| // © 2016 and later: Unicode, Inc. and others. |
| // License & terms of use: http://www.unicode.org/copyright.html |
| /* |
| ******************************************************************************* |
| * |
| * Copyright (C) 2001-2014, International Business Machines |
| * Corporation and others. All Rights Reserved. |
| * |
| ******************************************************************************* |
| * file name: unormcmp.cpp |
| * encoding: UTF-8 |
| * tab size: 8 (not used) |
| * indentation:4 |
| * |
| * created on: 2004sep13 |
| * created by: Markus W. Scherer |
| * |
| * unorm_compare() function moved here from unorm.cpp for better modularization. |
| * Depends on both normalization and case folding. |
| * Allows unorm.cpp to not depend on any character properties code. |
| */ |
| |
| #include "unicode/utypes.h" |
| |
| #if !UCONFIG_NO_NORMALIZATION |
| |
| #include "unicode/unorm.h" |
| #include "unicode/ustring.h" |
| #include "cmemory.h" |
| #include "normalizer2impl.h" |
| #include "ucase.h" |
| #include "uprops.h" |
| #include "ustr_imp.h" |
| |
| U_NAMESPACE_USE |
| |
| /* compare canonically equivalent ------------------------------------------- */ |
| |
| /* |
| * Compare two strings for canonical equivalence. |
| * Further options include case-insensitive comparison and |
| * code point order (as opposed to code unit order). |
| * |
| * In this function, canonical equivalence is optional as well. |
| * If canonical equivalence is tested, then both strings must fulfill |
| * the FCD check. |
| * |
| * Semantically, this is equivalent to |
| * strcmp[CodePointOrder](NFD(foldCase(s1)), NFD(foldCase(s2))) |
| * where code point order, NFD and foldCase are all optional. |
| * |
| * String comparisons almost always yield results before processing both strings |
| * completely. |
| * They are generally more efficient working incrementally instead of |
| * performing the sub-processing (strlen, normalization, case-folding) |
| * on the entire strings first. |
| * |
| * It is also unnecessary to not normalize identical characters. |
| * |
| * This function works in principle as follows: |
| * |
| * loop { |
| * get one code unit c1 from s1 (-1 if end of source) |
| * get one code unit c2 from s2 (-1 if end of source) |
| * |
| * if(either string finished) { |
| * return result; |
| * } |
| * if(c1==c2) { |
| * continue; |
| * } |
| * |
| * // c1!=c2 |
| * try to decompose/case-fold c1/c2, and continue if one does; |
| * |
| * // still c1!=c2 and neither decomposes/case-folds, return result |
| * return c1-c2; |
| * } |
| * |
| * When a character decomposes, then the pointer for that source changes to |
| * the decomposition, pushing the previous pointer onto a stack. |
| * When the end of the decomposition is reached, then the code unit reader |
| * pops the previous source from the stack. |
| * (Same for case-folding.) |
| * |
| * This is complicated further by operating on variable-width UTF-16. |
| * The top part of the loop works on code units, while lookups for decomposition |
| * and case-folding need code points. |
| * Code points are assembled after the equality/end-of-source part. |
| * The source pointer is only advanced beyond all code units when the code point |
| * actually decomposes/case-folds. |
| * |
| * If we were on a trail surrogate unit when assembling a code point, |
| * and the code point decomposes/case-folds, then the decomposition/folding |
| * result must be compared with the part of the other string that corresponds to |
| * this string's lead surrogate. |
| * Since we only assemble a code point when hitting a trail unit when the |
| * preceding lead units were identical, we back up the other string by one unit |
| * in such a case. |
| * |
| * The optional code point order comparison at the end works with |
| * the same fix-up as the other code point order comparison functions. |
| * See ustring.c and the comment near the end of this function. |
| * |
| * Assumption: A decomposition or case-folding result string never contains |
| * a single surrogate. This is a safe assumption in the Unicode Standard. |
| * Therefore, we do not need to check for surrogate pairs across |
| * decomposition/case-folding boundaries. |
| * |
| * Further assumptions (see verifications tstnorm.cpp): |
| * The API function checks for FCD first, while the core function |
| * first case-folds and then decomposes. This requires that case-folding does not |
| * un-FCD any strings. |
| * |
| * The API function may also NFD the input and turn off decomposition. |
| * This requires that case-folding does not un-NFD strings either. |
| * |
| * TODO If any of the above two assumptions is violated, |
| * then this entire code must be re-thought. |
| * If this happens, then a simple solution is to case-fold both strings up front |
| * and to turn off UNORM_INPUT_IS_FCD. |
| * We already do this when not both strings are in FCD because makeFCD |
| * would be a partial NFD before the case folding, which does not work. |
| * Note that all of this is only a problem when case-folding _and_ |
| * canonical equivalence come together. |
| * (Comments in unorm_compare() are more up to date than this TODO.) |
| */ |
| |
| /* stack element for previous-level source/decomposition pointers */ |
| struct CmpEquivLevel { |
| const UChar *start, *s, *limit; |
| }; |
| typedef struct CmpEquivLevel CmpEquivLevel; |
| |
| /** |
| * Internal option for unorm_cmpEquivFold() for decomposing. |
| * If not set, just do strcasecmp(). |
| */ |
| #define _COMPARE_EQUIV 0x80000 |
| |
| /* internal function */ |
| static int32_t |
| unorm_cmpEquivFold(const UChar *s1, int32_t length1, |
| const UChar *s2, int32_t length2, |
| uint32_t options, |
| UErrorCode *pErrorCode) { |
| const Normalizer2Impl *nfcImpl; |
| |
| /* current-level start/limit - s1/s2 as current */ |
| const UChar *start1, *start2, *limit1, *limit2; |
| |
| /* decomposition and case folding variables */ |
| const UChar *p; |
| int32_t length; |
| |
| /* stacks of previous-level start/current/limit */ |
| CmpEquivLevel stack1[2], stack2[2]; |
| |
| /* buffers for algorithmic decompositions */ |
| UChar decomp1[4], decomp2[4]; |
| |
| /* 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 one of the options _COMPARE_EQUIV and U_COMPARE_IGNORE_CASE is set |
| * otherwise this function must behave exactly as uprv_strCompare() |
| * not checking for that here makes testing this function easier |
| */ |
| |
| /* normalization/properties data loaded? */ |
| if((options&_COMPARE_EQUIV)!=0) { |
| nfcImpl=Normalizer2Factory::getNFCImpl(*pErrorCode); |
| } else { |
| nfcImpl=NULL; |
| } |
| 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 && (options&U_COMPARE_IGNORE_CASE) && |
| (length=ucase_toFullFolding((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 && (options&U_COMPARE_IGNORE_CASE) && |
| (length=ucase_toFullFolding((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; |
| } |
| |
| if( level1<2 && (options&_COMPARE_EQUIV) && |
| 0!=(p=nfcImpl->getDecomposition((UChar32)cp1, decomp1, length)) |
| ) { |
| /* cp1 decomposes into p[length] */ |
| if(U_IS_SURROGATE(c1)) { |
| if(U_IS_SURROGATE_LEAD(c1)) { |
| /* advance beyond source surrogate pair if it decomposes */ |
| ++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[level1].start=start1; |
| stack1[level1].s=s1; |
| stack1[level1].limit=limit1; |
| ++level1; |
| |
| /* set empty intermediate level if skipped */ |
| if(level1<2) { |
| stack1[level1++].start=NULL; |
| } |
| |
| /* set next level pointers to decomposition */ |
| start1=s1=p; |
| limit1=p+length; |
| |
| /* get ready to read from decomposition, continue with loop */ |
| c1=-1; |
| continue; |
| } |
| |
| if( level2<2 && (options&_COMPARE_EQUIV) && |
| 0!=(p=nfcImpl->getDecomposition((UChar32)cp2, decomp2, length)) |
| ) { |
| /* cp2 decomposes into p[length] */ |
| if(U_IS_SURROGATE(c2)) { |
| if(U_IS_SURROGATE_LEAD(c2)) { |
| /* advance beyond source surrogate pair if it decomposes */ |
| ++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[level2].start=start2; |
| stack2[level2].s=s2; |
| stack2[level2].limit=limit2; |
| ++level2; |
| |
| /* set empty intermediate level if skipped */ |
| if(level2<2) { |
| stack2[level2++].start=NULL; |
| } |
| |
| /* set next level pointers to decomposition */ |
| start2=s2=p; |
| limit2=p+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; |
| } |
| } |
| |
| static |
| UBool _normalize(const Normalizer2 *n2, const UChar *s, int32_t length, |
| UnicodeString &normalized, UErrorCode *pErrorCode) { |
| UnicodeString str(length<0, s, length); |
| |
| // check if s fulfill the conditions |
| int32_t spanQCYes=n2->spanQuickCheckYes(str, *pErrorCode); |
| if (U_FAILURE(*pErrorCode)) { |
| return FALSE; |
| } |
| /* |
| * ICU 2.4 had a further optimization: |
| * If both strings were not in FCD, then they were both NFD'ed, |
| * and the _COMPARE_EQUIV option was turned off. |
| * It is not entirely clear that this is valid with the current |
| * definition of the canonical caseless match. |
| * Therefore, ICU 2.6 removes that optimization. |
| */ |
| if(spanQCYes<str.length()) { |
| UnicodeString unnormalized=str.tempSubString(spanQCYes); |
| normalized.setTo(FALSE, str.getBuffer(), spanQCYes); |
| n2->normalizeSecondAndAppend(normalized, unnormalized, *pErrorCode); |
| if (U_SUCCESS(*pErrorCode)) { |
| return TRUE; |
| } |
| } |
| return FALSE; |
| } |
| |
| U_CAPI int32_t U_EXPORT2 |
| unorm_compare(const UChar *s1, int32_t length1, |
| const UChar *s2, int32_t length2, |
| uint32_t options, |
| UErrorCode *pErrorCode) { |
| /* argument checking */ |
| if(U_FAILURE(*pErrorCode)) { |
| return 0; |
| } |
| if(s1==0 || length1<-1 || s2==0 || length2<-1) { |
| *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR; |
| return 0; |
| } |
| |
| UnicodeString fcd1, fcd2; |
| int32_t normOptions=(int32_t)(options>>UNORM_COMPARE_NORM_OPTIONS_SHIFT); |
| options|=_COMPARE_EQUIV; |
| |
| /* |
| * UAX #21 Case Mappings, as fixed for Unicode version 4 |
| * (see Jitterbug 2021), defines a canonical caseless match as |
| * |
| * A string X is a canonical caseless match |
| * for a string Y if and only if |
| * NFD(toCasefold(NFD(X))) = NFD(toCasefold(NFD(Y))) |
| * |
| * For better performance, we check for FCD (or let the caller tell us that |
| * both strings are in FCD) for the inner normalization. |
| * BasicNormalizerTest::FindFoldFCDExceptions() makes sure that |
| * case-folding preserves the FCD-ness of a string. |
| * The outer normalization is then only performed by unorm_cmpEquivFold() |
| * when there is a difference. |
| * |
| * Exception: When using the Turkic case-folding option, we do perform |
| * full NFD first. This is because in the Turkic case precomposed characters |
| * with 0049 capital I or 0069 small i fold differently whether they |
| * are first decomposed or not, so an FCD check - a check only for |
| * canonical order - is not sufficient. |
| */ |
| if(!(options&UNORM_INPUT_IS_FCD) || (options&U_FOLD_CASE_EXCLUDE_SPECIAL_I)) { |
| const Normalizer2 *n2; |
| if(options&U_FOLD_CASE_EXCLUDE_SPECIAL_I) { |
| n2=Normalizer2::getNFDInstance(*pErrorCode); |
| } else { |
| n2=Normalizer2Factory::getFCDInstance(*pErrorCode); |
| } |
| if (U_FAILURE(*pErrorCode)) { |
| return 0; |
| } |
| |
| if(normOptions&UNORM_UNICODE_3_2) { |
| const UnicodeSet *uni32=uniset_getUnicode32Instance(*pErrorCode); |
| FilteredNormalizer2 fn2(*n2, *uni32); |
| if(_normalize(&fn2, s1, length1, fcd1, pErrorCode)) { |
| s1=fcd1.getBuffer(); |
| length1=fcd1.length(); |
| } |
| if(_normalize(&fn2, s2, length2, fcd2, pErrorCode)) { |
| s2=fcd2.getBuffer(); |
| length2=fcd2.length(); |
| } |
| } else { |
| if(_normalize(n2, s1, length1, fcd1, pErrorCode)) { |
| s1=fcd1.getBuffer(); |
| length1=fcd1.length(); |
| } |
| if(_normalize(n2, s2, length2, fcd2, pErrorCode)) { |
| s2=fcd2.getBuffer(); |
| length2=fcd2.length(); |
| } |
| } |
| } |
| |
| if(U_SUCCESS(*pErrorCode)) { |
| return unorm_cmpEquivFold(s1, length1, s2, length2, options, pErrorCode); |
| } else { |
| return 0; |
| } |
| } |
| |
| #endif /* #if !UCONFIG_NO_NORMALIZATION */ |
