The Tor Browser: intl/icu/source/common/ustrcase.cpp@fc2d59ddac77 (annotated)

intl/icu/source/common/ustrcase.cpp@fc2d59ddac77 (annotated)

intl/icu/source/common/ustrcase.cpp

Wed, 31 Dec 2014 07:22:50 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 07:22:50 +0100
branch: TOR_BUG_3246
changeset 4: fc2d59ddac77
permissions: -rw-r--r--

Correct previous dual key logic pending first delivery installment.

 /*
 *******************************************************************************
 *
 *   Copyright (C) 2001-2011, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 *******************************************************************************
 *   file name:  ustrcase.cpp
 *   encoding:   US-ASCII
 *   tab size:   8 (not used)
 *   indentation:4
 *
 *   created on: 2002feb20
 *   created by: Markus W. Scherer
 *
 *   Implementation file for string casing C API functions.
 *   Uses functions from uchar.c for basic functionality that requires access
 *   to the Unicode Character Database (uprops.dat).
 */
 #include "unicode/utypes.h"
 #include "unicode/brkiter.h"
 #include "unicode/ustring.h"
 #include "unicode/ucasemap.h"
 #include "unicode/ubrk.h"
 #include "unicode/utf.h"
 #include "unicode/utf16.h"
 #include "cmemory.h"
 #include "ucase.h"
 #include "ustr_imp.h"
 #define LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0]))
 U_NAMESPACE_USE
 /* string casing ------------------------------------------------------------ */
 /* Appends a full case mapping result, see UCASE_MAX_STRING_LENGTH. */
 static inline int32_t
 appendResult(UChar *dest, int32_t destIndex, int32_t destCapacity,
              int32_t result, const UChar *s) {
     UChar32 c;
     int32_t length;
     /* decode the result */
     if(result<0) {
         /* (not) original code point */
         c=~result;
         length=-1;
     } else if(result<=UCASE_MAX_STRING_LENGTH) {
         c=U_SENTINEL;
         length=result;
     } else {
         c=result;
         length=-1;
     }
     if(destIndex<destCapacity) {
         /* append the result */
         if(length<0) {
             /* code point */
             UBool isError=FALSE;
             U16_APPEND(dest, destIndex, destCapacity, c, isError);
             if(isError) {
                 /* overflow, nothing written */
                 destIndex+=U16_LENGTH(c);
             }
         } else {
             /* string */
             if((destIndex+length)<=destCapacity) {
                 while(length>0) {
                     dest[destIndex++]=*s++;
                     --length;
                 }
             } else {
                 /* overflow */
                 destIndex+=length;
             }
         }
     } else {
         /* preflight */
         if(length<0) {
             destIndex+=U16_LENGTH(c);
         } else {
             destIndex+=length;
         }
     }
     return destIndex;
 }
 static UChar32 U_CALLCONV
 utf16_caseContextIterator(void *context, int8_t dir) {
     UCaseContext *csc=(UCaseContext *)context;
     UChar32 c;
     if(dir<0) {
         /* reset for backward iteration */
         csc->index=csc->cpStart;
         csc->dir=dir;
     } else if(dir>0) {
         /* reset for forward iteration */
         csc->index=csc->cpLimit;
         csc->dir=dir;
     } else {
         /* continue current iteration direction */
         dir=csc->dir;
     }
     if(dir<0) {
         if(csc->start<csc->index) {
             U16_PREV((const UChar *)csc->p, csc->start, csc->index, c);
             return c;
         }
     } else {
         if(csc->index<csc->limit) {
             U16_NEXT((const UChar *)csc->p, csc->index, csc->limit, c);
             return c;
         }
     }
     return U_SENTINEL;
 }
 /*
  * Case-maps [srcStart..srcLimit[ but takes
  * context [0..srcLength[ into account.
  */
 static int32_t
 _caseMap(const UCaseMap *csm, UCaseMapFull *map,
          UChar *dest, int32_t destCapacity,
          const UChar *src, UCaseContext *csc,
          int32_t srcStart, int32_t srcLimit,
          UErrorCode *pErrorCode) {
     const UChar *s;
     UChar32 c, c2 = 0;
     int32_t srcIndex, destIndex;
     int32_t locCache;
     locCache=csm->locCache;
     /* case mapping loop */
     srcIndex=srcStart;
     destIndex=0;
     while(srcIndex<srcLimit) {
         csc->cpStart=srcIndex;
         U16_NEXT(src, srcIndex, srcLimit, c);
         csc->cpLimit=srcIndex;
         c=map(csm->csp, c, utf16_caseContextIterator, csc, &s, csm->locale, &locCache);
         if((destIndex<destCapacity) && (c<0 ? (c2=~c)<=0xffff : UCASE_MAX_STRING_LENGTH<c && (c2=c)<=0xffff)) {
             /* fast path version of appendResult() for BMP results */
             dest[destIndex++]=(UChar)c2;
         } else {
             destIndex=appendResult(dest, destIndex, destCapacity, c, s);
         }
     }
     if(destIndex>destCapacity) {
         *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
     }
     return destIndex;
 }
 #if !UCONFIG_NO_BREAK_ITERATION
 U_CFUNC int32_t U_CALLCONV
 ustrcase_internalToTitle(const UCaseMap *csm,
                          UChar *dest, int32_t destCapacity,
                          const UChar *src, int32_t srcLength,
                          UErrorCode *pErrorCode) {
     const UChar *s;
     UChar32 c;
     int32_t prev, titleStart, titleLimit, idx, destIndex, length;
     UBool isFirstIndex;
     if(U_FAILURE(*pErrorCode)) {
         return 0;
     }
     // Use the C++ abstract base class to minimize dependencies.
     // TODO: Change UCaseMap.iter to store a BreakIterator directly.
     BreakIterator *bi=reinterpret_cast<BreakIterator *>(csm->iter);
     /* set up local variables */
     int32_t locCache=csm->locCache;
     UCaseContext csc=UCASECONTEXT_INITIALIZER;
     csc.p=(void *)src;
     csc.limit=srcLength;
     destIndex=0;
     prev=0;
     isFirstIndex=TRUE;
     /* titlecasing loop */
     while(prev<srcLength) {
         /* find next index where to titlecase */
         if(isFirstIndex) {
             isFirstIndex=FALSE;
             idx=bi->first();
         } else {
             idx=bi->next();
         }
         if(idx==UBRK_DONE || idx>srcLength) {
             idx=srcLength;
         }
         /*
          * Unicode 4 & 5 section 3.13 Default Case Operations:
          *
          * R3  toTitlecase(X): Find the word boundaries based on Unicode Standard Annex
          * #29, "Text Boundaries." Between each pair of word boundaries, find the first
          * cased character F. If F exists, map F to default_title(F); then map each
          * subsequent character C to default_lower(C).
          *
          * In this implementation, segment [prev..index[ into 3 parts:
          * a) uncased characters (copy as-is) [prev..titleStart[
          * b) first case letter (titlecase)         [titleStart..titleLimit[
          * c) subsequent characters (lowercase)                 [titleLimit..index[
          */
         if(prev<idx) {
             /* find and copy uncased characters [prev..titleStart[ */
             titleStart=titleLimit=prev;
             U16_NEXT(src, titleLimit, idx, c);
             if((csm->options&U_TITLECASE_NO_BREAK_ADJUSTMENT)==0 && UCASE_NONE==ucase_getType(csm->csp, c)) {
                 /* Adjust the titlecasing index (titleStart) to the next cased character. */
                 for(;;) {
                     titleStart=titleLimit;
                     if(titleLimit==idx) {
                         /*
                          * only uncased characters in [prev..index[
                          * stop with titleStart==titleLimit==index
                          */
                         break;
                     }
                     U16_NEXT(src, titleLimit, idx, c);
                     if(UCASE_NONE!=ucase_getType(csm->csp, c)) {
                         break; /* cased letter at [titleStart..titleLimit[ */
                     }
                 }
                 length=titleStart-prev;
                 if(length>0) {
                     if((destIndex+length)<=destCapacity) {
                         uprv_memcpy(dest+destIndex, src+prev, length*U_SIZEOF_UCHAR);
                     }
                     destIndex+=length;
                 }
             }
             if(titleStart<titleLimit) {
                 /* titlecase c which is from [titleStart..titleLimit[ */
                 csc.cpStart=titleStart;
                 csc.cpLimit=titleLimit;
                 c=ucase_toFullTitle(csm->csp, c, utf16_caseContextIterator, &csc, &s, csm->locale, &locCache);
                 destIndex=appendResult(dest, destIndex, destCapacity, c, s);
                 /* Special case Dutch IJ titlecasing */
                 if ( titleStart+1 < idx &&
                      ucase_getCaseLocale(csm->locale,&locCache) == UCASE_LOC_DUTCH &&
                      ( src[titleStart] == (UChar32) 0x0049 || src[titleStart] == (UChar32) 0x0069 ) &&
                      ( src[titleStart+1] == (UChar32) 0x004A || src[titleStart+1] == (UChar32) 0x006A )) {
                             c=(UChar32) 0x004A;
                             destIndex=appendResult(dest, destIndex, destCapacity, c, s);
                             titleLimit++;
                 }
                 /* lowercase [titleLimit..index[ */
                 if(titleLimit<idx) {
                     if((csm->options&U_TITLECASE_NO_LOWERCASE)==0) {
                         /* Normal operation: Lowercase the rest of the word. */
                         destIndex+=
                             _caseMap(
                                 csm, ucase_toFullLower,
                                 dest+destIndex, destCapacity-destIndex,
                                 src, &csc,
                                 titleLimit, idx,
                                 pErrorCode);
                     } else {
                         /* Optionally just copy the rest of the word unchanged. */
                         length=idx-titleLimit;
                         if((destIndex+length)<=destCapacity) {
                             uprv_memcpy(dest+destIndex, src+titleLimit, length*U_SIZEOF_UCHAR);
                         }
                         destIndex+=length;
                     }
                 }
             }
         }
         prev=idx;
     }
     if(destIndex>destCapacity) {
         *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
     }
     return destIndex;
 }
 #endif  // !UCONFIG_NO_BREAK_ITERATION
 /* functions available in the common library (for unistr_case.cpp) */
 U_CFUNC int32_t U_CALLCONV
 ustrcase_internalToLower(const UCaseMap *csm,
                          UChar *dest, int32_t destCapacity,
                          const UChar *src, int32_t srcLength,
                          UErrorCode *pErrorCode) {
     UCaseContext csc=UCASECONTEXT_INITIALIZER;
     csc.p=(void *)src;
     csc.limit=srcLength;
     return _caseMap(
         csm, ucase_toFullLower,
         dest, destCapacity,
         src, &csc, 0, srcLength,
         pErrorCode);
 }
 U_CFUNC int32_t U_CALLCONV
 ustrcase_internalToUpper(const UCaseMap *csm,
                          UChar *dest, int32_t destCapacity,
                          const UChar *src, int32_t srcLength,
                          UErrorCode *pErrorCode) {
     UCaseContext csc=UCASECONTEXT_INITIALIZER;
     csc.p=(void *)src;
     csc.limit=srcLength;
     return _caseMap(
         csm, ucase_toFullUpper,
         dest, destCapacity,
         src, &csc, 0, srcLength,
         pErrorCode);
 }
 static int32_t
 ustr_foldCase(const UCaseProps *csp,
               UChar *dest, int32_t destCapacity,
               const UChar *src, int32_t srcLength,
               uint32_t options,
               UErrorCode *pErrorCode) {
     int32_t srcIndex, destIndex;
     const UChar *s;
     UChar32 c, c2 = 0;
     /* case mapping loop */
     srcIndex=destIndex=0;
     while(srcIndex<srcLength) {
         U16_NEXT(src, srcIndex, srcLength, c);
         c=ucase_toFullFolding(csp, c, &s, options);
         if((destIndex<destCapacity) && (c<0 ? (c2=~c)<=0xffff : UCASE_MAX_STRING_LENGTH<c && (c2=c)<=0xffff)) {
             /* fast path version of appendResult() for BMP results */
             dest[destIndex++]=(UChar)c2;
         } else {
             destIndex=appendResult(dest, destIndex, destCapacity, c, s);
         }
     }
     if(destIndex>destCapacity) {
         *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
     }
     return destIndex;
 }
 U_CFUNC int32_t U_CALLCONV
 ustrcase_internalFold(const UCaseMap *csm,
                       UChar *dest, int32_t destCapacity,
                       const UChar *src, int32_t srcLength,
                       UErrorCode *pErrorCode) {
     return ustr_foldCase(csm->csp, dest, destCapacity, src, srcLength, csm->options, pErrorCode);
 }
 U_CFUNC int32_t
 ustrcase_map(const UCaseMap *csm,
              UChar *dest, int32_t destCapacity,
              const UChar *src, int32_t srcLength,
              UStringCaseMapper *stringCaseMapper,
              UErrorCode *pErrorCode) {
     UChar buffer[300];
     UChar *temp;
     int32_t destLength;
     /* check argument values */
     if(U_FAILURE(*pErrorCode)) {
         return 0;
     }
     if( destCapacity<0 ||
         (dest==NULL && destCapacity>0) ||
         src==NULL ||
         srcLength<-1
     ) {
         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
         return 0;
     }
     /* get the string length */
     if(srcLength==-1) {
         srcLength=u_strlen(src);
     }
     /* check for overlapping source and destination */
     if( dest!=NULL &&
         ((src>=dest && src<(dest+destCapacity)) ||
          (dest>=src && dest<(src+srcLength)))
     ) {
         /* overlap: provide a temporary destination buffer and later copy the result */
         if(destCapacity<=LENGTHOF(buffer)) {
             /* the stack buffer is large enough */
             temp=buffer;
         } else {
             /* allocate a buffer */
             temp=(UChar *)uprv_malloc(destCapacity*U_SIZEOF_UCHAR);
             if(temp==NULL) {
                 *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
                 return 0;
             }
         }
     } else {
         temp=dest;
     }
     destLength=stringCaseMapper(csm, temp, destCapacity, src, srcLength, pErrorCode);
     if(temp!=dest) {
         /* copy the result string to the destination buffer */
         if(destLength>0) {
             int32_t copyLength= destLength<=destCapacity ? destLength : destCapacity;
             if(copyLength>0) {
                 uprv_memmove(dest, temp, copyLength*U_SIZEOF_UCHAR);
             }
         }
         if(temp!=buffer) {
             uprv_free(temp);
         }
     }
     return u_terminateUChars(dest, destCapacity, destLength, pErrorCode);
 }
 /* public API functions */
 U_CAPI int32_t U_EXPORT2
 u_strFoldCase(UChar *dest, int32_t destCapacity,
               const UChar *src, int32_t srcLength,
               uint32_t options,
               UErrorCode *pErrorCode) {
     UCaseMap csm=UCASEMAP_INITIALIZER;
     csm.csp=ucase_getSingleton();
     csm.options=options;
     return ustrcase_map(
         &csm,
         dest, destCapacity,
         src, srcLength,
         ustrcase_internalFold, pErrorCode);
 }
 /* case-insensitive string comparisons -------------------------------------- */
 /*
  * This function is a copy of unorm_cmpEquivFold() minus the parts for
  * canonical equivalence.
  * Keep the functions in sync, and see there for how this works.
  * The duplication is for modularization:
  * It makes caseless (but not canonical caseless) matches independent of
  * the normalization code.
  */
 /* stack element for previous-level source/decomposition pointers */
 struct CmpEquivLevel {
     const UChar *start, *s, *limit;
 };
 typedef struct CmpEquivLevel CmpEquivLevel;
 /* internal function */
 U_CFUNC int32_t
 u_strcmpFold(const UChar *s1, int32_t length1,
              const UChar *s2, int32_t length2,
              uint32_t options,
              UErrorCode *pErrorCode) {
     const UCaseProps *csp;
     /* current-level start/limit - s1/s2 as current */
     const UChar *start1, *start2, *limit1, *limit2;
     /* case folding variables */
     const UChar *p;
     int32_t length;
     /* stacks of previous-level start/current/limit */
     CmpEquivLevel stack1[2], stack2[2];
     /* case folding buffers, only use current-level start/limit */
     UChar fold1[UCASE_MAX_STRING_LENGTH+1], fold2[UCASE_MAX_STRING_LENGTH+1];
     /* track which is the current level per string */
     int32_t level1, level2;
     /* current code units, and code points for lookups */
     UChar32 c1, c2, cp1, cp2;
     /* no argument error checking because this itself is not an API */
     /*
      * assume that at least the option U_COMPARE_IGNORE_CASE is set
      * otherwise this function would have to behave exactly as uprv_strCompare()
      */
     csp=ucase_getSingleton();
     if(U_FAILURE(*pErrorCode)) {
         return 0;
     }
     /* initialize */
     start1=s1;
     if(length1==-1) {
         limit1=NULL;
     } else {
         limit1=s1+length1;
     }
     start2=s2;
     if(length2==-1) {
         limit2=NULL;
     } else {
         limit2=s2+length2;
     }
     level1=level2=0;
     c1=c2=-1;
     /* comparison loop */
     for(;;) {
         /*
          * here a code unit value of -1 means "get another code unit"
          * below it will mean "this source is finished"
          */
         if(c1<0) {
             /* get next code unit from string 1, post-increment */
             for(;;) {
                 if(s1==limit1 || ((c1=*s1)==0 && (limit1==NULL || (options&_STRNCMP_STYLE)))) {
                     if(level1==0) {
                         c1=-1;
                         break;
                     }
                 } else {
                     ++s1;
                     break;
                 }
                 /* reached end of level buffer, pop one level */
                 do {
                     --level1;
                     start1=stack1[level1].start;    /*Not uninitialized*/
                 } while(start1==NULL);
                 s1=stack1[level1].s;                /*Not uninitialized*/
                 limit1=stack1[level1].limit;        /*Not uninitialized*/
             }
         }
         if(c2<0) {
             /* get next code unit from string 2, post-increment */
             for(;;) {
                 if(s2==limit2 || ((c2=*s2)==0 && (limit2==NULL || (options&_STRNCMP_STYLE)))) {
                     if(level2==0) {
                         c2=-1;
                         break;
                     }
                 } else {
                     ++s2;
                     break;
                 }
                 /* reached end of level buffer, pop one level */
                 do {
                     --level2;
                     start2=stack2[level2].start;    /*Not uninitialized*/
                 } while(start2==NULL);
                 s2=stack2[level2].s;                /*Not uninitialized*/
                 limit2=stack2[level2].limit;        /*Not uninitialized*/
             }
         }
         /*
          * compare c1 and c2
          * either variable c1, c2 is -1 only if the corresponding string is finished
          */
         if(c1==c2) {
             if(c1<0) {
                 return 0;   /* c1==c2==-1 indicating end of strings */
             }
             c1=c2=-1;       /* make us fetch new code units */
             continue;
         } else if(c1<0) {
             return -1;      /* string 1 ends before string 2 */
         } else if(c2<0) {
             return 1;       /* string 2 ends before string 1 */
         }
         /* c1!=c2 && c1>=0 && c2>=0 */
         /* get complete code points for c1, c2 for lookups if either is a surrogate */
         cp1=c1;
         if(U_IS_SURROGATE(c1)) {
             UChar c;
             if(U_IS_SURROGATE_LEAD(c1)) {
                 if(s1!=limit1 && U16_IS_TRAIL(c=*s1)) {
                     /* advance ++s1; only below if cp1 decomposes/case-folds */
                     cp1=U16_GET_SUPPLEMENTARY(c1, c);
                 }
             } else /* isTrail(c1) */ {
                 if(start1<=(s1-2) && U16_IS_LEAD(c=*(s1-2))) {
                     cp1=U16_GET_SUPPLEMENTARY(c, c1);
                 }
             }
         }
         cp2=c2;
         if(U_IS_SURROGATE(c2)) {
             UChar c;
             if(U_IS_SURROGATE_LEAD(c2)) {
                 if(s2!=limit2 && U16_IS_TRAIL(c=*s2)) {
                     /* advance ++s2; only below if cp2 decomposes/case-folds */
                     cp2=U16_GET_SUPPLEMENTARY(c2, c);
                 }
             } else /* isTrail(c2) */ {
                 if(start2<=(s2-2) && U16_IS_LEAD(c=*(s2-2))) {
                     cp2=U16_GET_SUPPLEMENTARY(c, c2);
                 }
             }
         }
         /*
          * go down one level for each string
          * continue with the main loop as soon as there is a real change
          */
         if( level1==0 &&
             (length=ucase_toFullFolding(csp, (UChar32)cp1, &p, options))>=0
         ) {
             /* cp1 case-folds to the code point "length" or to p[length] */
             if(U_IS_SURROGATE(c1)) {
                 if(U_IS_SURROGATE_LEAD(c1)) {
                     /* advance beyond source surrogate pair if it case-folds */
                     ++s1;
                 } else /* isTrail(c1) */ {
                     /*
                      * we got a supplementary code point when hitting its trail surrogate,
                      * therefore the lead surrogate must have been the same as in the other string;
                      * compare this decomposition with the lead surrogate in the other string
                      * remember that this simulates bulk text replacement:
                      * the decomposition would replace the entire code point
                      */
                     --s2;
                     c2=*(s2-1);
                 }
             }
             /* push current level pointers */
             stack1[0].start=start1;
             stack1[0].s=s1;
             stack1[0].limit=limit1;
             ++level1;
             /* copy the folding result to fold1[] */
             if(length<=UCASE_MAX_STRING_LENGTH) {
                 u_memcpy(fold1, p, length);
             } else {
                 int32_t i=0;
                 U16_APPEND_UNSAFE(fold1, i, length);
                 length=i;
             }
             /* set next level pointers to case folding */
             start1=s1=fold1;
             limit1=fold1+length;
             /* get ready to read from decomposition, continue with loop */
             c1=-1;
             continue;
         }
         if( level2==0 &&
             (length=ucase_toFullFolding(csp, (UChar32)cp2, &p, options))>=0
         ) {
             /* cp2 case-folds to the code point "length" or to p[length] */
             if(U_IS_SURROGATE(c2)) {
                 if(U_IS_SURROGATE_LEAD(c2)) {
                     /* advance beyond source surrogate pair if it case-folds */
                     ++s2;
                 } else /* isTrail(c2) */ {
                     /*
                      * we got a supplementary code point when hitting its trail surrogate,
                      * therefore the lead surrogate must have been the same as in the other string;
                      * compare this decomposition with the lead surrogate in the other string
                      * remember that this simulates bulk text replacement:
                      * the decomposition would replace the entire code point
                      */
                     --s1;
                     c1=*(s1-1);
                 }
             }
             /* push current level pointers */
             stack2[0].start=start2;
             stack2[0].s=s2;
             stack2[0].limit=limit2;
             ++level2;
             /* copy the folding result to fold2[] */
             if(length<=UCASE_MAX_STRING_LENGTH) {
                 u_memcpy(fold2, p, length);
             } else {
                 int32_t i=0;
                 U16_APPEND_UNSAFE(fold2, i, length);
                 length=i;
             }
             /* set next level pointers to case folding */
             start2=s2=fold2;
             limit2=fold2+length;
             /* get ready to read from decomposition, continue with loop */
             c2=-1;
             continue;
         }
         /*
          * no decomposition/case folding, max level for both sides:
          * return difference result
          *
          * code point order comparison must not just return cp1-cp2
          * because when single surrogates are present then the surrogate pairs
          * that formed cp1 and cp2 may be from different string indexes
          *
          * example: { d800 d800 dc01 } vs. { d800 dc00 }, compare at second code units
          * c1=d800 cp1=10001 c2=dc00 cp2=10000
          * cp1-cp2>0 but c1-c2<0 and in fact in UTF-32 it is { d800 10001 } < { 10000 }
          *
          * therefore, use same fix-up as in ustring.c/uprv_strCompare()
          * except: uprv_strCompare() fetches c=*s while this functions fetches c=*s++
          * so we have slightly different pointer/start/limit comparisons here
          */
         if(c1>=0xd800 && c2>=0xd800 && (options&U_COMPARE_CODE_POINT_ORDER)) {
             /* subtract 0x2800 from BMP code points to make them smaller than supplementary ones */
             if(
                 (c1<=0xdbff && s1!=limit1 && U16_IS_TRAIL(*s1)) ||
                 (U16_IS_TRAIL(c1) && start1!=(s1-1) && U16_IS_LEAD(*(s1-2)))
             ) {
                 /* part of a surrogate pair, leave >=d800 */
             } else {
                 /* BMP code point - may be surrogate code point - make <d800 */
                 c1-=0x2800;
             }
             if(
                 (c2<=0xdbff && s2!=limit2 && U16_IS_TRAIL(*s2)) ||
                 (U16_IS_TRAIL(c2) && start2!=(s2-1) && U16_IS_LEAD(*(s2-2)))
             ) {
                 /* part of a surrogate pair, leave >=d800 */
             } else {
                 /* BMP code point - may be surrogate code point - make <d800 */
                 c2-=0x2800;
             }
         }
         return c1-c2;
     }
 }
 /* public API functions */
 U_CAPI int32_t U_EXPORT2
 u_strCaseCompare(const UChar *s1, int32_t length1,
                  const UChar *s2, int32_t length2,
                  uint32_t options,
                  UErrorCode *pErrorCode) {
     /* argument checking */
     if(pErrorCode==0 || U_FAILURE(*pErrorCode)) {
         return 0;
     }
     if(s1==NULL || length1<-1 || s2==NULL || length2<-1) {
         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
         return 0;
     }
     return u_strcmpFold(s1, length1, s2, length2,
                         options|U_COMPARE_IGNORE_CASE,
                         pErrorCode);
 }
 U_CAPI int32_t U_EXPORT2
 u_strcasecmp(const UChar *s1, const UChar *s2, uint32_t options) {
     UErrorCode errorCode=U_ZERO_ERROR;
     return u_strcmpFold(s1, -1, s2, -1,
                         options|U_COMPARE_IGNORE_CASE,
                         &errorCode);
 }
 U_CAPI int32_t U_EXPORT2
 u_memcasecmp(const UChar *s1, const UChar *s2, int32_t length, uint32_t options) {
     UErrorCode errorCode=U_ZERO_ERROR;
     return u_strcmpFold(s1, length, s2, length,
                         options|U_COMPARE_IGNORE_CASE,
                         &errorCode);
 }
 U_CAPI int32_t U_EXPORT2
 u_strncasecmp(const UChar *s1, const UChar *s2, int32_t n, uint32_t options) {
     UErrorCode errorCode=U_ZERO_ERROR;
     return u_strcmpFold(s1, n, s2, n,
                         options|(U_COMPARE_IGNORE_CASE|_STRNCMP_STYLE),
                         &errorCode);
 }

The Tor Browser / annotate

intl/icu/source/common/ustrcase.cpp@fc2d59ddac77 (annotated)

intl/icu/source/common/ustrcase.cpp