Check in the pristine copy of ICU 4.6...

icu46/source/common/caniter.cpp

+/*
+ *****************************************************************************
+ * Copyright (C) 1996-2010, International Business Machines Corporation and  *
+ * others. All Rights Reserved.                                              *
+ *****************************************************************************
+ */
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_NORMALIZATION
+
+#include "unicode/caniter.h"
+#include "unicode/normalizer2.h"
+#include "unicode/uchar.h"
+#include "unicode/uniset.h"
+#include "unicode/usetiter.h"
+#include "unicode/ustring.h"
+#include "cmemory.h"
+#include "hash.h"
+#include "normalizer2impl.h"
+
+/**
+ * This class allows one to iterate through all the strings that are canonically equivalent to a given
+ * string. For example, here are some sample results:
+Results for: {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
+1: \u0041\u030A\u0064\u0307\u0327
+ = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
+2: \u0041\u030A\u0064\u0327\u0307
+ = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
+3: \u0041\u030A\u1E0B\u0327
+ = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
+4: \u0041\u030A\u1E11\u0307
+ = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
+5: \u00C5\u0064\u0307\u0327
+ = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
+6: \u00C5\u0064\u0327\u0307
+ = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
+7: \u00C5\u1E0B\u0327
+ = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
+8: \u00C5\u1E11\u0307
+ = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
+9: \u212B\u0064\u0307\u0327
+ = {ANGSTROM SIGN}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
+10: \u212B\u0064\u0327\u0307
+ = {ANGSTROM SIGN}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
+11: \u212B\u1E0B\u0327
+ = {ANGSTROM SIGN}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
+12: \u212B\u1E11\u0307
+ = {ANGSTROM SIGN}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
+ *<br>Note: the code is intended for use with small strings, and is not suitable for larger ones,
+ * since it has not been optimized for that situation.
+ *@author M. Davis
+ *@draft
+ */
+
+// public
+
+U_NAMESPACE_BEGIN
+
+// TODO: add boilerplate methods.
+
+UOBJECT_DEFINE_RTTI_IMPLEMENTATION(CanonicalIterator)
+
+/**
+ *@param source string to get results for
+ */
+CanonicalIterator::CanonicalIterator(const UnicodeString &sourceStr, UErrorCode &status) :
+    pieces(NULL),
+    pieces_length(0),
+    pieces_lengths(NULL),
+    current(NULL),
+    current_length(0),
+    nfd(*Normalizer2Factory::getNFDInstance(status)),
+    nfcImpl(*Normalizer2Factory::getNFCImpl(status))
+{
+    if(U_SUCCESS(status) && nfcImpl.ensureCanonIterData(status)) {
+      setSource(sourceStr, status);
+    }
+}
+
+CanonicalIterator::~CanonicalIterator() {
+  cleanPieces();
+}
+
+void CanonicalIterator::cleanPieces() {
+    int32_t i = 0;
+    if(pieces != NULL) {
+        for(i = 0; i < pieces_length; i++) {
+            if(pieces[i] != NULL) {
+                delete[] pieces[i];
+            }
+        }
+        uprv_free(pieces);
+        pieces = NULL;
+        pieces_length = 0;
+    }
+    if(pieces_lengths != NULL) {
+        uprv_free(pieces_lengths);
+        pieces_lengths = NULL;
+    }
+    if(current != NULL) {
+        uprv_free(current);
+        current = NULL;
+        current_length = 0;
+    }
+}
+
+/**
+ *@return gets the source: NOTE: it is the NFD form of source
+ */
+UnicodeString CanonicalIterator::getSource() {
+  return source;
+}
+
+/**
+ * Resets the iterator so that one can start again from the beginning.
+ */
+void CanonicalIterator::reset() {
+    done = FALSE;
+    for (int i = 0; i < current_length; ++i) {
+        current[i] = 0;
+    }
+}
+
+/**
+ *@return the next string that is canonically equivalent. The value null is returned when
+ * the iteration is done.
+ */
+UnicodeString CanonicalIterator::next() {
+    int32_t i = 0;
+
+    if (done) {
+      buffer.setToBogus();
+      return buffer;
+    }
+
+    // delete old contents
+    buffer.remove();
+
+    // construct return value
+
+    for (i = 0; i < pieces_length; ++i) {
+        buffer.append(pieces[i][current[i]]);
+    }
+    //String result = buffer.toString(); // not needed
+
+    // find next value for next time
+
+    for (i = current_length - 1; ; --i) {
+        if (i < 0) {
+            done = TRUE;
+            break;
+        }
+        current[i]++;
+        if (current[i] < pieces_lengths[i]) break; // got sequence
+        current[i] = 0;
+    }
+    return buffer;
+}
+
+/**
+ *@param set the source string to iterate against. This allows the same iterator to be used
+ * while changing the source string, saving object creation.
+ */
+void CanonicalIterator::setSource(const UnicodeString &newSource, UErrorCode &status) {
+    int32_t list_length = 0;
+    UChar32 cp = 0;
+    int32_t start = 0;
+    int32_t i = 0;
+    UnicodeString *list = NULL;
+
+    nfd.normalize(newSource, source, status);
+    if(U_FAILURE(status)) {
+      return;
+    }
+    done = FALSE;
+
+    cleanPieces();
+
+    // catch degenerate case
+    if (newSource.length() == 0) {
+        pieces = (UnicodeString **)uprv_malloc(sizeof(UnicodeString *));
+        pieces_lengths = (int32_t*)uprv_malloc(1 * sizeof(int32_t));
+        pieces_length = 1;
+        current = (int32_t*)uprv_malloc(1 * sizeof(int32_t));
+        current_length = 1;
+        if (pieces == NULL || pieces_lengths == NULL || current == NULL) {
+            status = U_MEMORY_ALLOCATION_ERROR;
+            goto CleanPartialInitialization;
+        }
+        current[0] = 0;
+        pieces[0] = new UnicodeString[1];
+        pieces_lengths[0] = 1;
+        if (pieces[0] == 0) {
+            status = U_MEMORY_ALLOCATION_ERROR;
+            goto CleanPartialInitialization;
+        }
+        return;
+    }
+
+
+    list = new UnicodeString[source.length()];
+    if (list == 0) {
+        status = U_MEMORY_ALLOCATION_ERROR;
+        goto CleanPartialInitialization;
+    }
+
+    // i should initialy be the number of code units at the 
+    // start of the string
+    i = UTF16_CHAR_LENGTH(source.char32At(0));
+    //int32_t i = 1;
+    // find the segments
+    // This code iterates through the source string and 
+    // extracts segments that end up on a codepoint that
+    // doesn't start any decompositions. (Analysis is done
+    // on the NFD form - see above).
+    for (; i < source.length(); i += UTF16_CHAR_LENGTH(cp)) {
+        cp = source.char32At(i);
+        if (nfcImpl.isCanonSegmentStarter(cp)) {
+            source.extract(start, i-start, list[list_length++]); // add up to i
+            start = i;
+        }
+    }
+    source.extract(start, i-start, list[list_length++]); // add last one
+
+
+    // allocate the arrays, and find the strings that are CE to each segment
+    pieces = (UnicodeString **)uprv_malloc(list_length * sizeof(UnicodeString *));
+    pieces_length = list_length;
+    pieces_lengths = (int32_t*)uprv_malloc(list_length * sizeof(int32_t));
+    current = (int32_t*)uprv_malloc(list_length * sizeof(int32_t));
+    current_length = list_length;
+    if (pieces == NULL || pieces_lengths == NULL || current == NULL) {
+        status = U_MEMORY_ALLOCATION_ERROR;
+        goto CleanPartialInitialization;
+    }
+
+    for (i = 0; i < current_length; i++) {
+        current[i] = 0;
+    }
+    // for each segment, get all the combinations that can produce 
+    // it after NFD normalization
+    for (i = 0; i < pieces_length; ++i) {
+        //if (PROGRESS) printf("SEGMENT\n");
+        pieces[i] = getEquivalents(list[i], pieces_lengths[i], status);
+    }
+
+    delete[] list;
+    return;
+// Common section to cleanup all local variables and reset object variables.
+CleanPartialInitialization:
+    if (list != NULL) {
+        delete[] list;
+    }
+    cleanPieces();
+}
+
+/**
+ * Dumb recursive implementation of permutation.
+ * TODO: optimize
+ * @param source the string to find permutations for
+ * @return the results in a set.
+ */
+void U_EXPORT2 CanonicalIterator::permute(UnicodeString &source, UBool skipZeros, Hashtable *result, UErrorCode &status) {
+    if(U_FAILURE(status)) {
+        return;
+    }
+    //if (PROGRESS) printf("Permute: %s\n", UToS(Tr(source)));
+    int32_t i = 0;
+
+    // optimization:
+    // if zero or one character, just return a set with it
+    // we check for length < 2 to keep from counting code points all the time
+    if (source.length() <= 2 && source.countChar32() <= 1) {
+        UnicodeString *toPut = new UnicodeString(source);
+        /* test for NULL */
+        if (toPut == 0) {
+            status = U_MEMORY_ALLOCATION_ERROR;
+            return;
+        }
+        result->put(source, toPut, status);
+        return;
+    }
+
+    // otherwise iterate through the string, and recursively permute all the other characters
+    UChar32 cp;
+    Hashtable subpermute(status);
+    if(U_FAILURE(status)) {
+        return;
+    }
+    subpermute.setValueDeleter(uhash_deleteUnicodeString);
+
+    for (i = 0; i < source.length(); i += UTF16_CHAR_LENGTH(cp)) {
+        cp = source.char32At(i);
+        const UHashElement *ne = NULL;
+        int32_t el = -1;
+        UnicodeString subPermuteString = source;
+
+        // optimization:
+        // if the character is canonical combining class zero,
+        // don't permute it
+        if (skipZeros && i != 0 && u_getCombiningClass(cp) == 0) {
+            //System.out.println("Skipping " + Utility.hex(UTF16.valueOf(source, i)));
+            continue;
+        }
+
+        subpermute.removeAll();
+
+        // see what the permutations of the characters before and after this one are
+        //Hashtable *subpermute = permute(source.substring(0,i) + source.substring(i + UTF16.getCharCount(cp)));
+        permute(subPermuteString.replace(i, UTF16_CHAR_LENGTH(cp), NULL, 0), skipZeros, &subpermute, status);
+        /* Test for buffer overflows */
+        if(U_FAILURE(status)) {
+            return;
+        }
+        // The upper replace is destructive. The question is do we have to make a copy, or we don't care about the contents 
+        // of source at this point.
+
+        // prefix this character to all of them
+        ne = subpermute.nextElement(el);
+        while (ne != NULL) {
+            UnicodeString *permRes = (UnicodeString *)(ne->value.pointer);
+            UnicodeString *chStr = new UnicodeString(cp);
+            //test for  NULL
+            if (chStr == NULL) {
+                status = U_MEMORY_ALLOCATION_ERROR;
+                return;
+            }
+            chStr->append(*permRes); //*((UnicodeString *)(ne->value.pointer));
+            //if (PROGRESS) printf("  Piece: %s\n", UToS(*chStr));
+            result->put(*chStr, chStr, status);
+            ne = subpermute.nextElement(el);
+        }
+    }
+    //return result;
+}
+
+// privates
+
+// we have a segment, in NFD. Find all the strings that are canonically equivalent to it.
+UnicodeString* CanonicalIterator::getEquivalents(const UnicodeString &segment, int32_t &result_len, UErrorCode &status) {
+    Hashtable result(status);
+    Hashtable permutations(status);
+    Hashtable basic(status);
+    if (U_FAILURE(status)) {
+        return 0;
+    }
+    result.setValueDeleter(uhash_deleteUnicodeString);
+    permutations.setValueDeleter(uhash_deleteUnicodeString);
+    basic.setValueDeleter(uhash_deleteUnicodeString);
+
+    UChar USeg[256];
+    int32_t segLen = segment.extract(USeg, 256, status);
+    getEquivalents2(&basic, USeg, segLen, status);
+
+    // now get all the permutations
+    // add only the ones that are canonically equivalent
+    // TODO: optimize by not permuting any class zero.
+
+    const UHashElement *ne = NULL;
+    int32_t el = -1;
+    //Iterator it = basic.iterator();
+    ne = basic.nextElement(el);
+    //while (it.hasNext())
+    while (ne != NULL) {
+        //String item = (String) it.next();
+        UnicodeString item = *((UnicodeString *)(ne->value.pointer));
+
+        permutations.removeAll();
+        permute(item, CANITER_SKIP_ZEROES, &permutations, status);
+        const UHashElement *ne2 = NULL;
+        int32_t el2 = -1;
+        //Iterator it2 = permutations.iterator();
+        ne2 = permutations.nextElement(el2);
+        //while (it2.hasNext())
+        while (ne2 != NULL) {
+            //String possible = (String) it2.next();
+            //UnicodeString *possible = new UnicodeString(*((UnicodeString *)(ne2->value.pointer)));
+            UnicodeString possible(*((UnicodeString *)(ne2->value.pointer)));
+            UnicodeString attempt;
+            nfd.normalize(possible, attempt, status);
+
+            // TODO: check if operator == is semanticaly the same as attempt.equals(segment)
+            if (attempt==segment) {
+                //if (PROGRESS) printf("Adding Permutation: %s\n", UToS(Tr(*possible)));
+                // TODO: use the hashtable just to catch duplicates - store strings directly (somehow).
+                result.put(possible, new UnicodeString(possible), status); //add(possible);
+            } else {
+                //if (PROGRESS) printf("-Skipping Permutation: %s\n", UToS(Tr(*possible)));
+            }
+
+            ne2 = permutations.nextElement(el2);
+        }
+        ne = basic.nextElement(el);
+    }
+
+    /* Test for buffer overflows */
+    if(U_FAILURE(status)) {
+        return 0;
+    }
+    // convert into a String[] to clean up storage
+    //String[] finalResult = new String[result.size()];
+    UnicodeString *finalResult = NULL;
+    int32_t resultCount;
+    if((resultCount = result.count())) {
+        finalResult = new UnicodeString[resultCount];
+        if (finalResult == 0) {
+            status = U_MEMORY_ALLOCATION_ERROR;
+            return NULL;
+        }
+    }
+    else {
+        status = U_ILLEGAL_ARGUMENT_ERROR;
+        return NULL;
+    }
+    //result.toArray(finalResult);
+    result_len = 0;
+    el = -1;
+    ne = result.nextElement(el);
+    while(ne != NULL) {
+        finalResult[result_len++] = *((UnicodeString *)(ne->value.pointer));
+        ne = result.nextElement(el);
+    }
+
+
+    return finalResult;
+}
+
+Hashtable *CanonicalIterator::getEquivalents2(Hashtable *fillinResult, const UChar *segment, int32_t segLen, UErrorCode &status) {
+
+    if (U_FAILURE(status)) {
+        return NULL;
+    }
+
+    //if (PROGRESS) printf("Adding: %s\n", UToS(Tr(segment)));
+
+    UnicodeString toPut(segment, segLen);
+
+    fillinResult->put(toPut, new UnicodeString(toPut), status);
+
+    UnicodeSet starts;
+
+    // cycle through all the characters
+    UChar32 cp;
+    for (int32_t i = 0; i < segLen; i += UTF16_CHAR_LENGTH(cp)) {
+        // see if any character is at the start of some decomposition
+        UTF_GET_CHAR(segment, 0, i, segLen, cp);
+        if (!nfcImpl.getCanonStartSet(cp, starts)) {
+            continue;
+        }
+        // if so, see which decompositions match
+        UnicodeSetIterator iter(starts);
+        while (iter.next()) {
+            UChar32 cp2 = iter.getCodepoint();
+            Hashtable remainder(status);
+            remainder.setValueDeleter(uhash_deleteUnicodeString);
+            if (extract(&remainder, cp2, segment, segLen, i, status) == NULL) {
+                continue;
+            }
+
+            // there were some matches, so add all the possibilities to the set.
+            UnicodeString prefix(segment, i);
+            prefix += cp2;
+
+            int32_t el = -1;
+            const UHashElement *ne = remainder.nextElement(el);
+            while (ne != NULL) {
+                UnicodeString item = *((UnicodeString *)(ne->value.pointer));
+                UnicodeString *toAdd = new UnicodeString(prefix);
+                /* test for NULL */
+                if (toAdd == 0) {
+                    status = U_MEMORY_ALLOCATION_ERROR;
+                    return NULL;
+                }
+                *toAdd += item;
+                fillinResult->put(*toAdd, toAdd, status);
+
+                //if (PROGRESS) printf("Adding: %s\n", UToS(Tr(*toAdd)));
+
+                ne = remainder.nextElement(el);
+            }
+        }
+    }
+
+    /* Test for buffer overflows */
+    if(U_FAILURE(status)) {
+        return NULL;
+    }
+    return fillinResult;
+}
+
+/**
+ * See if the decomposition of cp2 is at segment starting at segmentPos 
+ * (with canonical rearrangment!)
+ * If so, take the remainder, and return the equivalents 
+ */
+Hashtable *CanonicalIterator::extract(Hashtable *fillinResult, UChar32 comp, const UChar *segment, int32_t segLen, int32_t segmentPos, UErrorCode &status) {
+//Hashtable *CanonicalIterator::extract(UChar32 comp, const UnicodeString &segment, int32_t segLen, int32_t segmentPos, UErrorCode &status) {
+    //if (PROGRESS) printf(" extract: %s, ", UToS(Tr(UnicodeString(comp))));
+    //if (PROGRESS) printf("%s, %i\n", UToS(Tr(segment)), segmentPos);
+
+    if (U_FAILURE(status)) {
+        return NULL;
+    }
+
+    UnicodeString temp(comp);
+    int32_t inputLen=temp.length();
+    UnicodeString decompString;
+    nfd.normalize(temp, decompString, status);
+    const UChar *decomp=decompString.getBuffer();
+    int32_t decompLen=decompString.length();
+
+    // See if it matches the start of segment (at segmentPos)
+    UBool ok = FALSE;
+    UChar32 cp;
+    int32_t decompPos = 0;
+    UChar32 decompCp;
+    U16_NEXT(decomp, decompPos, decompLen, decompCp);
+
+    int32_t i = segmentPos;
+    while(i < segLen) {
+        U16_NEXT(segment, i, segLen, cp);
+
+        if (cp == decompCp) { // if equal, eat another cp from decomp
+
+            //if (PROGRESS) printf("  matches: %s\n", UToS(Tr(UnicodeString(cp))));
+
+            if (decompPos == decompLen) { // done, have all decomp characters!
+                temp.append(segment+i, segLen-i);
+                ok = TRUE;
+                break;
+            }
+            U16_NEXT(decomp, decompPos, decompLen, decompCp);
+        } else {
+            //if (PROGRESS) printf("  buffer: %s\n", UToS(Tr(UnicodeString(cp))));
+
+            // brute force approach
+            temp.append(cp);
+
+            /* TODO: optimize
+            // since we know that the classes are monotonically increasing, after zero
+            // e.g. 0 5 7 9 0 3
+            // we can do an optimization
+            // there are only a few cases that work: zero, less, same, greater
+            // if both classes are the same, we fail
+            // if the decomp class < the segment class, we fail
+
+            segClass = getClass(cp);
+            if (decompClass <= segClass) return null;
+            */
+        }
+    }
+    if (!ok)
+        return NULL; // we failed, characters left over
+
+    //if (PROGRESS) printf("Matches\n");
+
+    if (inputLen == temp.length()) {
+        fillinResult->put(UnicodeString(), new UnicodeString(), status);
+        return fillinResult; // succeed, but no remainder
+    }
+
+    // brute force approach
+    // check to make sure result is canonically equivalent
+    UnicodeString trial;
+    nfd.normalize(temp, trial, status);
+    if(U_FAILURE(status) || trial.compare(segment+segmentPos, segLen - segmentPos) != 0) {
+        return NULL;
+    }
+
+    return getEquivalents2(fillinResult, temp.getBuffer()+inputLen, temp.length()-inputLen, status);
+}
+
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_NORMALIZATION */