1/*
2******************************************************************************
3*
4*   Copyright (C) 2003-2013, International Business Machines
5*   Corporation and others.  All Rights Reserved.
6*
7******************************************************************************
8*   file name:  ucnv_ext.cpp
9*   encoding:   US-ASCII
10*   tab size:   8 (not used)
11*   indentation:4
12*
13*   created on: 2003jun13
14*   created by: Markus W. Scherer
15*
16*   Conversion extensions
17*/
18
19#include "unicode/utypes.h"
20
21#if !UCONFIG_NO_CONVERSION && !UCONFIG_NO_LEGACY_CONVERSION
22
23#include "unicode/uset.h"
24#include "ucnv_bld.h"
25#include "ucnv_cnv.h"
26#include "ucnv_ext.h"
27#include "cmemory.h"
28#include "uassert.h"
29
30/* to Unicode --------------------------------------------------------------- */
31
32/*
33 * @return lookup value for the byte, if found; else 0
34 */
35static inline uint32_t
36ucnv_extFindToU(const uint32_t *toUSection, int32_t length, uint8_t byte) {
37    uint32_t word0, word;
38    int32_t i, start, limit;
39
40    /* check the input byte against the lowest and highest section bytes */
41    start=(int32_t)UCNV_EXT_TO_U_GET_BYTE(toUSection[0]);
42    limit=(int32_t)UCNV_EXT_TO_U_GET_BYTE(toUSection[length-1]);
43    if(byte<start || limit<byte) {
44        return 0; /* the byte is out of range */
45    }
46
47    if(length==((limit-start)+1)) {
48        /* direct access on a linear array */
49        return UCNV_EXT_TO_U_GET_VALUE(toUSection[byte-start]); /* could be 0 */
50    }
51
52    /* word0 is suitable for <=toUSection[] comparison, word for <toUSection[] */
53    word0=UCNV_EXT_TO_U_MAKE_WORD(byte, 0);
54
55    /*
56     * Shift byte once instead of each section word and add 0xffffff.
57     * We will compare the shifted/added byte (bbffffff) against
58     * section words which have byte values in the same bit position.
59     * If and only if byte bb < section byte ss then bbffffff<ssvvvvvv
60     * for all v=0..f
61     * so we need not mask off the lower 24 bits of each section word.
62     */
63    word=word0|UCNV_EXT_TO_U_VALUE_MASK;
64
65    /* binary search */
66    start=0;
67    limit=length;
68    for(;;) {
69        i=limit-start;
70        if(i<=1) {
71            break; /* done */
72        }
73        /* start<limit-1 */
74
75        if(i<=4) {
76            /* linear search for the last part */
77            if(word0<=toUSection[start]) {
78                break;
79            }
80            if(++start<limit && word0<=toUSection[start]) {
81                break;
82            }
83            if(++start<limit && word0<=toUSection[start]) {
84                break;
85            }
86            /* always break at start==limit-1 */
87            ++start;
88            break;
89        }
90
91        i=(start+limit)/2;
92        if(word<toUSection[i]) {
93            limit=i;
94        } else {
95            start=i;
96        }
97    }
98
99    /* did we really find it? */
100    if(start<limit && byte==UCNV_EXT_TO_U_GET_BYTE(word=toUSection[start])) {
101        return UCNV_EXT_TO_U_GET_VALUE(word); /* never 0 */
102    } else {
103        return 0; /* not found */
104    }
105}
106
107/*
108 * TRUE if not an SI/SO stateful converter,
109 * or if the match length fits with the current converter state
110 */
111#define UCNV_EXT_TO_U_VERIFY_SISO_MATCH(sisoState, match) \
112    ((sisoState)<0 || ((sisoState)==0) == (match==1))
113
114/*
115 * this works like ucnv_extMatchFromU() except
116 * - the first character is in pre
117 * - no trie is used
118 * - the returned matchLength is not offset by 2
119 */
120static int32_t
121ucnv_extMatchToU(const int32_t *cx, int8_t sisoState,
122                 const char *pre, int32_t preLength,
123                 const char *src, int32_t srcLength,
124                 uint32_t *pMatchValue,
125                 UBool /*useFallback*/, UBool flush) {
126    const uint32_t *toUTable, *toUSection;
127
128    uint32_t value, matchValue;
129    int32_t i, j, idx, length, matchLength;
130    uint8_t b;
131
132    if(cx==NULL || cx[UCNV_EXT_TO_U_LENGTH]<=0) {
133        return 0; /* no extension data, no match */
134    }
135
136    /* initialize */
137    toUTable=UCNV_EXT_ARRAY(cx, UCNV_EXT_TO_U_INDEX, uint32_t);
138    idx=0;
139
140    matchValue=0;
141    i=j=matchLength=0;
142
143    if(sisoState==0) {
144        /* SBCS state of an SI/SO stateful converter, look at only exactly 1 byte */
145        if(preLength>1) {
146            return 0; /* no match of a DBCS sequence in SBCS mode */
147        } else if(preLength==1) {
148            srcLength=0;
149        } else /* preLength==0 */ {
150            if(srcLength>1) {
151                srcLength=1;
152            }
153        }
154        flush=TRUE;
155    }
156
157    /* we must not remember fallback matches when not using fallbacks */
158
159    /* match input units until there is a full match or the input is consumed */
160    for(;;) {
161        /* go to the next section */
162        toUSection=toUTable+idx;
163
164        /* read first pair of the section */
165        value=*toUSection++;
166        length=UCNV_EXT_TO_U_GET_BYTE(value);
167        value=UCNV_EXT_TO_U_GET_VALUE(value);
168        if( value!=0 &&
169            (UCNV_EXT_TO_U_IS_ROUNDTRIP(value) ||
170             TO_U_USE_FALLBACK(useFallback)) &&
171            UCNV_EXT_TO_U_VERIFY_SISO_MATCH(sisoState, i+j)
172        ) {
173            /* remember longest match so far */
174            matchValue=value;
175            matchLength=i+j;
176        }
177
178        /* match pre[] then src[] */
179        if(i<preLength) {
180            b=(uint8_t)pre[i++];
181        } else if(j<srcLength) {
182            b=(uint8_t)src[j++];
183        } else {
184            /* all input consumed, partial match */
185            if(flush || (length=(i+j))>UCNV_EXT_MAX_BYTES) {
186                /*
187                 * end of the entire input stream, stop with the longest match so far
188                 * or: partial match must not be longer than UCNV_EXT_MAX_BYTES
189                 * because it must fit into state buffers
190                 */
191                break;
192            } else {
193                /* continue with more input next time */
194                return -length;
195            }
196        }
197
198        /* search for the current UChar */
199        value=ucnv_extFindToU(toUSection, length, b);
200        if(value==0) {
201            /* no match here, stop with the longest match so far */
202            break;
203        } else {
204            if(UCNV_EXT_TO_U_IS_PARTIAL(value)) {
205                /* partial match, continue */
206                idx=(int32_t)UCNV_EXT_TO_U_GET_PARTIAL_INDEX(value);
207            } else {
208                if( (UCNV_EXT_TO_U_IS_ROUNDTRIP(value) ||
209                     TO_U_USE_FALLBACK(useFallback)) &&
210                    UCNV_EXT_TO_U_VERIFY_SISO_MATCH(sisoState, i+j)
211                ) {
212                    /* full match, stop with result */
213                    matchValue=value;
214                    matchLength=i+j;
215                } else {
216                    /* full match on fallback not taken, stop with the longest match so far */
217                }
218                break;
219            }
220        }
221    }
222
223    if(matchLength==0) {
224        /* no match at all */
225        return 0;
226    }
227
228    /* return result */
229    *pMatchValue=UCNV_EXT_TO_U_MASK_ROUNDTRIP(matchValue);
230    return matchLength;
231}
232
233static inline void
234ucnv_extWriteToU(UConverter *cnv, const int32_t *cx,
235                 uint32_t value,
236                 UChar **target, const UChar *targetLimit,
237                 int32_t **offsets, int32_t srcIndex,
238                 UErrorCode *pErrorCode) {
239    /* output the result */
240    if(UCNV_EXT_TO_U_IS_CODE_POINT(value)) {
241        /* output a single code point */
242        ucnv_toUWriteCodePoint(
243            cnv, UCNV_EXT_TO_U_GET_CODE_POINT(value),
244            target, targetLimit,
245            offsets, srcIndex,
246            pErrorCode);
247    } else {
248        /* output a string - with correct data we have resultLength>0 */
249        ucnv_toUWriteUChars(
250            cnv,
251            UCNV_EXT_ARRAY(cx, UCNV_EXT_TO_U_UCHARS_INDEX, UChar)+
252                UCNV_EXT_TO_U_GET_INDEX(value),
253            UCNV_EXT_TO_U_GET_LENGTH(value),
254            target, targetLimit,
255            offsets, srcIndex,
256            pErrorCode);
257    }
258}
259
260/*
261 * get the SI/SO toU state (state 0 is for SBCS, 1 for DBCS),
262 * or 1 for DBCS-only,
263 * or -1 if the converter is not SI/SO stateful
264 *
265 * Note: For SI/SO stateful converters getting here,
266 * cnv->mode==0 is equivalent to firstLength==1.
267 */
268#define UCNV_SISO_STATE(cnv) \
269    ((cnv)->sharedData->mbcs.outputType==MBCS_OUTPUT_2_SISO ? (int8_t)(cnv)->mode : \
270     (cnv)->sharedData->mbcs.outputType==MBCS_OUTPUT_DBCS_ONLY ? 1 : -1)
271
272/*
273 * target<targetLimit; set error code for overflow
274 */
275U_CFUNC UBool
276ucnv_extInitialMatchToU(UConverter *cnv, const int32_t *cx,
277                        int32_t firstLength,
278                        const char **src, const char *srcLimit,
279                        UChar **target, const UChar *targetLimit,
280                        int32_t **offsets, int32_t srcIndex,
281                        UBool flush,
282                        UErrorCode *pErrorCode) {
283    uint32_t value = 0;  /* initialize output-only param to 0 to silence gcc */
284    int32_t match;
285
286    /* try to match */
287    match=ucnv_extMatchToU(cx, (int8_t)UCNV_SISO_STATE(cnv),
288                           (const char *)cnv->toUBytes, firstLength,
289                           *src, (int32_t)(srcLimit-*src),
290                           &value,
291                           cnv->useFallback, flush);
292    if(match>0) {
293        /* advance src pointer for the consumed input */
294        *src+=match-firstLength;
295
296        /* write result to target */
297        ucnv_extWriteToU(cnv, cx,
298                         value,
299                         target, targetLimit,
300                         offsets, srcIndex,
301                         pErrorCode);
302        return TRUE;
303    } else if(match<0) {
304        /* save state for partial match */
305        const char *s;
306        int32_t j;
307
308        /* copy the first code point */
309        s=(const char *)cnv->toUBytes;
310        cnv->preToUFirstLength=(int8_t)firstLength;
311        for(j=0; j<firstLength; ++j) {
312            cnv->preToU[j]=*s++;
313        }
314
315        /* now copy the newly consumed input */
316        s=*src;
317        match=-match;
318        for(; j<match; ++j) {
319            cnv->preToU[j]=*s++;
320        }
321        *src=s; /* same as *src=srcLimit; because we reached the end of input */
322        cnv->preToULength=(int8_t)match;
323        return TRUE;
324    } else /* match==0 no match */ {
325        return FALSE;
326    }
327}
328
329U_CFUNC UChar32
330ucnv_extSimpleMatchToU(const int32_t *cx,
331                       const char *source, int32_t length,
332                       UBool useFallback) {
333    uint32_t value = 0;  /* initialize output-only param to 0 to silence gcc */
334    int32_t match;
335
336    if(length<=0) {
337        return 0xffff;
338    }
339
340    /* try to match */
341    match=ucnv_extMatchToU(cx, -1,
342                           source, length,
343                           NULL, 0,
344                           &value,
345                           useFallback, TRUE);
346    if(match==length) {
347        /* write result for simple, single-character conversion */
348        if(UCNV_EXT_TO_U_IS_CODE_POINT(value)) {
349            return UCNV_EXT_TO_U_GET_CODE_POINT(value);
350        }
351    }
352
353    /*
354     * return no match because
355     * - match>0 && value points to string: simple conversion cannot handle multiple code points
356     * - match>0 && match!=length: not all input consumed, forbidden for this function
357     * - match==0: no match found in the first place
358     * - match<0: partial match, not supported for simple conversion (and flush==TRUE)
359     */
360    return 0xfffe;
361}
362
363/*
364 * continue partial match with new input
365 * never called for simple, single-character conversion
366 */
367U_CFUNC void
368ucnv_extContinueMatchToU(UConverter *cnv,
369                         UConverterToUnicodeArgs *pArgs, int32_t srcIndex,
370                         UErrorCode *pErrorCode) {
371    uint32_t value = 0;  /* initialize output-only param to 0 to silence gcc */
372    int32_t match, length;
373
374    match=ucnv_extMatchToU(cnv->sharedData->mbcs.extIndexes, (int8_t)UCNV_SISO_STATE(cnv),
375                           cnv->preToU, cnv->preToULength,
376                           pArgs->source, (int32_t)(pArgs->sourceLimit-pArgs->source),
377                           &value,
378                           cnv->useFallback, pArgs->flush);
379    if(match>0) {
380        if(match>=cnv->preToULength) {
381            /* advance src pointer for the consumed input */
382            pArgs->source+=match-cnv->preToULength;
383            cnv->preToULength=0;
384        } else {
385            /* the match did not use all of preToU[] - keep the rest for replay */
386            length=cnv->preToULength-match;
387            uprv_memmove(cnv->preToU, cnv->preToU+match, length);
388            cnv->preToULength=(int8_t)-length;
389        }
390
391        /* write result */
392        ucnv_extWriteToU(cnv, cnv->sharedData->mbcs.extIndexes,
393                         value,
394                         &pArgs->target, pArgs->targetLimit,
395                         &pArgs->offsets, srcIndex,
396                         pErrorCode);
397    } else if(match<0) {
398        /* save state for partial match */
399        const char *s;
400        int32_t j;
401
402        /* just _append_ the newly consumed input to preToU[] */
403        s=pArgs->source;
404        match=-match;
405        for(j=cnv->preToULength; j<match; ++j) {
406            cnv->preToU[j]=*s++;
407        }
408        pArgs->source=s; /* same as *src=srcLimit; because we reached the end of input */
409        cnv->preToULength=(int8_t)match;
410    } else /* match==0 */ {
411        /*
412         * no match
413         *
414         * We need to split the previous input into two parts:
415         *
416         * 1. The first codepage character is unmappable - that's how we got into
417         *    trying the extension data in the first place.
418         *    We need to move it from the preToU buffer
419         *    to the error buffer, set an error code,
420         *    and prepare the rest of the previous input for 2.
421         *
422         * 2. The rest of the previous input must be converted once we
423         *    come back from the callback for the first character.
424         *    At that time, we have to try again from scratch to convert
425         *    these input characters.
426         *    The replay will be handled by the ucnv.c conversion code.
427         */
428
429        /* move the first codepage character to the error field */
430        uprv_memcpy(cnv->toUBytes, cnv->preToU, cnv->preToUFirstLength);
431        cnv->toULength=cnv->preToUFirstLength;
432
433        /* move the rest up inside the buffer */
434        length=cnv->preToULength-cnv->preToUFirstLength;
435        if(length>0) {
436            uprv_memmove(cnv->preToU, cnv->preToU+cnv->preToUFirstLength, length);
437        }
438
439        /* mark preToU for replay */
440        cnv->preToULength=(int8_t)-length;
441
442        /* set the error code for unassigned */
443        *pErrorCode=U_INVALID_CHAR_FOUND;
444    }
445}
446
447/* from Unicode ------------------------------------------------------------- */
448
449// Use roundtrips, "good one-way" mappings, and some normal fallbacks.
450static inline UBool
451extFromUUseMapping(UBool useFallback, uint32_t value, UChar32 firstCP) {
452    return
453        ((value&UCNV_EXT_FROM_U_STATUS_MASK)!=0 ||
454            FROM_U_USE_FALLBACK(useFallback, firstCP)) &&
455        (value&UCNV_EXT_FROM_U_RESERVED_MASK)==0;
456}
457
458/*
459 * @return index of the UChar, if found; else <0
460 */
461static inline int32_t
462ucnv_extFindFromU(const UChar *fromUSection, int32_t length, UChar u) {
463    int32_t i, start, limit;
464
465    /* binary search */
466    start=0;
467    limit=length;
468    for(;;) {
469        i=limit-start;
470        if(i<=1) {
471            break; /* done */
472        }
473        /* start<limit-1 */
474
475        if(i<=4) {
476            /* linear search for the last part */
477            if(u<=fromUSection[start]) {
478                break;
479            }
480            if(++start<limit && u<=fromUSection[start]) {
481                break;
482            }
483            if(++start<limit && u<=fromUSection[start]) {
484                break;
485            }
486            /* always break at start==limit-1 */
487            ++start;
488            break;
489        }
490
491        i=(start+limit)/2;
492        if(u<fromUSection[i]) {
493            limit=i;
494        } else {
495            start=i;
496        }
497    }
498
499    /* did we really find it? */
500    if(start<limit && u==fromUSection[start]) {
501        return start;
502    } else {
503        return -1; /* not found */
504    }
505}
506
507/*
508 * @param cx pointer to extension data; if NULL, returns 0
509 * @param firstCP the first code point before all the other UChars
510 * @param pre UChars that must match; !initialMatch: partial match with them
511 * @param preLength length of pre, >=0
512 * @param src UChars that can be used to complete a match
513 * @param srcLength length of src, >=0
514 * @param pMatchValue [out] output result value for the match from the data structure
515 * @param useFallback "use fallback" flag, usually from cnv->useFallback
516 * @param flush TRUE if the end of the input stream is reached
517 * @return >1: matched, return value=total match length (number of input units matched)
518 *          1: matched, no mapping but request for <subchar1>
519 *             (only for the first code point)
520 *          0: no match
521 *         <0: partial match, return value=negative total match length
522 *             (partial matches are never returned for flush==TRUE)
523 *             (partial matches are never returned as being longer than UCNV_EXT_MAX_UCHARS)
524 *         the matchLength is 2 if only firstCP matched, and >2 if firstCP and
525 *         further code units matched
526 */
527static int32_t
528ucnv_extMatchFromU(const int32_t *cx,
529                   UChar32 firstCP,
530                   const UChar *pre, int32_t preLength,
531                   const UChar *src, int32_t srcLength,
532                   uint32_t *pMatchValue,
533                   UBool useFallback, UBool flush) {
534    const uint16_t *stage12, *stage3;
535    const uint32_t *stage3b;
536
537    const UChar *fromUTableUChars, *fromUSectionUChars;
538    const uint32_t *fromUTableValues, *fromUSectionValues;
539
540    uint32_t value, matchValue;
541    int32_t i, j, idx, length, matchLength;
542    UChar c;
543
544    if(cx==NULL) {
545        return 0; /* no extension data, no match */
546    }
547
548    /* trie lookup of firstCP */
549    idx=firstCP>>10; /* stage 1 index */
550    if(idx>=cx[UCNV_EXT_FROM_U_STAGE_1_LENGTH]) {
551        return 0; /* the first code point is outside the trie */
552    }
553
554    stage12=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_12_INDEX, uint16_t);
555    stage3=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_3_INDEX, uint16_t);
556    idx=UCNV_EXT_FROM_U(stage12, stage3, idx, firstCP);
557
558    stage3b=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_3B_INDEX, uint32_t);
559    value=stage3b[idx];
560    if(value==0) {
561        return 0;
562    }
563
564    /*
565     * Tests for (value&UCNV_EXT_FROM_U_RESERVED_MASK)==0:
566     * Do not interpret values with reserved bits used, for forward compatibility,
567     * and do not even remember intermediate results with reserved bits used.
568     */
569
570    if(UCNV_EXT_TO_U_IS_PARTIAL(value)) {
571        /* partial match, enter the loop below */
572        idx=(int32_t)UCNV_EXT_FROM_U_GET_PARTIAL_INDEX(value);
573
574        /* initialize */
575        fromUTableUChars=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_UCHARS_INDEX, UChar);
576        fromUTableValues=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_VALUES_INDEX, uint32_t);
577
578        matchValue=0;
579        i=j=matchLength=0;
580
581        /* we must not remember fallback matches when not using fallbacks */
582
583        /* match input units until there is a full match or the input is consumed */
584        for(;;) {
585            /* go to the next section */
586            fromUSectionUChars=fromUTableUChars+idx;
587            fromUSectionValues=fromUTableValues+idx;
588
589            /* read first pair of the section */
590            length=*fromUSectionUChars++;
591            value=*fromUSectionValues++;
592            if(value!=0 && extFromUUseMapping(useFallback, value, firstCP)) {
593                /* remember longest match so far */
594                matchValue=value;
595                matchLength=2+i+j;
596            }
597
598            /* match pre[] then src[] */
599            if(i<preLength) {
600                c=pre[i++];
601            } else if(j<srcLength) {
602                c=src[j++];
603            } else {
604                /* all input consumed, partial match */
605                if(flush || (length=(i+j))>UCNV_EXT_MAX_UCHARS) {
606                    /*
607                     * end of the entire input stream, stop with the longest match so far
608                     * or: partial match must not be longer than UCNV_EXT_MAX_UCHARS
609                     * because it must fit into state buffers
610                     */
611                    break;
612                } else {
613                    /* continue with more input next time */
614                    return -(2+length);
615                }
616            }
617
618            /* search for the current UChar */
619            idx=ucnv_extFindFromU(fromUSectionUChars, length, c);
620            if(idx<0) {
621                /* no match here, stop with the longest match so far */
622                break;
623            } else {
624                value=fromUSectionValues[idx];
625                if(UCNV_EXT_FROM_U_IS_PARTIAL(value)) {
626                    /* partial match, continue */
627                    idx=(int32_t)UCNV_EXT_FROM_U_GET_PARTIAL_INDEX(value);
628                } else {
629                    if(extFromUUseMapping(useFallback, value, firstCP)) {
630                        /* full match, stop with result */
631                        matchValue=value;
632                        matchLength=2+i+j;
633                    } else {
634                        /* full match on fallback not taken, stop with the longest match so far */
635                    }
636                    break;
637                }
638            }
639        }
640
641        if(matchLength==0) {
642            /* no match at all */
643            return 0;
644        }
645    } else /* result from firstCP trie lookup */ {
646        if(extFromUUseMapping(useFallback, value, firstCP)) {
647            /* full match, stop with result */
648            matchValue=value;
649            matchLength=2;
650        } else {
651            /* fallback not taken */
652            return 0;
653        }
654    }
655
656    /* return result */
657    if(matchValue==UCNV_EXT_FROM_U_SUBCHAR1) {
658        return 1; /* assert matchLength==2 */
659    }
660
661    *pMatchValue=matchValue;
662    return matchLength;
663}
664
665/*
666 * @param value fromUnicode mapping table value; ignores roundtrip and reserved bits
667 */
668static inline void
669ucnv_extWriteFromU(UConverter *cnv, const int32_t *cx,
670                   uint32_t value,
671                   char **target, const char *targetLimit,
672                   int32_t **offsets, int32_t srcIndex,
673                   UErrorCode *pErrorCode) {
674    uint8_t buffer[1+UCNV_EXT_MAX_BYTES];
675    const uint8_t *result;
676    int32_t length, prevLength;
677
678    length=UCNV_EXT_FROM_U_GET_LENGTH(value);
679    value=(uint32_t)UCNV_EXT_FROM_U_GET_DATA(value);
680
681    /* output the result */
682    if(length<=UCNV_EXT_FROM_U_MAX_DIRECT_LENGTH) {
683        /*
684         * Generate a byte array and then write it below.
685         * This is not the fastest possible way, but it should be ok for
686         * extension mappings, and it is much simpler.
687         * Offset and overflow handling are only done once this way.
688         */
689        uint8_t *p=buffer+1; /* reserve buffer[0] for shiftByte below */
690        switch(length) {
691        case 3:
692            *p++=(uint8_t)(value>>16);
693        case 2: /*fall through*/
694            *p++=(uint8_t)(value>>8);
695        case 1: /*fall through*/
696            *p++=(uint8_t)value;
697        default:
698            break; /* will never occur */
699        }
700        result=buffer+1;
701    } else {
702        result=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_BYTES_INDEX, uint8_t)+value;
703    }
704
705    /* with correct data we have length>0 */
706
707    if((prevLength=cnv->fromUnicodeStatus)!=0) {
708        /* handle SI/SO stateful output */
709        uint8_t shiftByte;
710
711        if(prevLength>1 && length==1) {
712            /* change from double-byte mode to single-byte */
713            shiftByte=(uint8_t)UCNV_SI;
714            cnv->fromUnicodeStatus=1;
715        } else if(prevLength==1 && length>1) {
716            /* change from single-byte mode to double-byte */
717            shiftByte=(uint8_t)UCNV_SO;
718            cnv->fromUnicodeStatus=2;
719        } else {
720            shiftByte=0;
721        }
722
723        if(shiftByte!=0) {
724            /* prepend the shift byte to the result bytes */
725            buffer[0]=shiftByte;
726            if(result!=buffer+1) {
727                uprv_memcpy(buffer+1, result, length);
728            }
729            result=buffer;
730            ++length;
731        }
732    }
733
734    ucnv_fromUWriteBytes(cnv, (const char *)result, length,
735                         target, targetLimit,
736                         offsets, srcIndex,
737                         pErrorCode);
738}
739
740/*
741 * target<targetLimit; set error code for overflow
742 */
743U_CFUNC UBool
744ucnv_extInitialMatchFromU(UConverter *cnv, const int32_t *cx,
745                          UChar32 cp,
746                          const UChar **src, const UChar *srcLimit,
747                          char **target, const char *targetLimit,
748                          int32_t **offsets, int32_t srcIndex,
749                          UBool flush,
750                          UErrorCode *pErrorCode) {
751    uint32_t value = 0;  /* initialize output-only param to 0 to silence gcc */
752    int32_t match;
753
754    /* try to match */
755    match=ucnv_extMatchFromU(cx, cp,
756                             NULL, 0,
757                             *src, (int32_t)(srcLimit-*src),
758                             &value,
759                             cnv->useFallback, flush);
760
761    /* reject a match if the result is a single byte for DBCS-only */
762    if( match>=2 &&
763        !(UCNV_EXT_FROM_U_GET_LENGTH(value)==1 &&
764          cnv->sharedData->mbcs.outputType==MBCS_OUTPUT_DBCS_ONLY)
765    ) {
766        /* advance src pointer for the consumed input */
767        *src+=match-2; /* remove 2 for the initial code point */
768
769        /* write result to target */
770        ucnv_extWriteFromU(cnv, cx,
771                           value,
772                           target, targetLimit,
773                           offsets, srcIndex,
774                           pErrorCode);
775        return TRUE;
776    } else if(match<0) {
777        /* save state for partial match */
778        const UChar *s;
779        int32_t j;
780
781        /* copy the first code point */
782        cnv->preFromUFirstCP=cp;
783
784        /* now copy the newly consumed input */
785        s=*src;
786        match=-match-2; /* remove 2 for the initial code point */
787        for(j=0; j<match; ++j) {
788            cnv->preFromU[j]=*s++;
789        }
790        *src=s; /* same as *src=srcLimit; because we reached the end of input */
791        cnv->preFromULength=(int8_t)match;
792        return TRUE;
793    } else if(match==1) {
794        /* matched, no mapping but request for <subchar1> */
795        cnv->useSubChar1=TRUE;
796        return FALSE;
797    } else /* match==0 no match */ {
798        return FALSE;
799    }
800}
801
802/*
803 * Used by ISO 2022 implementation.
804 * @return number of bytes in *pValue; negative number if fallback; 0 for no mapping
805 */
806U_CFUNC int32_t
807ucnv_extSimpleMatchFromU(const int32_t *cx,
808                         UChar32 cp, uint32_t *pValue,
809                         UBool useFallback) {
810    uint32_t value;
811    int32_t match;
812
813    /* try to match */
814    match=ucnv_extMatchFromU(cx,
815                             cp,
816                             NULL, 0,
817                             NULL, 0,
818                             &value,
819                             useFallback, TRUE);
820    if(match>=2) {
821        /* write result for simple, single-character conversion */
822        int32_t length;
823        int isRoundtrip;
824
825        isRoundtrip=UCNV_EXT_FROM_U_IS_ROUNDTRIP(value);
826        length=UCNV_EXT_FROM_U_GET_LENGTH(value);
827        value=(uint32_t)UCNV_EXT_FROM_U_GET_DATA(value);
828
829        if(length<=UCNV_EXT_FROM_U_MAX_DIRECT_LENGTH) {
830            *pValue=value;
831            return isRoundtrip ? length : -length;
832#if 0 /* not currently used */
833        } else if(length==4) {
834            /* de-serialize a 4-byte result */
835            const uint8_t *result=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_BYTES_INDEX, uint8_t)+value;
836            *pValue=
837                ((uint32_t)result[0]<<24)|
838                ((uint32_t)result[1]<<16)|
839                ((uint32_t)result[2]<<8)|
840                result[3];
841            return isRoundtrip ? 4 : -4;
842#endif
843        }
844    }
845
846    /*
847     * return no match because
848     * - match>1 && resultLength>4: result too long for simple conversion
849     * - match==1: no match found, <subchar1> preferred
850     * - match==0: no match found in the first place
851     * - match<0: partial match, not supported for simple conversion (and flush==TRUE)
852     */
853    return 0;
854}
855
856/*
857 * continue partial match with new input, requires cnv->preFromUFirstCP>=0
858 * never called for simple, single-character conversion
859 */
860U_CFUNC void
861ucnv_extContinueMatchFromU(UConverter *cnv,
862                           UConverterFromUnicodeArgs *pArgs, int32_t srcIndex,
863                           UErrorCode *pErrorCode) {
864    uint32_t value = 0;  /* initialize output-only param to 0 to silence gcc */
865    int32_t match;
866
867    match=ucnv_extMatchFromU(cnv->sharedData->mbcs.extIndexes,
868                             cnv->preFromUFirstCP,
869                             cnv->preFromU, cnv->preFromULength,
870                             pArgs->source, (int32_t)(pArgs->sourceLimit-pArgs->source),
871                             &value,
872                             cnv->useFallback, pArgs->flush);
873    if(match>=2) {
874        match-=2; /* remove 2 for the initial code point */
875
876        if(match>=cnv->preFromULength) {
877            /* advance src pointer for the consumed input */
878            pArgs->source+=match-cnv->preFromULength;
879            cnv->preFromULength=0;
880        } else {
881            /* the match did not use all of preFromU[] - keep the rest for replay */
882            int32_t length=cnv->preFromULength-match;
883            uprv_memmove(cnv->preFromU, cnv->preFromU+match, length*U_SIZEOF_UCHAR);
884            cnv->preFromULength=(int8_t)-length;
885        }
886
887        /* finish the partial match */
888        cnv->preFromUFirstCP=U_SENTINEL;
889
890        /* write result */
891        ucnv_extWriteFromU(cnv, cnv->sharedData->mbcs.extIndexes,
892                           value,
893                           &pArgs->target, pArgs->targetLimit,
894                           &pArgs->offsets, srcIndex,
895                           pErrorCode);
896    } else if(match<0) {
897        /* save state for partial match */
898        const UChar *s;
899        int32_t j;
900
901        /* just _append_ the newly consumed input to preFromU[] */
902        s=pArgs->source;
903        match=-match-2; /* remove 2 for the initial code point */
904        for(j=cnv->preFromULength; j<match; ++j) {
905            U_ASSERT(j>=0);
906            cnv->preFromU[j]=*s++;
907        }
908        pArgs->source=s; /* same as *src=srcLimit; because we reached the end of input */
909        cnv->preFromULength=(int8_t)match;
910    } else /* match==0 or 1 */ {
911        /*
912         * no match
913         *
914         * We need to split the previous input into two parts:
915         *
916         * 1. The first code point is unmappable - that's how we got into
917         *    trying the extension data in the first place.
918         *    We need to move it from the preFromU buffer
919         *    to the error buffer, set an error code,
920         *    and prepare the rest of the previous input for 2.
921         *
922         * 2. The rest of the previous input must be converted once we
923         *    come back from the callback for the first code point.
924         *    At that time, we have to try again from scratch to convert
925         *    these input characters.
926         *    The replay will be handled by the ucnv.c conversion code.
927         */
928
929        if(match==1) {
930            /* matched, no mapping but request for <subchar1> */
931            cnv->useSubChar1=TRUE;
932        }
933
934        /* move the first code point to the error field */
935        cnv->fromUChar32=cnv->preFromUFirstCP;
936        cnv->preFromUFirstCP=U_SENTINEL;
937
938        /* mark preFromU for replay */
939        cnv->preFromULength=-cnv->preFromULength;
940
941        /* set the error code for unassigned */
942        *pErrorCode=U_INVALID_CHAR_FOUND;
943    }
944}
945
946static UBool
947extSetUseMapping(UConverterUnicodeSet which, int32_t minLength, uint32_t value) {
948    if(which==UCNV_ROUNDTRIP_SET) {
949        // Add only code points for which the roundtrip flag is set.
950        // Do not add any fallbacks, even if ucnv_fromUnicode() would use them
951        // (fallbacks from PUA). See the API docs for ucnv_getUnicodeSet().
952        //
953        // By analogy, also do not add "good one-way" mappings.
954        //
955        // Do not add entries with reserved bits set.
956        if(((value&(UCNV_EXT_FROM_U_ROUNDTRIP_FLAG|UCNV_EXT_FROM_U_RESERVED_MASK))!=
957                UCNV_EXT_FROM_U_ROUNDTRIP_FLAG)) {
958            return FALSE;
959        }
960    } else /* UCNV_ROUNDTRIP_AND_FALLBACK_SET */ {
961        // Do not add entries with reserved bits set.
962        if((value&UCNV_EXT_FROM_U_RESERVED_MASK)!=0) {
963            return FALSE;
964        }
965    }
966    // Do not add <subchar1> entries or other (future?) pseudo-entries
967    // with an output length of 0.
968    return UCNV_EXT_FROM_U_GET_LENGTH(value)>=minLength;
969}
970
971static void
972ucnv_extGetUnicodeSetString(const UConverterSharedData *sharedData,
973                            const int32_t *cx,
974                            const USetAdder *sa,
975                            UConverterUnicodeSet which,
976                            int32_t minLength,
977                            UChar32 firstCP,
978                            UChar s[UCNV_EXT_MAX_UCHARS], int32_t length,
979                            int32_t sectionIndex,
980                            UErrorCode *pErrorCode) {
981    const UChar *fromUSectionUChars;
982    const uint32_t *fromUSectionValues;
983
984    uint32_t value;
985    int32_t i, count;
986
987    fromUSectionUChars=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_UCHARS_INDEX, UChar)+sectionIndex;
988    fromUSectionValues=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_VALUES_INDEX, uint32_t)+sectionIndex;
989
990    /* read first pair of the section */
991    count=*fromUSectionUChars++;
992    value=*fromUSectionValues++;
993
994    if(extSetUseMapping(which, minLength, value)) {
995        if(length==U16_LENGTH(firstCP)) {
996            /* add the initial code point */
997            sa->add(sa->set, firstCP);
998        } else {
999            /* add the string so far */
1000            sa->addString(sa->set, s, length);
1001        }
1002    }
1003
1004    for(i=0; i<count; ++i) {
1005        /* append this code unit and recurse or add the string */
1006        s[length]=fromUSectionUChars[i];
1007        value=fromUSectionValues[i];
1008
1009        if(value==0) {
1010            /* no mapping, do nothing */
1011        } else if(UCNV_EXT_FROM_U_IS_PARTIAL(value)) {
1012            ucnv_extGetUnicodeSetString(
1013                sharedData, cx, sa, which, minLength,
1014                firstCP, s, length+1,
1015                (int32_t)UCNV_EXT_FROM_U_GET_PARTIAL_INDEX(value),
1016                pErrorCode);
1017        } else if(extSetUseMapping(which, minLength, value)) {
1018            sa->addString(sa->set, s, length+1);
1019        }
1020    }
1021}
1022
1023U_CFUNC void
1024ucnv_extGetUnicodeSet(const UConverterSharedData *sharedData,
1025                      const USetAdder *sa,
1026                      UConverterUnicodeSet which,
1027                      UConverterSetFilter filter,
1028                      UErrorCode *pErrorCode) {
1029    const int32_t *cx;
1030    const uint16_t *stage12, *stage3, *ps2, *ps3;
1031    const uint32_t *stage3b;
1032
1033    uint32_t value;
1034    int32_t st1, stage1Length, st2, st3, minLength;
1035
1036    UChar s[UCNV_EXT_MAX_UCHARS];
1037    UChar32 c;
1038    int32_t length;
1039
1040    cx=sharedData->mbcs.extIndexes;
1041    if(cx==NULL) {
1042        return;
1043    }
1044
1045    stage12=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_12_INDEX, uint16_t);
1046    stage3=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_3_INDEX, uint16_t);
1047    stage3b=UCNV_EXT_ARRAY(cx, UCNV_EXT_FROM_U_STAGE_3B_INDEX, uint32_t);
1048
1049    stage1Length=cx[UCNV_EXT_FROM_U_STAGE_1_LENGTH];
1050
1051    /* enumerate the from-Unicode trie table */
1052    c=0; /* keep track of the current code point while enumerating */
1053
1054    if(filter==UCNV_SET_FILTER_2022_CN) {
1055        minLength=3;
1056    } else if( sharedData->mbcs.outputType==MBCS_OUTPUT_DBCS_ONLY ||
1057               filter!=UCNV_SET_FILTER_NONE
1058    ) {
1059        /* DBCS-only, ignore single-byte results */
1060        minLength=2;
1061    } else {
1062        minLength=1;
1063    }
1064
1065    /*
1066     * the trie enumeration is almost the same as
1067     * in MBCSGetUnicodeSet() for MBCS_OUTPUT_1
1068     */
1069    for(st1=0; st1<stage1Length; ++st1) {
1070        st2=stage12[st1];
1071        if(st2>stage1Length) {
1072            ps2=stage12+st2;
1073            for(st2=0; st2<64; ++st2) {
1074                if((st3=(int32_t)ps2[st2]<<UCNV_EXT_STAGE_2_LEFT_SHIFT)!=0) {
1075                    /* read the stage 3 block */
1076                    ps3=stage3+st3;
1077
1078                    do {
1079                        value=stage3b[*ps3++];
1080                        if(value==0) {
1081                            /* no mapping, do nothing */
1082                        } else if(UCNV_EXT_FROM_U_IS_PARTIAL(value)) {
1083                            // Recurse for partial results.
1084                            length=0;
1085                            U16_APPEND_UNSAFE(s, length, c);
1086                            ucnv_extGetUnicodeSetString(
1087                                sharedData, cx, sa, which, minLength,
1088                                c, s, length,
1089                                (int32_t)UCNV_EXT_FROM_U_GET_PARTIAL_INDEX(value),
1090                                pErrorCode);
1091                        } else if(extSetUseMapping(which, minLength, value)) {
1092                            switch(filter) {
1093                            case UCNV_SET_FILTER_2022_CN:
1094                                if(!(UCNV_EXT_FROM_U_GET_LENGTH(value)==3 && UCNV_EXT_FROM_U_GET_DATA(value)<=0x82ffff)) {
1095                                    continue;
1096                                }
1097                                break;
1098                            case UCNV_SET_FILTER_SJIS:
1099                                if(!(UCNV_EXT_FROM_U_GET_LENGTH(value)==2 && (value=UCNV_EXT_FROM_U_GET_DATA(value))>=0x8140 && value<=0xeffc)) {
1100                                    continue;
1101                                }
1102                                break;
1103                            case UCNV_SET_FILTER_GR94DBCS:
1104                                if(!(UCNV_EXT_FROM_U_GET_LENGTH(value)==2 &&
1105                                     (uint16_t)((value=UCNV_EXT_FROM_U_GET_DATA(value))-0xa1a1)<=(0xfefe - 0xa1a1) &&
1106                                     (uint8_t)(value-0xa1)<=(0xfe - 0xa1))) {
1107                                    continue;
1108                                }
1109                                break;
1110                            case UCNV_SET_FILTER_HZ:
1111                                if(!(UCNV_EXT_FROM_U_GET_LENGTH(value)==2 &&
1112                                     (uint16_t)((value=UCNV_EXT_FROM_U_GET_DATA(value))-0xa1a1)<=(0xfdfe - 0xa1a1) &&
1113                                     (uint8_t)(value-0xa1)<=(0xfe - 0xa1))) {
1114                                    continue;
1115                                }
1116                                break;
1117                            default:
1118                                /*
1119                                 * UCNV_SET_FILTER_NONE,
1120                                 * or UCNV_SET_FILTER_DBCS_ONLY which is handled via minLength
1121                                 */
1122                                break;
1123                            }
1124                            sa->add(sa->set, c);
1125                        }
1126                    } while((++c&0xf)!=0);
1127                } else {
1128                    c+=16; /* empty stage 3 block */
1129                }
1130            }
1131        } else {
1132            c+=1024; /* empty stage 2 block */
1133        }
1134    }
1135}
1136
1137#endif /* #if !UCONFIG_NO_LEGACY_CONVERSION */
1138