The Tor Browser: comparison intl/icu/source/common/unormcmp.cpp

--1:000000000000
+:85c8b92bec9c
+/*
+*******************************************************************************
+*
+*   Copyright (C) 2001-2011, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*
+*******************************************************************************
+*   file name:  unormcmp.cpp
+*   encoding:   US-ASCII
+*   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
+#define LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0]))
+/* 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;
+const UCaseProps *csp;
+/* 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((options&U_COMPARE_IGNORE_CASE)!=0) {
+csp=ucase_getSingleton();
+} else {
+csp=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(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 && (options&U_COMPARE_IGNORE_CASE) &&
+(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;
+}
+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=Normalizer2Factory::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 */

The Tor Browser / file comparison

comparison: intl/icu/source/common/unormcmp.cpp

intl/icu/source/common/unormcmp.cpp