	} else {
456	    /* target is a character in range 0xFFFF - 0x10FFFF. */
457	    if (target + 1 >= targetEnd) {
458		source -= (extraBytesToRead+1); /* Back up source pointer! */
459		result = targetExhausted; break;
460	    }
461	    ch -= halfBase;
462	    *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
463	    *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
464	}
465    }
466    *sourceStart = source;
467    *targetStart = target;
468    return result;
469}
470
471/* --------------------------------------------------------------------- */
472
473ConversionResult ConvertUTF32toUTF8 (
474	const UTF32** sourceStart, const UTF32* sourceEnd,
475	UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
476    ConversionResult result = conversionOK;
477    const UTF32* source = *sourceStart;
478    UTF8* target = *targetStart;
479    while (source < sourceEnd) {
480	UTF32 ch;
481	unsigned short bytesToWrite = 0;
482	const UTF32 byteMask = 0xBF;
483	const UTF32 byteMark = 0x80;
484	ch = *source++;
485	if (flags == strictConversion ) {
486	    /* UTF-16 surrogate values are illegal in UTF-32 */
487	    if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
488		--source; /* return to the illegal value itself */
489		result = sourceIllegal;
490		break;
491	    }
492	}
493	/*
494	 * Figure out how many bytes the result will require. Turn any
495	 * illegally large UTF32 things (> Plane 17) into replacement chars.
496	 */
497	if (ch < (UTF32)0x80) {	     bytesToWrite = 1;
498	} else if (ch < (UTF32)0x800) {     bytesToWrite = 2;
499	} else if (ch < (UTF32)0x10000) {   bytesToWrite = 3;
500	} else if (ch <= UNI_MAX_LEGAL_UTF32) {  bytesToWrite = 4;
501	} else {			    bytesToWrite = 3;
502					    ch = UNI_REPLACEMENT_CHAR;
503					    result = sourceIllegal;
504	}
505
506	target += bytesToWrite;
507	if (target > targetEnd) {
508	    --source; /* Back up source pointer! */
509	    target -= bytesToWrite; result = targetExhausted; break;
510	}
511	switch (bytesToWrite) { /* note: everything falls through. */
512	    case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
513	    case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
514	    case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
515	    case 1: *--target = (UTF8) (ch | firstByteMark[bytesToWrite]);
516	}
517	target += bytesToWrite;
518    }
519    *sourceStart = source;
520    *targetStart = target;
521    return result;
522}
523
524/* --------------------------------------------------------------------- */
525
526ConversionResult ConvertUTF8toUTF32 (
527	const UTF8** sourceStart, const UTF8* sourceEnd,
528	UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
529    ConversionResult result = conversionOK;
530    const UTF8* source = *sourceStart;
531    UTF32* target = *targetStart;
532    while (source < sourceEnd) {
533	UTF32 ch = 0;
534	unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
535	if (source + extraBytesToRead >= sourceEnd) {
536	    result = sourceExhausted; break;
537	}
538	/* Do this check whether lenient or strict */
539	if (! isLegalUTF8(source, extraBytesToRead+1)) {
540	    result = sourceIllegal;
541	    break;
542	}
543	/*
544	 * The cases all fall through. See "Note A" below.
545	 */
546	switch (extraBytesToRead) {
547	    case 5: ch += *source++; ch <<= 6;
548	    case 4: ch += *source++; ch <<= 6;
549	    case 3: ch += *source++; ch <<= 6;
550	    case 2: ch += *source++; ch <<= 6;
551	    case 1: ch += *source++; ch <<= 6;
552	    case 0: ch += *source++;
553	}
554	ch -= offsetsFromUTF8[extraBytesToRead];
555
556	if (target >= targetEnd) {
557	    source -= (extraBytesToRead+1); /* Back up the source pointer! */
558	    result = targetExhausted; break;
559	}
560	if (ch <= UNI_MAX_LEGAL_UTF32) {
561	    /*
562	     * UTF-16 surrogate values are illegal in UTF-32, and anything
563	     * over Plane 17 (> 0x10FFFF) is illegal.
564	     */
565	    if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
566		if (flags == strictConversion) {
567		    source -= (extraBytesToRead+1); /* return to the illegal value itself */
568		    result = sourceIllegal;
569		    break;
570		} else {
571		    *target++ = UNI_REPLACEMENT_CHAR;
572		}
573	    } else {
574		*target++ = ch;
575	    }
576	} else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */
577	    result = sourceIllegal;
578	    *target++ = UNI_REPLACEMENT_CHAR;
579	}
580    }
581    *sourceStart = source;
582    *targetStart = target;
583    return result;
584}
585
586/* ---------------------------------------------------------------------
587
588    Note A.
589    The fall-through switches in UTF-8 reading code save a
590    temp variable, some decrements & conditionals. The switches
591    are equivalent to the following loop:
592	{
593	    int tmpBytesToRead = extraBytesToRead+1;
594	    do {
595		ch += *source++;
596		--tmpBytesToRead;
597		if (tmpBytesToRead) ch <<= 6;
598	    } while (tmpBytesToRead > 0);
599	}
600    In UTF-8 writing code, the switches on "bytesToWrite" are
601    similarly unrolled loops.
602
603   --------------------------------------------------------------------- */
604