1/*
2*******************************************************************************
3*
4*   Copyright (C) 2001-2015, International Business Machines
5*   Corporation and others.  All Rights Reserved.
6*
7*******************************************************************************
8*   file name:  ustrcase.cpp
9*   encoding:   US-ASCII
10*   tab size:   8 (not used)
11*   indentation:4
12*
13*   created on: 2002feb20
14*   created by: Markus W. Scherer
15*
16*   Implementation file for string casing C API functions.
17*   Uses functions from uchar.c for basic functionality that requires access
18*   to the Unicode Character Database (uprops.dat).
19*/
20
21#include "unicode/utypes.h"
22#include "unicode/brkiter.h"
23#include "unicode/ustring.h"
24#include "unicode/ucasemap.h"
25#include "unicode/ubrk.h"
26#include "unicode/utf.h"
27#include "unicode/utf16.h"
28#include "cmemory.h"
29#include "ucase.h"
30#include "ustr_imp.h"
31#include "uassert.h"
32
33U_NAMESPACE_USE
34
35/* string casing ------------------------------------------------------------ */
36
37/* Appends a full case mapping result, see UCASE_MAX_STRING_LENGTH. */
38static inline int32_t
39appendResult(UChar *dest, int32_t destIndex, int32_t destCapacity,
40             int32_t result, const UChar *s) {
41    UChar32 c;
42    int32_t length;
43
44    /* decode the result */
45    if(result<0) {
46        /* (not) original code point */
47        c=~result;
48        length=-1;
49    } else if(result<=UCASE_MAX_STRING_LENGTH) {
50        c=U_SENTINEL;
51        length=result;
52    } else {
53        c=result;
54        length=-1;
55    }
56
57    if(destIndex<destCapacity) {
58        /* append the result */
59        if(length<0) {
60            /* code point */
61            UBool isError=FALSE;
62            U16_APPEND(dest, destIndex, destCapacity, c, isError);
63            if(isError) {
64                /* overflow, nothing written */
65                destIndex+=U16_LENGTH(c);
66            }
67        } else {
68            /* string */
69            if((destIndex+length)<=destCapacity) {
70                while(length>0) {
71                    dest[destIndex++]=*s++;
72                    --length;
73                }
74            } else {
75                /* overflow */
76                destIndex+=length;
77            }
78        }
79    } else {
80        /* preflight */
81        if(length<0) {
82            destIndex+=U16_LENGTH(c);
83        } else {
84            destIndex+=length;
85        }
86    }
87    return destIndex;
88}
89
90static UChar32 U_CALLCONV
91utf16_caseContextIterator(void *context, int8_t dir) {
92    UCaseContext *csc=(UCaseContext *)context;
93    UChar32 c;
94
95    if(dir<0) {
96        /* reset for backward iteration */
97        csc->index=csc->cpStart;
98        csc->dir=dir;
99    } else if(dir>0) {
100        /* reset for forward iteration */
101        csc->index=csc->cpLimit;
102        csc->dir=dir;
103    } else {
104        /* continue current iteration direction */
105        dir=csc->dir;
106    }
107
108    if(dir<0) {
109        if(csc->start<csc->index) {
110            U16_PREV((const UChar *)csc->p, csc->start, csc->index, c);
111            return c;
112        }
113    } else {
114        if(csc->index<csc->limit) {
115            U16_NEXT((const UChar *)csc->p, csc->index, csc->limit, c);
116            return c;
117        }
118    }
119    return U_SENTINEL;
120}
121
122/*
123 * Case-maps [srcStart..srcLimit[ but takes
124 * context [0..srcLength[ into account.
125 */
126static int32_t
127_caseMap(const UCaseMap *csm, UCaseMapFull *map,
128         UChar *dest, int32_t destCapacity,
129         const UChar *src, UCaseContext *csc,
130         int32_t srcStart, int32_t srcLimit,
131         UErrorCode *pErrorCode) {
132    const UChar *s;
133    UChar32 c, c2 = 0;
134    int32_t srcIndex, destIndex;
135    int32_t locCache;
136
137    locCache=csm->locCache;
138
139    /* case mapping loop */
140    srcIndex=srcStart;
141    destIndex=0;
142    while(srcIndex<srcLimit) {
143        csc->cpStart=srcIndex;
144        U16_NEXT(src, srcIndex, srcLimit, c);
145        csc->cpLimit=srcIndex;
146        c=map(csm->csp, c, utf16_caseContextIterator, csc, &s, csm->locale, &locCache);
147        if((destIndex<destCapacity) && (c<0 ? (c2=~c)<=0xffff : UCASE_MAX_STRING_LENGTH<c && (c2=c)<=0xffff)) {
148            /* fast path version of appendResult() for BMP results */
149            dest[destIndex++]=(UChar)c2;
150        } else {
151            destIndex=appendResult(dest, destIndex, destCapacity, c, s);
152        }
153    }
154
155    if(destIndex>destCapacity) {
156        *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
157    }
158    return destIndex;
159}
160
161#if !UCONFIG_NO_BREAK_ITERATION
162
163U_CFUNC int32_t U_CALLCONV
164ustrcase_internalToTitle(const UCaseMap *csm,
165                         UChar *dest, int32_t destCapacity,
166                         const UChar *src, int32_t srcLength,
167                         UErrorCode *pErrorCode) {
168    const UChar *s;
169    UChar32 c;
170    int32_t prev, titleStart, titleLimit, idx, destIndex, length;
171    UBool isFirstIndex;
172
173    if(U_FAILURE(*pErrorCode)) {
174        return 0;
175    }
176
177    // Use the C++ abstract base class to minimize dependencies.
178    // TODO: Change UCaseMap.iter to store a BreakIterator directly.
179    BreakIterator *bi=reinterpret_cast<BreakIterator *>(csm->iter);
180
181    /* set up local variables */
182    int32_t locCache=csm->locCache;
183    UCaseContext csc=UCASECONTEXT_INITIALIZER;
184    csc.p=(void *)src;
185    csc.limit=srcLength;
186    destIndex=0;
187    prev=0;
188    isFirstIndex=TRUE;
189
190    /* titlecasing loop */
191    while(prev<srcLength) {
192        /* find next index where to titlecase */
193        if(isFirstIndex) {
194            isFirstIndex=FALSE;
195            idx=bi->first();
196        } else {
197            idx=bi->next();
198        }
199        if(idx==UBRK_DONE || idx>srcLength) {
200            idx=srcLength;
201        }
202
203        /*
204         * Unicode 4 & 5 section 3.13 Default Case Operations:
205         *
206         * R3  toTitlecase(X): Find the word boundaries based on Unicode Standard Annex
207         * #29, "Text Boundaries." Between each pair of word boundaries, find the first
208         * cased character F. If F exists, map F to default_title(F); then map each
209         * subsequent character C to default_lower(C).
210         *
211         * In this implementation, segment [prev..index[ into 3 parts:
212         * a) uncased characters (copy as-is) [prev..titleStart[
213         * b) first case letter (titlecase)         [titleStart..titleLimit[
214         * c) subsequent characters (lowercase)                 [titleLimit..index[
215         */
216        if(prev<idx) {
217            /* find and copy uncased characters [prev..titleStart[ */
218            titleStart=titleLimit=prev;
219            U16_NEXT(src, titleLimit, idx, c);
220            if((csm->options&U_TITLECASE_NO_BREAK_ADJUSTMENT)==0 && UCASE_NONE==ucase_getType(csm->csp, c)) {
221                /* Adjust the titlecasing index (titleStart) to the next cased character. */
222                for(;;) {
223                    titleStart=titleLimit;
224                    if(titleLimit==idx) {
225                        /*
226                         * only uncased characters in [prev..index[
227                         * stop with titleStart==titleLimit==index
228                         */
229                        break;
230                    }
231                    U16_NEXT(src, titleLimit, idx, c);
232                    if(UCASE_NONE!=ucase_getType(csm->csp, c)) {
233                        break; /* cased letter at [titleStart..titleLimit[ */
234                    }
235                }
236                length=titleStart-prev;
237                if(length>0) {
238                    if((destIndex+length)<=destCapacity) {
239                        uprv_memcpy(dest+destIndex, src+prev, length*U_SIZEOF_UCHAR);
240                    }
241                    destIndex+=length;
242                }
243            }
244
245            if(titleStart<titleLimit) {
246                /* titlecase c which is from [titleStart..titleLimit[ */
247                csc.cpStart=titleStart;
248                csc.cpLimit=titleLimit;
249                c=ucase_toFullTitle(csm->csp, c, utf16_caseContextIterator, &csc, &s, csm->locale, &locCache);
250                destIndex=appendResult(dest, destIndex, destCapacity, c, s);
251
252                /* Special case Dutch IJ titlecasing */
253                if ( titleStart+1 < idx &&
254                     ucase_getCaseLocale(csm->locale,&locCache) == UCASE_LOC_DUTCH &&
255                     ( src[titleStart] == (UChar32) 0x0049 || src[titleStart] == (UChar32) 0x0069 ) &&
256                     ( src[titleStart+1] == (UChar32) 0x004A || src[titleStart+1] == (UChar32) 0x006A )) {
257                            c=(UChar32) 0x004A;
258                            destIndex=appendResult(dest, destIndex, destCapacity, c, s);
259                            titleLimit++;
260                }
261
262                /* lowercase [titleLimit..index[ */
263                if(titleLimit<idx) {
264                    if((csm->options&U_TITLECASE_NO_LOWERCASE)==0) {
265                        /* Normal operation: Lowercase the rest of the word. */
266                        destIndex+=
267                            _caseMap(
268                                csm, ucase_toFullLower,
269                                dest+destIndex, destCapacity-destIndex,
270                                src, &csc,
271                                titleLimit, idx,
272                                pErrorCode);
273                    } else {
274                        /* Optionally just copy the rest of the word unchanged. */
275                        length=idx-titleLimit;
276                        if((destIndex+length)<=destCapacity) {
277                            uprv_memcpy(dest+destIndex, src+titleLimit, length*U_SIZEOF_UCHAR);
278                        }
279                        destIndex+=length;
280                    }
281                }
282            }
283        }
284
285        prev=idx;
286    }
287
288    if(destIndex>destCapacity) {
289        *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
290    }
291    return destIndex;
292}
293
294#endif  // !UCONFIG_NO_BREAK_ITERATION
295
296/* functions available in the common library (for unistr_case.cpp) */
297
298U_CFUNC int32_t U_CALLCONV
299ustrcase_internalToLower(const UCaseMap *csm,
300                         UChar *dest, int32_t destCapacity,
301                         const UChar *src, int32_t srcLength,
302                         UErrorCode *pErrorCode) {
303    UCaseContext csc=UCASECONTEXT_INITIALIZER;
304    csc.p=(void *)src;
305    csc.limit=srcLength;
306    return _caseMap(
307        csm, ucase_toFullLower,
308        dest, destCapacity,
309        src, &csc, 0, srcLength,
310        pErrorCode);
311}
312
313U_CFUNC int32_t U_CALLCONV
314ustrcase_internalToUpper(const UCaseMap *csm,
315                         UChar *dest, int32_t destCapacity,
316                         const UChar *src, int32_t srcLength,
317                         UErrorCode *pErrorCode) {
318    UCaseContext csc=UCASECONTEXT_INITIALIZER;
319    csc.p=(void *)src;
320    csc.limit=srcLength;
321    return _caseMap(
322        csm, ucase_toFullUpper,
323        dest, destCapacity,
324        src, &csc, 0, srcLength,
325        pErrorCode);
326}
327
328static int32_t
329ustr_foldCase(const UCaseProps *csp,
330              UChar *dest, int32_t destCapacity,
331              const UChar *src, int32_t srcLength,
332              uint32_t options,
333              UErrorCode *pErrorCode) {
334    int32_t srcIndex, destIndex;
335
336    const UChar *s;
337    UChar32 c, c2 = 0;
338
339    /* case mapping loop */
340    srcIndex=destIndex=0;
341    while(srcIndex<srcLength) {
342        U16_NEXT(src, srcIndex, srcLength, c);
343        c=ucase_toFullFolding(csp, c, &s, options);
344        if((destIndex<destCapacity) && (c<0 ? (c2=~c)<=0xffff : UCASE_MAX_STRING_LENGTH<c && (c2=c)<=0xffff)) {
345            /* fast path version of appendResult() for BMP results */
346            dest[destIndex++]=(UChar)c2;
347        } else {
348            destIndex=appendResult(dest, destIndex, destCapacity, c, s);
349        }
350    }
351
352    if(destIndex>destCapacity) {
353        *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
354    }
355    return destIndex;
356}
357
358U_CFUNC int32_t U_CALLCONV
359ustrcase_internalFold(const UCaseMap *csm,
360                      UChar *dest, int32_t destCapacity,
361                      const UChar *src, int32_t srcLength,
362                      UErrorCode *pErrorCode) {
363    return ustr_foldCase(csm->csp, dest, destCapacity, src, srcLength, csm->options, pErrorCode);
364}
365
366U_CFUNC int32_t
367ustrcase_map(const UCaseMap *csm,
368             UChar *dest, int32_t destCapacity,
369             const UChar *src, int32_t srcLength,
370             UStringCaseMapper *stringCaseMapper,
371             UErrorCode *pErrorCode) {
372    UChar buffer[300];
373    UChar *temp;
374
375    int32_t destLength;
376
377    /* check argument values */
378    if(U_FAILURE(*pErrorCode)) {
379        return 0;
380    }
381    if( destCapacity<0 ||
382        (dest==NULL && destCapacity>0) ||
383        src==NULL ||
384        srcLength<-1
385    ) {
386        *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
387        return 0;
388    }
389
390    /* get the string length */
391    if(srcLength==-1) {
392        srcLength=u_strlen(src);
393    }
394
395    /* check for overlapping source and destination */
396    if( dest!=NULL &&
397        ((src>=dest && src<(dest+destCapacity)) ||
398         (dest>=src && dest<(src+srcLength)))
399    ) {
400        /* overlap: provide a temporary destination buffer and later copy the result */
401        if(destCapacity<=UPRV_LENGTHOF(buffer)) {
402            /* the stack buffer is large enough */
403            temp=buffer;
404        } else {
405            /* allocate a buffer */
406            temp=(UChar *)uprv_malloc(destCapacity*U_SIZEOF_UCHAR);
407            if(temp==NULL) {
408                *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
409                return 0;
410            }
411        }
412    } else {
413        temp=dest;
414    }
415
416    destLength=stringCaseMapper(csm, temp, destCapacity, src, srcLength, pErrorCode);
417    if(temp!=dest) {
418        /* copy the result string to the destination buffer */
419        if(destLength>0) {
420            int32_t copyLength= destLength<=destCapacity ? destLength : destCapacity;
421            if(copyLength>0) {
422                uprv_memmove(dest, temp, copyLength*U_SIZEOF_UCHAR);
423            }
424        }
425        if(temp!=buffer) {
426            uprv_free(temp);
427        }
428    }
429
430    return u_terminateUChars(dest, destCapacity, destLength, pErrorCode);
431}
432
433/* public API functions */
434
435U_CAPI int32_t U_EXPORT2
436u_strFoldCase(UChar *dest, int32_t destCapacity,
437              const UChar *src, int32_t srcLength,
438              uint32_t options,
439              UErrorCode *pErrorCode) {
440    UCaseMap csm=UCASEMAP_INITIALIZER;
441    csm.csp=ucase_getSingleton();
442    csm.options=options;
443    return ustrcase_map(
444        &csm,
445        dest, destCapacity,
446        src, srcLength,
447        ustrcase_internalFold, pErrorCode);
448}
449
450/* case-insensitive string comparisons -------------------------------------- */
451
452/*
453 * This function is a copy of unorm_cmpEquivFold() minus the parts for
454 * canonical equivalence.
455 * Keep the functions in sync, and see there for how this works.
456 * The duplication is for modularization:
457 * It makes caseless (but not canonical caseless) matches independent of
458 * the normalization code.
459 */
460
461/* stack element for previous-level source/decomposition pointers */
462struct CmpEquivLevel {
463    const UChar *start, *s, *limit;
464};
465typedef struct CmpEquivLevel CmpEquivLevel;
466
467/**
468 * Internal implementation code comparing string with case fold.
469 * This function is called from u_strcmpFold() and u_caseInsensitivePrefixMatch().
470 *
471 * @param s1            input string 1
472 * @param length1       length of string 1, or -1 (NULL terminated)
473 * @param s2            input string 2
474 * @param length2       length of string 2, or -1 (NULL terminated)
475 * @param options       compare options
476 * @param matchLen1     (output) length of partial prefix match in s1
477 * @param matchLen2     (output) length of partial prefix match in s2
478 * @param pErrorCode    receives error status
479 * @return The result of comparison
480 */
481static int32_t _cmpFold(
482            const UChar *s1, int32_t length1,
483            const UChar *s2, int32_t length2,
484            uint32_t options,
485            int32_t *matchLen1, int32_t *matchLen2,
486            UErrorCode *pErrorCode) {
487    int32_t cmpRes = 0;
488
489    const UCaseProps *csp;
490
491    /* current-level start/limit - s1/s2 as current */
492    const UChar *start1, *start2, *limit1, *limit2;
493
494    /* points to the original start address */
495    const UChar *org1, *org2;
496
497    /* points to the end of match + 1 */
498    const UChar *m1, *m2;
499
500    /* case folding variables */
501    const UChar *p;
502    int32_t length;
503
504    /* stacks of previous-level start/current/limit */
505    CmpEquivLevel stack1[2], stack2[2];
506
507    /* case folding buffers, only use current-level start/limit */
508    UChar fold1[UCASE_MAX_STRING_LENGTH+1], fold2[UCASE_MAX_STRING_LENGTH+1];
509
510    /* track which is the current level per string */
511    int32_t level1, level2;
512
513    /* current code units, and code points for lookups */
514    UChar32 c1, c2, cp1, cp2;
515
516    /* no argument error checking because this itself is not an API */
517
518    /*
519     * assume that at least the option U_COMPARE_IGNORE_CASE is set
520     * otherwise this function would have to behave exactly as uprv_strCompare()
521     */
522    csp=ucase_getSingleton();
523    if(U_FAILURE(*pErrorCode)) {
524        return 0;
525    }
526
527    /* initialize */
528    if(matchLen1) {
529        U_ASSERT(matchLen2 !=NULL);
530        *matchLen1=0;
531        *matchLen2=0;
532    }
533
534    start1=m1=org1=s1;
535    if(length1==-1) {
536        limit1=NULL;
537    } else {
538        limit1=s1+length1;
539    }
540
541    start2=m2=org2=s2;
542    if(length2==-1) {
543        limit2=NULL;
544    } else {
545        limit2=s2+length2;
546    }
547
548    level1=level2=0;
549    c1=c2=-1;
550
551    /* comparison loop */
552    for(;;) {
553        /*
554         * here a code unit value of -1 means "get another code unit"
555         * below it will mean "this source is finished"
556         */
557
558        if(c1<0) {
559            /* get next code unit from string 1, post-increment */
560            for(;;) {
561                if(s1==limit1 || ((c1=*s1)==0 && (limit1==NULL || (options&_STRNCMP_STYLE)))) {
562                    if(level1==0) {
563                        c1=-1;
564                        break;
565                    }
566                } else {
567                    ++s1;
568                    break;
569                }
570
571                /* reached end of level buffer, pop one level */
572                do {
573                    --level1;
574                    start1=stack1[level1].start;    /*Not uninitialized*/
575                } while(start1==NULL);
576                s1=stack1[level1].s;                /*Not uninitialized*/
577                limit1=stack1[level1].limit;        /*Not uninitialized*/
578            }
579        }
580
581        if(c2<0) {
582            /* get next code unit from string 2, post-increment */
583            for(;;) {
584                if(s2==limit2 || ((c2=*s2)==0 && (limit2==NULL || (options&_STRNCMP_STYLE)))) {
585                    if(level2==0) {
586                        c2=-1;
587                        break;
588                    }
589                } else {
590                    ++s2;
591                    break;
592                }
593
594                /* reached end of level buffer, pop one level */
595                do {
596                    --level2;
597                    start2=stack2[level2].start;    /*Not uninitialized*/
598                } while(start2==NULL);
599                s2=stack2[level2].s;                /*Not uninitialized*/
600                limit2=stack2[level2].limit;        /*Not uninitialized*/
601            }
602        }
603
604        /*
605         * compare c1 and c2
606         * either variable c1, c2 is -1 only if the corresponding string is finished
607         */
608        if(c1==c2) {
609            const UChar *next1, *next2;
610
611            if(c1<0) {
612                cmpRes=0;   /* c1==c2==-1 indicating end of strings */
613                break;
614            }
615
616            /*
617             * Note: Move the match positions in both strings at the same time
618             *      only when corresponding code point(s) in the original strings
619             *      are fully consumed. For example, when comparing s1="Fust" and
620             *      s2="Fu\u00dfball", s2[2] is folded into "ss", and s1[2] matches
621             *      the first code point in the case-folded data. But the second "s"
622             *      has no matching code point in s1, so this implementation returns
623             *      2 as the prefix match length ("Fu").
624             */
625            next1=next2=NULL;
626            if(level1==0) {
627                next1=s1;
628            } else if(s1==limit1) {
629                /* Note: This implementation only use a single level of stack.
630                 *      If this code needs to be changed to use multiple levels
631                 *      of stacks, the code above should check if the current
632                 *      code is at the end of all stacks.
633                 */
634                U_ASSERT(level1==1);
635
636                /* is s1 at the end of the current stack? */
637                next1=stack1[0].s;
638            }
639
640            if (next1!=NULL) {
641                if(level2==0) {
642                    next2=s2;
643                } else if(s2==limit2) {
644                    U_ASSERT(level2==1);
645
646                    /* is s2 at the end of the current stack? */
647                    next2=stack2[0].s;
648                }
649                if(next2!=NULL) {
650                    m1=next1;
651                    m2=next2;
652                }
653            }
654            c1=c2=-1;       /* make us fetch new code units */
655            continue;
656        } else if(c1<0) {
657            cmpRes=-1;      /* string 1 ends before string 2 */
658            break;
659        } else if(c2<0) {
660            cmpRes=1;       /* string 2 ends before string 1 */
661            break;
662        }
663        /* c1!=c2 && c1>=0 && c2>=0 */
664
665        /* get complete code points for c1, c2 for lookups if either is a surrogate */
666        cp1=c1;
667        if(U_IS_SURROGATE(c1)) {
668            UChar c;
669
670            if(U_IS_SURROGATE_LEAD(c1)) {
671                if(s1!=limit1 && U16_IS_TRAIL(c=*s1)) {
672                    /* advance ++s1; only below if cp1 decomposes/case-folds */
673                    cp1=U16_GET_SUPPLEMENTARY(c1, c);
674                }
675            } else /* isTrail(c1) */ {
676                if(start1<=(s1-2) && U16_IS_LEAD(c=*(s1-2))) {
677                    cp1=U16_GET_SUPPLEMENTARY(c, c1);
678                }
679            }
680        }
681
682        cp2=c2;
683        if(U_IS_SURROGATE(c2)) {
684            UChar c;
685
686            if(U_IS_SURROGATE_LEAD(c2)) {
687                if(s2!=limit2 && U16_IS_TRAIL(c=*s2)) {
688                    /* advance ++s2; only below if cp2 decomposes/case-folds */
689                    cp2=U16_GET_SUPPLEMENTARY(c2, c);
690                }
691            } else /* isTrail(c2) */ {
692                if(start2<=(s2-2) && U16_IS_LEAD(c=*(s2-2))) {
693                    cp2=U16_GET_SUPPLEMENTARY(c, c2);
694                }
695            }
696        }
697
698        /*
699         * go down one level for each string
700         * continue with the main loop as soon as there is a real change
701         */
702
703        if( level1==0 &&
704            (length=ucase_toFullFolding(csp, (UChar32)cp1, &p, options))>=0
705        ) {
706            /* cp1 case-folds to the code point "length" or to p[length] */
707            if(U_IS_SURROGATE(c1)) {
708                if(U_IS_SURROGATE_LEAD(c1)) {
709                    /* advance beyond source surrogate pair if it case-folds */
710                    ++s1;
711                } else /* isTrail(c1) */ {
712                    /*
713                     * we got a supplementary code point when hitting its trail surrogate,
714                     * therefore the lead surrogate must have been the same as in the other string;
715                     * compare this decomposition with the lead surrogate in the other string
716                     * remember that this simulates bulk text replacement:
717                     * the decomposition would replace the entire code point
718                     */
719                    --s2;
720                    --m2;
721                    c2=*(s2-1);
722                }
723            }
724
725            /* push current level pointers */
726            stack1[0].start=start1;
727            stack1[0].s=s1;
728            stack1[0].limit=limit1;
729            ++level1;
730
731            /* copy the folding result to fold1[] */
732            if(length<=UCASE_MAX_STRING_LENGTH) {
733                u_memcpy(fold1, p, length);
734            } else {
735                int32_t i=0;
736                U16_APPEND_UNSAFE(fold1, i, length);
737                length=i;
738            }
739
740            /* set next level pointers to case folding */
741            start1=s1=fold1;
742            limit1=fold1+length;
743
744            /* get ready to read from decomposition, continue with loop */
745            c1=-1;
746            continue;
747        }
748
749        if( level2==0 &&
750            (length=ucase_toFullFolding(csp, (UChar32)cp2, &p, options))>=0
751        ) {
752            /* cp2 case-folds to the code point "length" or to p[length] */
753            if(U_IS_SURROGATE(c2)) {
754                if(U_IS_SURROGATE_LEAD(c2)) {
755                    /* advance beyond source surrogate pair if it case-folds */
756                    ++s2;
757                } else /* isTrail(c2) */ {
758                    /*
759                     * we got a supplementary code point when hitting its trail surrogate,
760                     * therefore the lead surrogate must have been the same as in the other string;
761                     * compare this decomposition with the lead surrogate in the other string
762                     * remember that this simulates bulk text replacement:
763                     * the decomposition would replace the entire code point
764                     */
765                    --s1;
766                    --m2;
767                    c1=*(s1-1);
768                }
769            }
770
771            /* push current level pointers */
772            stack2[0].start=start2;
773            stack2[0].s=s2;
774            stack2[0].limit=limit2;
775            ++level2;
776
777            /* copy the folding result to fold2[] */
778            if(length<=UCASE_MAX_STRING_LENGTH) {
779                u_memcpy(fold2, p, length);
780            } else {
781                int32_t i=0;
782                U16_APPEND_UNSAFE(fold2, i, length);
783                length=i;
784            }
785
786            /* set next level pointers to case folding */
787            start2=s2=fold2;
788            limit2=fold2+length;
789
790            /* get ready to read from decomposition, continue with loop */
791            c2=-1;
792            continue;
793        }
794
795        /*
796         * no decomposition/case folding, max level for both sides:
797         * return difference result
798         *
799         * code point order comparison must not just return cp1-cp2
800         * because when single surrogates are present then the surrogate pairs
801         * that formed cp1 and cp2 may be from different string indexes
802         *
803         * example: { d800 d800 dc01 } vs. { d800 dc00 }, compare at second code units
804         * c1=d800 cp1=10001 c2=dc00 cp2=10000
805         * cp1-cp2>0 but c1-c2<0 and in fact in UTF-32 it is { d800 10001 } < { 10000 }
806         *
807         * therefore, use same fix-up as in ustring.c/uprv_strCompare()
808         * except: uprv_strCompare() fetches c=*s while this functions fetches c=*s++
809         * so we have slightly different pointer/start/limit comparisons here
810         */
811
812        if(c1>=0xd800 && c2>=0xd800 && (options&U_COMPARE_CODE_POINT_ORDER)) {
813            /* subtract 0x2800 from BMP code points to make them smaller than supplementary ones */
814            if(
815                (c1<=0xdbff && s1!=limit1 && U16_IS_TRAIL(*s1)) ||
816                (U16_IS_TRAIL(c1) && start1!=(s1-1) && U16_IS_LEAD(*(s1-2)))
817            ) {
818                /* part of a surrogate pair, leave >=d800 */
819            } else {
820                /* BMP code point - may be surrogate code point - make <d800 */
821                c1-=0x2800;
822            }
823
824            if(
825                (c2<=0xdbff && s2!=limit2 && U16_IS_TRAIL(*s2)) ||
826                (U16_IS_TRAIL(c2) && start2!=(s2-1) && U16_IS_LEAD(*(s2-2)))
827            ) {
828                /* part of a surrogate pair, leave >=d800 */
829            } else {
830                /* BMP code point - may be surrogate code point - make <d800 */
831                c2-=0x2800;
832            }
833        }
834
835        cmpRes=c1-c2;
836        break;
837    }
838
839    if(matchLen1) {
840        *matchLen1=m1-org1;
841        *matchLen2=m2-org2;
842    }
843    return cmpRes;
844}
845
846/* internal function */
847U_CFUNC int32_t
848u_strcmpFold(const UChar *s1, int32_t length1,
849             const UChar *s2, int32_t length2,
850             uint32_t options,
851             UErrorCode *pErrorCode) {
852    return _cmpFold(s1, length1, s2, length2, options, NULL, NULL, pErrorCode);
853}
854
855/* public API functions */
856
857U_CAPI int32_t U_EXPORT2
858u_strCaseCompare(const UChar *s1, int32_t length1,
859                 const UChar *s2, int32_t length2,
860                 uint32_t options,
861                 UErrorCode *pErrorCode) {
862    /* argument checking */
863    if(pErrorCode==0 || U_FAILURE(*pErrorCode)) {
864        return 0;
865    }
866    if(s1==NULL || length1<-1 || s2==NULL || length2<-1) {
867        *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
868        return 0;
869    }
870    return u_strcmpFold(s1, length1, s2, length2,
871                        options|U_COMPARE_IGNORE_CASE,
872                        pErrorCode);
873}
874
875U_CAPI int32_t U_EXPORT2
876u_strcasecmp(const UChar *s1, const UChar *s2, uint32_t options) {
877    UErrorCode errorCode=U_ZERO_ERROR;
878    return u_strcmpFold(s1, -1, s2, -1,
879                        options|U_COMPARE_IGNORE_CASE,
880                        &errorCode);
881}
882
883U_CAPI int32_t U_EXPORT2
884u_memcasecmp(const UChar *s1, const UChar *s2, int32_t length, uint32_t options) {
885    UErrorCode errorCode=U_ZERO_ERROR;
886    return u_strcmpFold(s1, length, s2, length,
887                        options|U_COMPARE_IGNORE_CASE,
888                        &errorCode);
889}
890
891U_CAPI int32_t U_EXPORT2
892u_strncasecmp(const UChar *s1, const UChar *s2, int32_t n, uint32_t options) {
893    UErrorCode errorCode=U_ZERO_ERROR;
894    return u_strcmpFold(s1, n, s2, n,
895                        options|(U_COMPARE_IGNORE_CASE|_STRNCMP_STYLE),
896                        &errorCode);
897}
898
899/* internal API - detect length of shared prefix */
900U_CAPI void
901u_caseInsensitivePrefixMatch(const UChar *s1, int32_t length1,
902                             const UChar *s2, int32_t length2,
903                             uint32_t options,
904                             int32_t *matchLen1, int32_t *matchLen2,
905                             UErrorCode *pErrorCode) {
906    _cmpFold(s1, length1, s2, length2, options,
907        matchLen1, matchLen2, pErrorCode);
908}
909