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1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 ******************************************************************************
5 *
6 *   Copyright (C) 2003-2016, International Business Machines
7 *   Corporation and others.  All Rights Reserved.
8 *
9 ******************************************************************************
10 *   file name:  ucnv_ext.cpp
11 *   encoding:   UTF-8
12 *   tab size:   8 (not used)
13 *   indentation:4
14 *
15 *   created on: 2003jun13
16 *   created by: Markus W. Scherer
17 *
18 *   Conversion extensions
19 */
20 
21 #include "unicode/utypes.h"
22 
23 #if !UCONFIG_NO_CONVERSION && !UCONFIG_NO_LEGACY_CONVERSION
24 
25 #include "unicode/uset.h"
26 #include "unicode/ustring.h"
27 #include "ucnv_bld.h"
28 #include "ucnv_cnv.h"
29 #include "ucnv_ext.h"
30 #include "cmemory.h"
31 #include "uassert.h"
32 
33 /* to Unicode --------------------------------------------------------------- */
34 
35 /*
36  * @return lookup value for the byte, if found; else 0
37  */
38 static inline uint32_t
ucnv_extFindToU(const uint32_t * toUSection,int32_t length,uint8_t byte)39 ucnv_extFindToU(const uint32_t *toUSection, int32_t length, uint8_t byte) {
40     uint32_t word0, word;
41     int32_t i, start, limit;
42 
43     /* check the input byte against the lowest and highest section bytes */
44     start=(int32_t)UCNV_EXT_TO_U_GET_BYTE(toUSection[0]);
45     limit=(int32_t)UCNV_EXT_TO_U_GET_BYTE(toUSection[length-1]);
46     if(byte<start || limit<byte) {
47         return 0; /* the byte is out of range */
48     }
49 
50     if(length==((limit-start)+1)) {
51         /* direct access on a linear array */
52         return UCNV_EXT_TO_U_GET_VALUE(toUSection[byte-start]); /* could be 0 */
53     }
54 
55     /* word0 is suitable for <=toUSection[] comparison, word for <toUSection[] */
56     word0=UCNV_EXT_TO_U_MAKE_WORD(byte, 0);
57 
58     /*
59      * Shift byte once instead of each section word and add 0xffffff.
60      * We will compare the shifted/added byte (bbffffff) against
61      * section words which have byte values in the same bit position.
62      * If and only if byte bb < section byte ss then bbffffff<ssvvvvvv
63      * for all v=0..f
64      * so we need not mask off the lower 24 bits of each section word.
65      */
66     word=word0|UCNV_EXT_TO_U_VALUE_MASK;
67 
68     /* binary search */
69     start=0;
70     limit=length;
71     for(;;) {
72         i=limit-start;
73         if(i<=1) {
74             break; /* done */
75         }
76         /* start<limit-1 */
77 
78         if(i<=4) {
79             /* linear search for the last part */
80             if(word0<=toUSection[start]) {
81                 break;
82             }
83             if(++start<limit && word0<=toUSection[start]) {
84                 break;
85             }
86             if(++start<limit && word0<=toUSection[start]) {
87                 break;
88             }
89             /* always break at start==limit-1 */
90             ++start;
91             break;
92         }
93 
94         i=(start+limit)/2;
95         if(word<toUSection[i]) {
96             limit=i;
97         } else {
98             start=i;
99         }
100     }
101 
102     /* did we really find it? */
103     if(start<limit && byte==UCNV_EXT_TO_U_GET_BYTE(word=toUSection[start])) {
104         return UCNV_EXT_TO_U_GET_VALUE(word); /* never 0 */
105     } else {
106         return 0; /* not found */
107     }
108 }
109 
110 /*
111  * TRUE if not an SI/SO stateful converter,
112  * or if the match length fits with the current converter state
113  */
114 #define UCNV_EXT_TO_U_VERIFY_SISO_MATCH(sisoState, match) \
115     ((sisoState)<0 || ((sisoState)==0) == (match==1))
116 
117 /*
118  * this works like ucnv_extMatchFromU() except
119  * - the first character is in pre
120  * - no trie is used
121  * - the returned matchLength is not offset by 2
122  */
123 static int32_t
ucnv_extMatchToU(const int32_t * cx,int8_t sisoState,const char * pre,int32_t preLength,const char * src,int32_t srcLength,uint32_t * pMatchValue,UBool,UBool flush)124 ucnv_extMatchToU(const int32_t *cx, int8_t sisoState,
125                  const char *pre, int32_t preLength,
126                  const char *src, int32_t srcLength,
127                  uint32_t *pMatchValue,
128                  UBool /*useFallback*/, UBool flush) {
129     const uint32_t *toUTable, *toUSection;
130 
131     uint32_t value, matchValue;
132     int32_t i, j, idx, length, matchLength;
133     uint8_t b;
134 
135     if(cx==NULL || cx[UCNV_EXT_TO_U_LENGTH]<=0) {
136         return 0; /* no extension data, no match */
137     }
138 
139     /* initialize */
140     toUTable=UCNV_EXT_ARRAY(cx, UCNV_EXT_TO_U_INDEX, uint32_t);
141     idx=0;
142 
143     matchValue=0;
144     i=j=matchLength=0;
145 
146     if(sisoState==0) {
147         /* SBCS state of an SI/SO stateful converter, look at only exactly 1 byte */
148         if(preLength>1) {
149             return 0; /* no match of a DBCS sequence in SBCS mode */
150         } else if(preLength==1) {
151             srcLength=0;
152         } else /* preLength==0 */ {
153             if(srcLength>1) {
154                 srcLength=1;
155             }
156         }
157         flush=TRUE;
158     }
159 
160     /* we must not remember fallback matches when not using fallbacks */
161 
162     /* match input units until there is a full match or the input is consumed */
163     for(;;) {
164         /* go to the next section */
165         toUSection=toUTable+idx;
166 
167         /* read first pair of the section */
168         value=*toUSection++;
169         length=UCNV_EXT_TO_U_GET_BYTE(value);
170         value=UCNV_EXT_TO_U_GET_VALUE(value);
171         if( value!=0 &&
172             (UCNV_EXT_TO_U_IS_ROUNDTRIP(value) ||
173              TO_U_USE_FALLBACK(useFallback)) &&
174             UCNV_EXT_TO_U_VERIFY_SISO_MATCH(sisoState, i+j)
175         ) {
176             /* remember longest match so far */
177             matchValue=value;
178             matchLength=i+j;
179         }
180 
181         /* match pre[] then src[] */
182         if(i<preLength) {
183             b=(uint8_t)pre[i++];
184         } else if(j<srcLength) {
185             b=(uint8_t)src[j++];
186         } else {
187             /* all input consumed, partial match */
188             if(flush || (length=(i+j))>UCNV_EXT_MAX_BYTES) {
189                 /*
190                  * end of the entire input stream, stop with the longest match so far
191                  * or: partial match must not be longer than UCNV_EXT_MAX_BYTES
192                  * because it must fit into state buffers
193                  */
194                 break;
195             } else {
196                 /* continue with more input next time */
197                 return -length;
198             }
199         }
200 
201         /* search for the current UChar */
202         value=ucnv_extFindToU(toUSection, length, b);
203         if(value==0) {
204             /* no match here, stop with the longest match so far */
205             break;
206         } else {
207             if(UCNV_EXT_TO_U_IS_PARTIAL(value)) {
208                 /* partial match, continue */
209                 idx=(int32_t)UCNV_EXT_TO_U_GET_PARTIAL_INDEX(value);
210             } else {
211                 if( (UCNV_EXT_TO_U_IS_ROUNDTRIP(value) ||
212                      TO_U_USE_FALLBACK(useFallback)) &&
213                     UCNV_EXT_TO_U_VERIFY_SISO_MATCH(sisoState, i+j)
214                 ) {
215                     /* full match, stop with result */
216                     matchValue=value;
217                     matchLength=i+j;
218                 } else {
219                     /* full match on fallback not taken, stop with the longest match so far */
220                 }
221                 break;
222             }
223         }
224     }
225 
226     if(matchLength==0) {
227         /* no match at all */
228         return 0;
229     }
230 
231     /* return result */
232     *pMatchValue=UCNV_EXT_TO_U_MASK_ROUNDTRIP(matchValue);
233     return matchLength;
234 }
235 
236 static inline void
ucnv_extWriteToU(UConverter * cnv,const int32_t * cx,uint32_t value,UChar ** target,const UChar * targetLimit,int32_t ** offsets,int32_t srcIndex,UErrorCode * pErrorCode)237 ucnv_extWriteToU(UConverter *cnv, const int32_t *cx,
238                  uint32_t value,
239                  UChar **target, const UChar *targetLimit,
240                  int32_t **offsets, int32_t srcIndex,
241                  UErrorCode *pErrorCode) {
242     /* output the result */
243     if(UCNV_EXT_TO_U_IS_CODE_POINT(value)) {
244         /* output a single code point */
245         ucnv_toUWriteCodePoint(
246             cnv, UCNV_EXT_TO_U_GET_CODE_POINT(value),
247             target, targetLimit,
248             offsets, srcIndex,
249             pErrorCode);
250     } else {
251         /* output a string - with correct data we have resultLength>0 */
252         ucnv_toUWriteUChars(
253             cnv,
254             UCNV_EXT_ARRAY(cx, UCNV_EXT_TO_U_UCHARS_INDEX, UChar)+
255                 UCNV_EXT_TO_U_GET_INDEX(value),
256             UCNV_EXT_TO_U_GET_LENGTH(value),
257             target, targetLimit,
258             offsets, srcIndex,
259             pErrorCode);
260     }
261 }
262 
263 /*
264  * get the SI/SO toU state (state 0 is for SBCS, 1 for DBCS),
265  * or 1 for DBCS-only,
266  * or -1 if the converter is not SI/SO stateful
267  *
268  * Note: For SI/SO stateful converters getting here,
269  * cnv->mode==0 is equivalent to firstLength==1.
270  */
271 #define UCNV_SISO_STATE(cnv) \
272     ((cnv)->sharedData->mbcs.outputType==MBCS_OUTPUT_2_SISO ? (int8_t)(cnv)->mode : \
273      (cnv)->sharedData->mbcs.outputType==MBCS_OUTPUT_DBCS_ONLY ? 1 : -1)
274 
275 /*
276  * target<targetLimit; set error code for overflow
277  */
278 U_CFUNC UBool
ucnv_extInitialMatchToU(UConverter * cnv,const int32_t * cx,int32_t firstLength,const char ** src,const char * srcLimit,UChar ** target,const UChar * targetLimit,int32_t ** offsets,int32_t srcIndex,UBool flush,UErrorCode * pErrorCode)279 ucnv_extInitialMatchToU(UConverter *cnv, const int32_t *cx,
280                         int32_t firstLength,
281                         const char **src, const char *srcLimit,
282                         UChar **target, const UChar *targetLimit,
283                         int32_t **offsets, int32_t srcIndex,
284                         UBool flush,
285                         UErrorCode *pErrorCode) {
286     uint32_t value = 0;  /* initialize output-only param to 0 to silence gcc */
287     int32_t match;
288 
289     /* try to match */
290     match=ucnv_extMatchToU(cx, (int8_t)UCNV_SISO_STATE(cnv),
291                            (const char *)cnv->toUBytes, firstLength,
292                            *src, (int32_t)(srcLimit-*src),
293                            &value,
294                            cnv->useFallback, flush);
295     if(match>0) {
296         /* advance src pointer for the consumed input */
297         *src+=match-firstLength;
298 
299         /* write result to target */
300         ucnv_extWriteToU(cnv, cx,
301                          value,
302                          target, targetLimit,
303                          offsets, srcIndex,
304                          pErrorCode);
305         return TRUE;
306     } else if(match<0) {
307         /* save state for partial match */
308         const char *s;
309         int32_t j;
310 
311         /* copy the first code point */
312         s=(const char *)cnv->toUBytes;
313         cnv->preToUFirstLength=(int8_t)firstLength;
314         for(j=0; j<firstLength; ++j) {
315             cnv->preToU[j]=*s++;
316         }
317 
318         /* now copy the newly consumed input */
319         s=*src;
320         match=-match;
321         for(; j<match; ++j) {
322             cnv->preToU[j]=*s++;
323         }
324         *src=s; /* same as *src=srcLimit; because we reached the end of input */
325         cnv->preToULength=(int8_t)match;
326         return TRUE;
327     } else /* match==0 no match */ {
328         return FALSE;
329     }
330 }
331 
332 U_CFUNC UChar32
ucnv_extSimpleMatchToU(const int32_t * cx,const char * source,int32_t length,UBool useFallback)333 ucnv_extSimpleMatchToU(const int32_t *cx,
334                        const char *source, int32_t length,
335                        UBool useFallback) {
336     uint32_t value = 0;  /* initialize output-only param to 0 to silence gcc */
337     int32_t match;
338 
339     if(length<=0) {
340         return 0xffff;
341     }
342 
343     /* try to match */
344     match=ucnv_extMatchToU(cx, -1,
345                            source, length,
346                            NULL, 0,
347                            &value,
348                            useFallback, TRUE);
349     if(match==length) {
350         /* write result for simple, single-character conversion */
351         if(UCNV_EXT_TO_U_IS_CODE_POINT(value)) {
352             return UCNV_EXT_TO_U_GET_CODE_POINT(value);
353         }
354     }
355 
356     /*
357      * return no match because
358      * - match>0 && value points to string: simple conversion cannot handle multiple code points
359      * - match>0 && match!=length: not all input consumed, forbidden for this function
360      * - match==0: no match found in the first place
361      * - match<0: partial match, not supported for simple conversion (and flush==TRUE)
362      */
363     return 0xfffe;
364 }
365 
366 /*
367  * continue partial match with new input
368  * never called for simple, single-character conversion
369  */
370 U_CFUNC void
ucnv_extContinueMatchToU(UConverter * cnv,UConverterToUnicodeArgs * pArgs,int32_t srcIndex,UErrorCode * pErrorCode)371 ucnv_extContinueMatchToU(UConverter *cnv,
372                          UConverterToUnicodeArgs *pArgs, int32_t srcIndex,
373                          UErrorCode *pErrorCode) {
374     uint32_t value = 0;  /* initialize output-only param to 0 to silence gcc */
375     int32_t match, length;
376 
377     match=ucnv_extMatchToU(cnv->sharedData->mbcs.extIndexes, (int8_t)UCNV_SISO_STATE(cnv),
378                            cnv->preToU, cnv->preToULength,
379                            pArgs->source, (int32_t)(pArgs->sourceLimit-pArgs->source),
380                            &value,
381                            cnv->useFallback, pArgs->flush);
382     if(match>0) {
383         if(match>=cnv->preToULength) {
384             /* advance src pointer for the consumed input */
385             pArgs->source+=match-cnv->preToULength;
386             cnv->preToULength=0;
387         } else {
388             /* the match did not use all of preToU[] - keep the rest for replay */
389             length=cnv->preToULength-match;
390             uprv_memmove(cnv->preToU, cnv->preToU+match, length);
391             cnv->preToULength=(int8_t)-length;
392         }
393 
394         /* write result */
395         ucnv_extWriteToU(cnv, cnv->sharedData->mbcs.extIndexes,
396                          value,
397                          &pArgs->target, pArgs->targetLimit,
398                          &pArgs->offsets, srcIndex,
399                          pErrorCode);
400     } else if(match<0) {
401         /* save state for partial match */
402         const char *s;
403         int32_t j;
404 
405         /* just _append_ the newly consumed input to preToU[] */
406         s=pArgs->source;
407         match=-match;
408         for(j=cnv->preToULength; j<match; ++j) {
409             cnv->preToU[j]=*s++;
410         }
411         pArgs->source=s; /* same as *src=srcLimit; because we reached the end of input */
412         cnv->preToULength=(int8_t)match;
413     } else /* match==0 */ {
414         /*
415          * no match
416          *
417          * We need to split the previous input into two parts:
418          *
419          * 1. The first codepage character is unmappable - that's how we got into
420          *    trying the extension data in the first place.
421          *    We need to move it from the preToU buffer
422          *    to the error buffer, set an error code,
423          *    and prepare the rest of the previous input for 2.
424          *
425          * 2. The rest of the previous input must be converted once we
426          *    come back from the callback for the first character.
427          *    At that time, we have to try again from scratch to convert
428          *    these input characters.
429          *    The replay will be handled by the ucnv.c conversion code.
430          */
431 
432         /* move the first codepage character to the error field */
433         uprv_memcpy(cnv->toUBytes, cnv->preToU, cnv->preToUFirstLength);
434         cnv->toULength=cnv->preToUFirstLength;
435 
436         /* move the rest up inside the buffer */
437         length=cnv->preToULength-cnv->preToUFirstLength;
438         if(length>0) {
439             uprv_memmove(cnv->preToU, cnv->preToU+cnv->preToUFirstLength, length);
440         }
441 
442         /* mark preToU for replay */
443         cnv->preToULength=(int8_t)-length;
444 
445         /* set the error code for unassigned */
446         *pErrorCode=U_INVALID_CHAR_FOUND;
447     }
448 }
449 
450 /* from Unicode ------------------------------------------------------------- */
451 
452 // Use roundtrips, "good one-way" mappings, and some normal fallbacks.
453 static inline UBool
extFromUUseMapping(UBool useFallback,uint32_t value,UChar32 firstCP)454 extFromUUseMapping(UBool useFallback, uint32_t value, UChar32 firstCP) {
455     return
456         ((value&UCNV_EXT_FROM_U_STATUS_MASK)!=0 ||
457             FROM_U_USE_FALLBACK(useFallback, firstCP)) &&
458         (value&UCNV_EXT_FROM_U_RESERVED_MASK)==0;
459 }
460 
461 /*
462  * @return index of the UChar, if found; else <0
463  */
464 static inline int32_t
ucnv_extFindFromU(const UChar * fromUSection,int32_t length,UChar u)465 ucnv_extFindFromU(const UChar *fromUSection, int32_t length, UChar u) {
466     int32_t i, start, limit;
467 
468     /* binary search */
469     start=0;
470     limit=length;
471     for(;;) {
472         i=limit-start;
473         if(i<=1) {
474             break; /* done */
475         }
476         /* start<limit-1 */
477 
478         if(i<=4) {
479             /* linear search for the last part */
480             if(u<=fromUSection[start]) {
481                 break;
482             }
483             if(++start<limit && u<=fromUSection[start]) {
484                 break;
485             }
486             if(++start<limit && u<=fromUSection[start]) {
487                 break;
488             }
489             /* always break at start==limit-1 */
490             ++start;
491             break;
492         }
493 
494         i=(start+limit)/2;
495         if(u<fromUSection[i]) {
496             limit=i;
497         } else {
498             start=i;
499         }
500     }
501 
502     /* did we really find it? */
503     if(start<limit && u==fromUSection[start]) {
504         return start;
505     } else {
506         return -1; /* not found */
507     }
508 }
509 
510 /*
511  * @param cx pointer to extension data; if NULL, returns 0
512  * @param firstCP the first code point before all the other UChars
513  * @param pre UChars that must match; !initialMatch: partial match with them
514  * @param preLength length of pre, >=0
515  * @param src UChars that can be used to complete a match
516  * @param srcLength length of src, >=0
517  * @param pMatchValue [out] output result value for the match from the data structure
518  * @param useFallback "use fallback" flag, usually from cnv->useFallback
519  * @param flush TRUE if the end of the input stream is reached
520  * @return >1: matched, return value=total match length (number of input units matched)
521  *          1: matched, no mapping but request for <subchar1>
522  *             (only for the first code point)
523  *          0: no match
524  *         <0: partial match, return value=negative total match length
525  *             (partial matches are never returned for flush==TRUE)
526  *             (partial matches are never returned as being longer than UCNV_EXT_MAX_UCHARS)
527  *         the matchLength is 2 if only firstCP matched, and >2 if firstCP and
528  *         further code units matched
529  */
530 static int32_t
ucnv_extMatchFromU(const int32_t * cx,UChar32 firstCP,const UChar * pre,int32_t preLength,const UChar * src,int32_t srcLength,uint32_t * pMatchValue,UBool useFallback,UBool flush)531 ucnv_extMatchFromU(const int32_t *cx,
532                    UChar32 firstCP,
533                    const UChar *pre, int32_t preLength,
534                    const UChar *src, int32_t srcLength,
535                    uint32_t *pMatchValue,
536                    UBool useFallback, UBool flush) {
537     const uint16_t *stage12, *stage3;
538     const uint32_t *stage3b;
539 
540     const UChar *fromUTableUChars, *fromUSectionUChars;
541     const uint32_t *fromUTableValues, *fromUSectionValues;
542 
543     uint32_t value, matchValue;
544     int32_t i, j, idx, length, matchLength;
545     UChar c;
546 
547     if(cx==NULL) {
548         return 0; /* no extension data, no match */
549     }
550 
551     /* trie lookup of firstCP */
552     idx=firstCP>>10; /* stage 1 index */
553     if(idx>=cx[UCNV_EXT_FROM_U_STAGE_1_LENGTH]) {
554         return 0; /* the first code point is outside the trie */
555     }
556 
557     stage12=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_12_INDEX, uint16_t);
558     stage3=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_3_INDEX, uint16_t);
559     idx=UCNV_EXT_FROM_U(stage12, stage3, idx, firstCP);
560 
561     stage3b=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_3B_INDEX, uint32_t);
562     value=stage3b[idx];
563     if(value==0) {
564         return 0;
565     }
566 
567     /*
568      * Tests for (value&UCNV_EXT_FROM_U_RESERVED_MASK)==0:
569      * Do not interpret values with reserved bits used, for forward compatibility,
570      * and do not even remember intermediate results with reserved bits used.
571      */
572 
573     if(UCNV_EXT_TO_U_IS_PARTIAL(value)) {
574         /* partial match, enter the loop below */
575         idx=(int32_t)UCNV_EXT_FROM_U_GET_PARTIAL_INDEX(value);
576 
577         /* initialize */
578         fromUTableUChars=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_UCHARS_INDEX, UChar);
579         fromUTableValues=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_VALUES_INDEX, uint32_t);
580 
581         matchValue=0;
582         i=j=matchLength=0;
583 
584         /* we must not remember fallback matches when not using fallbacks */
585 
586         /* match input units until there is a full match or the input is consumed */
587         for(;;) {
588             /* go to the next section */
589             fromUSectionUChars=fromUTableUChars+idx;
590             fromUSectionValues=fromUTableValues+idx;
591 
592             /* read first pair of the section */
593             length=*fromUSectionUChars++;
594             value=*fromUSectionValues++;
595             if(value!=0 && extFromUUseMapping(useFallback, value, firstCP)) {
596                 /* remember longest match so far */
597                 matchValue=value;
598                 matchLength=2+i+j;
599             }
600 
601             /* match pre[] then src[] */
602             if(i<preLength) {
603                 c=pre[i++];
604             } else if(j<srcLength) {
605                 c=src[j++];
606             } else {
607                 /* all input consumed, partial match */
608                 if(flush || (length=(i+j))>UCNV_EXT_MAX_UCHARS) {
609                     /*
610                      * end of the entire input stream, stop with the longest match so far
611                      * or: partial match must not be longer than UCNV_EXT_MAX_UCHARS
612                      * because it must fit into state buffers
613                      */
614                     break;
615                 } else {
616                     /* continue with more input next time */
617                     return -(2+length);
618                 }
619             }
620 
621             /* search for the current UChar */
622             idx=ucnv_extFindFromU(fromUSectionUChars, length, c);
623             if(idx<0) {
624                 /* no match here, stop with the longest match so far */
625                 break;
626             } else {
627                 value=fromUSectionValues[idx];
628                 if(UCNV_EXT_FROM_U_IS_PARTIAL(value)) {
629                     /* partial match, continue */
630                     idx=(int32_t)UCNV_EXT_FROM_U_GET_PARTIAL_INDEX(value);
631                 } else {
632                     if(extFromUUseMapping(useFallback, value, firstCP)) {
633                         /* full match, stop with result */
634                         matchValue=value;
635                         matchLength=2+i+j;
636                     } else {
637                         /* full match on fallback not taken, stop with the longest match so far */
638                     }
639                     break;
640                 }
641             }
642         }
643 
644         if(matchLength==0) {
645             /* no match at all */
646             return 0;
647         }
648     } else /* result from firstCP trie lookup */ {
649         if(extFromUUseMapping(useFallback, value, firstCP)) {
650             /* full match, stop with result */
651             matchValue=value;
652             matchLength=2;
653         } else {
654             /* fallback not taken */
655             return 0;
656         }
657     }
658 
659     /* return result */
660     if(matchValue==UCNV_EXT_FROM_U_SUBCHAR1) {
661         return 1; /* assert matchLength==2 */
662     }
663 
664     *pMatchValue=matchValue;
665     return matchLength;
666 }
667 
668 /*
669  * @param value fromUnicode mapping table value; ignores roundtrip and reserved bits
670  */
671 static inline void
ucnv_extWriteFromU(UConverter * cnv,const int32_t * cx,uint32_t value,char ** target,const char * targetLimit,int32_t ** offsets,int32_t srcIndex,UErrorCode * pErrorCode)672 ucnv_extWriteFromU(UConverter *cnv, const int32_t *cx,
673                    uint32_t value,
674                    char **target, const char *targetLimit,
675                    int32_t **offsets, int32_t srcIndex,
676                    UErrorCode *pErrorCode) {
677     uint8_t buffer[1+UCNV_EXT_MAX_BYTES];
678     const uint8_t *result;
679     int32_t length, prevLength;
680 
681     length=UCNV_EXT_FROM_U_GET_LENGTH(value);
682     value=(uint32_t)UCNV_EXT_FROM_U_GET_DATA(value);
683 
684     /* output the result */
685     if(length<=UCNV_EXT_FROM_U_MAX_DIRECT_LENGTH) {
686         /*
687          * Generate a byte array and then write it below.
688          * This is not the fastest possible way, but it should be ok for
689          * extension mappings, and it is much simpler.
690          * Offset and overflow handling are only done once this way.
691          */
692         uint8_t *p=buffer+1; /* reserve buffer[0] for shiftByte below */
693         switch(length) {
694         case 3:
695             *p++=(uint8_t)(value>>16);
696             U_FALLTHROUGH;
697         case 2:
698             *p++=(uint8_t)(value>>8);
699             U_FALLTHROUGH;
700         case 1:
701             *p++=(uint8_t)value;
702             U_FALLTHROUGH;
703         default:
704             break; /* will never occur */
705         }
706         result=buffer+1;
707     } else {
708         result=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_BYTES_INDEX, uint8_t)+value;
709     }
710 
711     /* with correct data we have length>0 */
712 
713     if((prevLength=cnv->fromUnicodeStatus)!=0) {
714         /* handle SI/SO stateful output */
715         uint8_t shiftByte;
716 
717         if(prevLength>1 && length==1) {
718             /* change from double-byte mode to single-byte */
719             shiftByte=(uint8_t)UCNV_SI;
720             cnv->fromUnicodeStatus=1;
721         } else if(prevLength==1 && length>1) {
722             /* change from single-byte mode to double-byte */
723             shiftByte=(uint8_t)UCNV_SO;
724             cnv->fromUnicodeStatus=2;
725         } else {
726             shiftByte=0;
727         }
728 
729         if(shiftByte!=0) {
730             /* prepend the shift byte to the result bytes */
731             buffer[0]=shiftByte;
732             if(result!=buffer+1) {
733                 uprv_memcpy(buffer+1, result, length);
734             }
735             result=buffer;
736             ++length;
737         }
738     }
739 
740     ucnv_fromUWriteBytes(cnv, (const char *)result, length,
741                          target, targetLimit,
742                          offsets, srcIndex,
743                          pErrorCode);
744 }
745 
746 /*
747  * target<targetLimit; set error code for overflow
748  */
749 U_CFUNC UBool
ucnv_extInitialMatchFromU(UConverter * cnv,const int32_t * cx,UChar32 cp,const UChar ** src,const UChar * srcLimit,char ** target,const char * targetLimit,int32_t ** offsets,int32_t srcIndex,UBool flush,UErrorCode * pErrorCode)750 ucnv_extInitialMatchFromU(UConverter *cnv, const int32_t *cx,
751                           UChar32 cp,
752                           const UChar **src, const UChar *srcLimit,
753                           char **target, const char *targetLimit,
754                           int32_t **offsets, int32_t srcIndex,
755                           UBool flush,
756                           UErrorCode *pErrorCode) {
757     uint32_t value = 0;  /* initialize output-only param to 0 to silence gcc */
758     int32_t match;
759 
760     /* try to match */
761     match=ucnv_extMatchFromU(cx, cp,
762                              NULL, 0,
763                              *src, (int32_t)(srcLimit-*src),
764                              &value,
765                              cnv->useFallback, flush);
766 
767     /* reject a match if the result is a single byte for DBCS-only */
768     if( match>=2 &&
769         !(UCNV_EXT_FROM_U_GET_LENGTH(value)==1 &&
770           cnv->sharedData->mbcs.outputType==MBCS_OUTPUT_DBCS_ONLY)
771     ) {
772         /* advance src pointer for the consumed input */
773         *src+=match-2; /* remove 2 for the initial code point */
774 
775         /* write result to target */
776         ucnv_extWriteFromU(cnv, cx,
777                            value,
778                            target, targetLimit,
779                            offsets, srcIndex,
780                            pErrorCode);
781         return TRUE;
782     } else if(match<0) {
783         /* save state for partial match */
784         const UChar *s;
785         int32_t j;
786 
787         /* copy the first code point */
788         cnv->preFromUFirstCP=cp;
789 
790         /* now copy the newly consumed input */
791         s=*src;
792         match=-match-2; /* remove 2 for the initial code point */
793         for(j=0; j<match; ++j) {
794             cnv->preFromU[j]=*s++;
795         }
796         *src=s; /* same as *src=srcLimit; because we reached the end of input */
797         cnv->preFromULength=(int8_t)match;
798         return TRUE;
799     } else if(match==1) {
800         /* matched, no mapping but request for <subchar1> */
801         cnv->useSubChar1=TRUE;
802         return FALSE;
803     } else /* match==0 no match */ {
804         return FALSE;
805     }
806 }
807 
808 /*
809  * Used by ISO 2022 implementation.
810  * @return number of bytes in *pValue; negative number if fallback; 0 for no mapping
811  */
812 U_CFUNC int32_t
ucnv_extSimpleMatchFromU(const int32_t * cx,UChar32 cp,uint32_t * pValue,UBool useFallback)813 ucnv_extSimpleMatchFromU(const int32_t *cx,
814                          UChar32 cp, uint32_t *pValue,
815                          UBool useFallback) {
816     uint32_t value;
817     int32_t match;
818 
819     /* try to match */
820     match=ucnv_extMatchFromU(cx,
821                              cp,
822                              NULL, 0,
823                              NULL, 0,
824                              &value,
825                              useFallback, TRUE);
826     if(match>=2) {
827         /* write result for simple, single-character conversion */
828         int32_t length;
829         int isRoundtrip;
830 
831         isRoundtrip=UCNV_EXT_FROM_U_IS_ROUNDTRIP(value);
832         length=UCNV_EXT_FROM_U_GET_LENGTH(value);
833         value=(uint32_t)UCNV_EXT_FROM_U_GET_DATA(value);
834 
835         if(length<=UCNV_EXT_FROM_U_MAX_DIRECT_LENGTH) {
836             *pValue=value;
837             return isRoundtrip ? length : -length;
838 #if 0 /* not currently used */
839         } else if(length==4) {
840             /* de-serialize a 4-byte result */
841             const uint8_t *result=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_BYTES_INDEX, uint8_t)+value;
842             *pValue=
843                 ((uint32_t)result[0]<<24)|
844                 ((uint32_t)result[1]<<16)|
845                 ((uint32_t)result[2]<<8)|
846                 result[3];
847             return isRoundtrip ? 4 : -4;
848 #endif
849         }
850     }
851 
852     /*
853      * return no match because
854      * - match>1 && resultLength>4: result too long for simple conversion
855      * - match==1: no match found, <subchar1> preferred
856      * - match==0: no match found in the first place
857      * - match<0: partial match, not supported for simple conversion (and flush==TRUE)
858      */
859     return 0;
860 }
861 
862 /*
863  * continue partial match with new input, requires cnv->preFromUFirstCP>=0
864  * never called for simple, single-character conversion
865  */
866 U_CFUNC void
ucnv_extContinueMatchFromU(UConverter * cnv,UConverterFromUnicodeArgs * pArgs,int32_t srcIndex,UErrorCode * pErrorCode)867 ucnv_extContinueMatchFromU(UConverter *cnv,
868                            UConverterFromUnicodeArgs *pArgs, int32_t srcIndex,
869                            UErrorCode *pErrorCode) {
870     uint32_t value = 0;  /* initialize output-only param to 0 to silence gcc */
871     int32_t match;
872 
873     match=ucnv_extMatchFromU(cnv->sharedData->mbcs.extIndexes,
874                              cnv->preFromUFirstCP,
875                              cnv->preFromU, cnv->preFromULength,
876                              pArgs->source, (int32_t)(pArgs->sourceLimit-pArgs->source),
877                              &value,
878                              cnv->useFallback, pArgs->flush);
879     if(match>=2) {
880         match-=2; /* remove 2 for the initial code point */
881 
882         if(match>=cnv->preFromULength) {
883             /* advance src pointer for the consumed input */
884             pArgs->source+=match-cnv->preFromULength;
885             cnv->preFromULength=0;
886         } else {
887             /* the match did not use all of preFromU[] - keep the rest for replay */
888             int32_t length=cnv->preFromULength-match;
889             u_memmove(cnv->preFromU, cnv->preFromU+match, length);
890             cnv->preFromULength=(int8_t)-length;
891         }
892 
893         /* finish the partial match */
894         cnv->preFromUFirstCP=U_SENTINEL;
895 
896         /* write result */
897         ucnv_extWriteFromU(cnv, cnv->sharedData->mbcs.extIndexes,
898                            value,
899                            &pArgs->target, pArgs->targetLimit,
900                            &pArgs->offsets, srcIndex,
901                            pErrorCode);
902     } else if(match<0) {
903         /* save state for partial match */
904         const UChar *s;
905         int32_t j;
906 
907         /* just _append_ the newly consumed input to preFromU[] */
908         s=pArgs->source;
909         match=-match-2; /* remove 2 for the initial code point */
910         for(j=cnv->preFromULength; j<match; ++j) {
911             U_ASSERT(j>=0);
912             cnv->preFromU[j]=*s++;
913         }
914         pArgs->source=s; /* same as *src=srcLimit; because we reached the end of input */
915         cnv->preFromULength=(int8_t)match;
916     } else /* match==0 or 1 */ {
917         /*
918          * no match
919          *
920          * We need to split the previous input into two parts:
921          *
922          * 1. The first code point is unmappable - that's how we got into
923          *    trying the extension data in the first place.
924          *    We need to move it from the preFromU buffer
925          *    to the error buffer, set an error code,
926          *    and prepare the rest of the previous input for 2.
927          *
928          * 2. The rest of the previous input must be converted once we
929          *    come back from the callback for the first code point.
930          *    At that time, we have to try again from scratch to convert
931          *    these input characters.
932          *    The replay will be handled by the ucnv.c conversion code.
933          */
934 
935         if(match==1) {
936             /* matched, no mapping but request for <subchar1> */
937             cnv->useSubChar1=TRUE;
938         }
939 
940         /* move the first code point to the error field */
941         cnv->fromUChar32=cnv->preFromUFirstCP;
942         cnv->preFromUFirstCP=U_SENTINEL;
943 
944         /* mark preFromU for replay */
945         cnv->preFromULength=-cnv->preFromULength;
946 
947         /* set the error code for unassigned */
948         *pErrorCode=U_INVALID_CHAR_FOUND;
949     }
950 }
951 
952 static UBool
extSetUseMapping(UConverterUnicodeSet which,int32_t minLength,uint32_t value)953 extSetUseMapping(UConverterUnicodeSet which, int32_t minLength, uint32_t value) {
954     if(which==UCNV_ROUNDTRIP_SET) {
955         // Add only code points for which the roundtrip flag is set.
956         // Do not add any fallbacks, even if ucnv_fromUnicode() would use them
957         // (fallbacks from PUA). See the API docs for ucnv_getUnicodeSet().
958         //
959         // By analogy, also do not add "good one-way" mappings.
960         //
961         // Do not add entries with reserved bits set.
962         if(((value&(UCNV_EXT_FROM_U_ROUNDTRIP_FLAG|UCNV_EXT_FROM_U_RESERVED_MASK))!=
963                 UCNV_EXT_FROM_U_ROUNDTRIP_FLAG)) {
964             return FALSE;
965         }
966     } else /* UCNV_ROUNDTRIP_AND_FALLBACK_SET */ {
967         // Do not add entries with reserved bits set.
968         if((value&UCNV_EXT_FROM_U_RESERVED_MASK)!=0) {
969             return FALSE;
970         }
971     }
972     // Do not add <subchar1> entries or other (future?) pseudo-entries
973     // with an output length of 0.
974     return UCNV_EXT_FROM_U_GET_LENGTH(value)>=minLength;
975 }
976 
977 static void
ucnv_extGetUnicodeSetString(const UConverterSharedData * sharedData,const int32_t * cx,const USetAdder * sa,UConverterUnicodeSet which,int32_t minLength,UChar32 firstCP,UChar s[UCNV_EXT_MAX_UCHARS],int32_t length,int32_t sectionIndex,UErrorCode * pErrorCode)978 ucnv_extGetUnicodeSetString(const UConverterSharedData *sharedData,
979                             const int32_t *cx,
980                             const USetAdder *sa,
981                             UConverterUnicodeSet which,
982                             int32_t minLength,
983                             UChar32 firstCP,
984                             UChar s[UCNV_EXT_MAX_UCHARS], int32_t length,
985                             int32_t sectionIndex,
986                             UErrorCode *pErrorCode) {
987     const UChar *fromUSectionUChars;
988     const uint32_t *fromUSectionValues;
989 
990     uint32_t value;
991     int32_t i, count;
992 
993     fromUSectionUChars=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_UCHARS_INDEX, UChar)+sectionIndex;
994     fromUSectionValues=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_VALUES_INDEX, uint32_t)+sectionIndex;
995 
996     /* read first pair of the section */
997     count=*fromUSectionUChars++;
998     value=*fromUSectionValues++;
999 
1000     if(extSetUseMapping(which, minLength, value)) {
1001         if(length==U16_LENGTH(firstCP)) {
1002             /* add the initial code point */
1003             sa->add(sa->set, firstCP);
1004         } else {
1005             /* add the string so far */
1006             sa->addString(sa->set, s, length);
1007         }
1008     }
1009 
1010     for(i=0; i<count; ++i) {
1011         /* append this code unit and recurse or add the string */
1012         s[length]=fromUSectionUChars[i];
1013         value=fromUSectionValues[i];
1014 
1015         if(value==0) {
1016             /* no mapping, do nothing */
1017         } else if(UCNV_EXT_FROM_U_IS_PARTIAL(value)) {
1018             ucnv_extGetUnicodeSetString(
1019                 sharedData, cx, sa, which, minLength,
1020                 firstCP, s, length+1,
1021                 (int32_t)UCNV_EXT_FROM_U_GET_PARTIAL_INDEX(value),
1022                 pErrorCode);
1023         } else if(extSetUseMapping(which, minLength, value)) {
1024             sa->addString(sa->set, s, length+1);
1025         }
1026     }
1027 }
1028 
1029 U_CFUNC void
ucnv_extGetUnicodeSet(const UConverterSharedData * sharedData,const USetAdder * sa,UConverterUnicodeSet which,UConverterSetFilter filter,UErrorCode * pErrorCode)1030 ucnv_extGetUnicodeSet(const UConverterSharedData *sharedData,
1031                       const USetAdder *sa,
1032                       UConverterUnicodeSet which,
1033                       UConverterSetFilter filter,
1034                       UErrorCode *pErrorCode) {
1035     const int32_t *cx;
1036     const uint16_t *stage12, *stage3, *ps2, *ps3;
1037     const uint32_t *stage3b;
1038 
1039     uint32_t value;
1040     int32_t st1, stage1Length, st2, st3, minLength;
1041 
1042     UChar s[UCNV_EXT_MAX_UCHARS];
1043     UChar32 c;
1044     int32_t length;
1045 
1046     cx=sharedData->mbcs.extIndexes;
1047     if(cx==NULL) {
1048         return;
1049     }
1050 
1051     stage12=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_12_INDEX, uint16_t);
1052     stage3=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_3_INDEX, uint16_t);
1053     stage3b=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_3B_INDEX, uint32_t);
1054 
1055     stage1Length=cx[UCNV_EXT_FROM_U_STAGE_1_LENGTH];
1056 
1057     /* enumerate the from-Unicode trie table */
1058     c=0; /* keep track of the current code point while enumerating */
1059 
1060     if(filter==UCNV_SET_FILTER_2022_CN) {
1061         minLength=3;
1062     } else if( sharedData->mbcs.outputType==MBCS_OUTPUT_DBCS_ONLY ||
1063                filter!=UCNV_SET_FILTER_NONE
1064     ) {
1065         /* DBCS-only, ignore single-byte results */
1066         minLength=2;
1067     } else {
1068         minLength=1;
1069     }
1070 
1071     /*
1072      * the trie enumeration is almost the same as
1073      * in MBCSGetUnicodeSet() for MBCS_OUTPUT_1
1074      */
1075     for(st1=0; st1<stage1Length; ++st1) {
1076         st2=stage12[st1];
1077         if(st2>stage1Length) {
1078             ps2=stage12+st2;
1079             for(st2=0; st2<64; ++st2) {
1080                 if((st3=(int32_t)ps2[st2]<<UCNV_EXT_STAGE_2_LEFT_SHIFT)!=0) {
1081                     /* read the stage 3 block */
1082                     ps3=stage3+st3;
1083 
1084                     do {
1085                         value=stage3b[*ps3++];
1086                         if(value==0) {
1087                             /* no mapping, do nothing */
1088                         } else if(UCNV_EXT_FROM_U_IS_PARTIAL(value)) {
1089                             // Recurse for partial results.
1090                             length=0;
1091                             U16_APPEND_UNSAFE(s, length, c);
1092                             ucnv_extGetUnicodeSetString(
1093                                 sharedData, cx, sa, which, minLength,
1094                                 c, s, length,
1095                                 (int32_t)UCNV_EXT_FROM_U_GET_PARTIAL_INDEX(value),
1096                                 pErrorCode);
1097                         } else if(extSetUseMapping(which, minLength, value)) {
1098                             switch(filter) {
1099                             case UCNV_SET_FILTER_2022_CN:
1100                                 if(!(UCNV_EXT_FROM_U_GET_LENGTH(value)==3 && UCNV_EXT_FROM_U_GET_DATA(value)<=0x82ffff)) {
1101                                     continue;
1102                                 }
1103                                 break;
1104                             case UCNV_SET_FILTER_SJIS:
1105                                 if(!(UCNV_EXT_FROM_U_GET_LENGTH(value)==2 && (value=UCNV_EXT_FROM_U_GET_DATA(value))>=0x8140 && value<=0xeffc)) {
1106                                     continue;
1107                                 }
1108                                 break;
1109                             case UCNV_SET_FILTER_GR94DBCS:
1110                                 if(!(UCNV_EXT_FROM_U_GET_LENGTH(value)==2 &&
1111                                      (uint16_t)((value=UCNV_EXT_FROM_U_GET_DATA(value))-0xa1a1)<=(0xfefe - 0xa1a1) &&
1112                                      (uint8_t)(value-0xa1)<=(0xfe - 0xa1))) {
1113                                     continue;
1114                                 }
1115                                 break;
1116                             case UCNV_SET_FILTER_HZ:
1117                                 if(!(UCNV_EXT_FROM_U_GET_LENGTH(value)==2 &&
1118                                      (uint16_t)((value=UCNV_EXT_FROM_U_GET_DATA(value))-0xa1a1)<=(0xfdfe - 0xa1a1) &&
1119                                      (uint8_t)(value-0xa1)<=(0xfe - 0xa1))) {
1120                                     continue;
1121                                 }
1122                                 break;
1123                             default:
1124                                 /*
1125                                  * UCNV_SET_FILTER_NONE,
1126                                  * or UCNV_SET_FILTER_DBCS_ONLY which is handled via minLength
1127                                  */
1128                                 break;
1129                             }
1130                             sa->add(sa->set, c);
1131                         }
1132                     } while((++c&0xf)!=0);
1133                 } else {
1134                     c+=16; /* empty stage 3 block */
1135                 }
1136             }
1137         } else {
1138             c+=1024; /* empty stage 2 block */
1139         }
1140     }
1141 }
1142 
1143 #endif /* #if !UCONFIG_NO_LEGACY_CONVERSION */
1144