--- /dev/null
+/**
+ *******************************************************************************
+ * Copyright (C) 2006, International Business Machines Corporation and others. *
+ * All Rights Reserved. *
+ *******************************************************************************
+ */
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_BREAK_ITERATION
+
+#include "brkeng.h"
+#include "dictbe.h"
+#include "unicode/uniset.h"
+#include "unicode/chariter.h"
+#include "unicode/ubrk.h"
+#include "uvector.h"
+#include "triedict.h"
+
+U_NAMESPACE_BEGIN
+
+/*
+ ******************************************************************
+ */
+
+/*DictionaryBreakEngine::DictionaryBreakEngine() {
+ fTypes = 0;
+}*/
+
+DictionaryBreakEngine::DictionaryBreakEngine(uint32_t breakTypes) {
+ fTypes = breakTypes;
+}
+
+DictionaryBreakEngine::~DictionaryBreakEngine() {
+}
+
+UBool
+DictionaryBreakEngine::handles(UChar32 c, int32_t breakType) const {
+ return (breakType >= 0 && breakType < 32 && (((uint32_t)1 << breakType) & fTypes)
+ && fSet.contains(c));
+}
+
+int32_t
+DictionaryBreakEngine::findBreaks( UText *text,
+ int32_t startPos,
+ int32_t endPos,
+ UBool reverse,
+ int32_t breakType,
+ UStack &foundBreaks ) const {
+ int32_t result = 0;
+
+ // Find the span of characters included in the set.
+ int32_t start = (int32_t)utext_getNativeIndex(text);
+ int32_t current;
+ int32_t rangeStart;
+ int32_t rangeEnd;
+ UChar32 c = utext_current32(text);
+ if (reverse) {
+ UBool isDict = fSet.contains(c);
+ while((current = (int32_t)utext_getNativeIndex(text)) > startPos && isDict) {
+ c = utext_previous32(text);
+ isDict = fSet.contains(c);
+ }
+ rangeStart = (current < startPos) ? startPos : current+(isDict ? 0 : 1);
+ rangeEnd = start + 1;
+ }
+ else {
+ while((current = (int32_t)utext_getNativeIndex(text)) < endPos && fSet.contains(c)) {
+ utext_next32(text); // TODO: recast loop for postincrement
+ c = utext_current32(text);
+ }
+ rangeStart = start;
+ rangeEnd = current;
+ }
+ if (breakType >= 0 && breakType < 32 && (((uint32_t)1 << breakType) & fTypes)) {
+ result = divideUpDictionaryRange(text, rangeStart, rangeEnd, foundBreaks);
+ utext_setNativeIndex(text, current);
+ }
+
+ return result;
+}
+
+void
+DictionaryBreakEngine::setCharacters( UnicodeSet &set ) {
+ fSet = set;
+}
+
+/*void
+DictionaryBreakEngine::setBreakTypes( uint32_t breakTypes ) {
+ fTypes = breakTypes;
+}*/
+
+/*
+ ******************************************************************
+ */
+
+
+// Helper class for improving readability of the Thai word break
+// algorithm. The implementation is completely inline.
+
+// List size, limited by the maximum number of words in the dictionary
+// that form a nested sequence.
+#define POSSIBLE_WORD_LIST_MAX 20
+
+class PossibleWord {
+ private:
+ // list of word candidate lengths, in increasing length order
+ int32_t lengths[POSSIBLE_WORD_LIST_MAX];
+ int count; // Count of candidates
+ int32_t prefix; // The longest match with a dictionary word
+ int32_t offset; // Offset in the text of these candidates
+ int mark; // The preferred candidate's offset
+ int current; // The candidate we're currently looking at
+
+ public:
+ PossibleWord();
+ ~PossibleWord();
+
+ // Fill the list of candidates if needed, select the longest, and return the number found
+ int candidates( UText *text, const TrieWordDictionary *dict, int32_t rangeEnd );
+
+ // Select the currently marked candidate, point after it in the text, and invalidate self
+ int32_t acceptMarked( UText *text );
+
+ // Back up from the current candidate to the next shorter one; return TRUE if that exists
+ // and point the text after it
+ UBool backUp( UText *text );
+
+ // Return the longest prefix this candidate location shares with a dictionary word
+ int32_t longestPrefix();
+
+ // Mark the current candidate as the one we like
+ void markCurrent();
+};
+
+inline
+PossibleWord::PossibleWord() {
+ offset = -1;
+}
+
+inline
+PossibleWord::~PossibleWord() {
+}
+
+inline int
+PossibleWord::candidates( UText *text, const TrieWordDictionary *dict, int32_t rangeEnd ) {
+ // TODO: If getIndex is too slow, use offset < 0 and add discardAll()
+ int32_t start = (int32_t)utext_getNativeIndex(text);
+ if (start != offset) {
+ offset = start;
+ prefix = dict->matches(text, rangeEnd-start, lengths, count, sizeof(lengths)/sizeof(lengths[0]));
+ // Dictionary leaves text after longest prefix, not longest word. Back up.
+ if (count <= 0) {
+ utext_setNativeIndex(text, start);
+ }
+ }
+ if (count > 0) {
+ utext_setNativeIndex(text, start+lengths[count-1]);
+ }
+ current = count-1;
+ mark = current;
+ return count;
+}
+
+inline int32_t
+PossibleWord::acceptMarked( UText *text ) {
+ utext_setNativeIndex(text, offset + lengths[mark]);
+ return lengths[mark];
+}
+
+inline UBool
+PossibleWord::backUp( UText *text ) {
+ if (current > 0) {
+ utext_setNativeIndex(text, offset + lengths[--current]);
+ return TRUE;
+ }
+ return FALSE;
+}
+
+inline int32_t
+PossibleWord::longestPrefix() {
+ return prefix;
+}
+
+inline void
+PossibleWord::markCurrent() {
+ mark = current;
+}
+
+// How many words in a row are "good enough"?
+#define THAI_LOOKAHEAD 3
+
+// Will not combine a non-word with a preceding dictionary word longer than this
+#define THAI_ROOT_COMBINE_THRESHOLD 3
+
+// Will not combine a non-word that shares at least this much prefix with a
+// dictionary word, with a preceding word
+#define THAI_PREFIX_COMBINE_THRESHOLD 3
+
+// Ellision character
+#define THAI_PAIYANNOI 0x0E2F
+
+// Repeat character
+#define THAI_MAIYAMOK 0x0E46
+
+// Minimum word size
+#define THAI_MIN_WORD 2
+
+// Minimum number of characters for two words
+#define THAI_MIN_WORD_SPAN (THAI_MIN_WORD * 2)
+
+ThaiBreakEngine::ThaiBreakEngine(const TrieWordDictionary *adoptDictionary, UErrorCode &status)
+ : DictionaryBreakEngine((1<<UBRK_WORD) | (1<<UBRK_LINE)),
+ fDictionary(adoptDictionary)
+{
+ fThaiWordSet.applyPattern(UNICODE_STRING_SIMPLE("[[:Thai:]&[:LineBreak=SA:]]"), status);
+ if (U_SUCCESS(status)) {
+ setCharacters(fThaiWordSet);
+ }
+ fMarkSet.applyPattern(UNICODE_STRING_SIMPLE("[[:Thai:]&[:LineBreak=SA:]&[:M:]]"), status);
+ fEndWordSet = fThaiWordSet;
+ fEndWordSet.remove(0x0E31); // MAI HAN-AKAT
+ fEndWordSet.remove(0x0E40, 0x0E44); // SARA E through SARA AI MAIMALAI
+ fBeginWordSet.add(0x0E01, 0x0E2E); // KO KAI through HO NOKHUK
+ fBeginWordSet.add(0x0E40, 0x0E44); // SARA E through SARA AI MAIMALAI
+ fSuffixSet.add(THAI_PAIYANNOI);
+ fSuffixSet.add(THAI_MAIYAMOK);
+}
+
+ThaiBreakEngine::~ThaiBreakEngine() {
+ delete fDictionary;
+}
+
+int32_t
+ThaiBreakEngine::divideUpDictionaryRange( UText *text,
+ int32_t rangeStart,
+ int32_t rangeEnd,
+ UStack &foundBreaks ) const {
+ if ((rangeEnd - rangeStart) < THAI_MIN_WORD_SPAN) {
+ return 0; // Not enough characters for two words
+ }
+
+ uint32_t wordsFound = 0;
+ int32_t wordLength;
+ int32_t current;
+ UErrorCode status = U_ZERO_ERROR;
+ PossibleWord words[THAI_LOOKAHEAD];
+ UChar32 uc;
+
+ utext_setNativeIndex(text, rangeStart);
+
+ while (U_SUCCESS(status) && (current = (int32_t)utext_getNativeIndex(text)) < rangeEnd) {
+ wordLength = 0;
+
+ // Look for candidate words at the current position
+ int candidates = words[wordsFound%THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd);
+
+ // If we found exactly one, use that
+ if (candidates == 1) {
+ wordLength = words[wordsFound%THAI_LOOKAHEAD].acceptMarked(text);
+ wordsFound += 1;
+ }
+
+ // If there was more than one, see which one can take us forward the most words
+ else if (candidates > 1) {
+ // If we're already at the end of the range, we're done
+ if ((int32_t)utext_getNativeIndex(text) >= rangeEnd) {
+ goto foundBest;
+ }
+ do {
+ int wordsMatched = 1;
+ if (words[(wordsFound+1)%THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd) > 0) {
+ if (wordsMatched < 2) {
+ // Followed by another dictionary word; mark first word as a good candidate
+ words[wordsFound%THAI_LOOKAHEAD].markCurrent();
+ wordsMatched = 2;
+ }
+
+ // If we're already at the end of the range, we're done
+ if ((int32_t)utext_getNativeIndex(text) >= rangeEnd) {
+ goto foundBest;
+ }
+
+ // See if any of the possible second words is followed by a third word
+ do {
+ // If we find a third word, stop right away
+ if (words[(wordsFound+2)%THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd)) {
+ words[wordsFound%THAI_LOOKAHEAD].markCurrent();
+ goto foundBest;
+ }
+ }
+ while (words[(wordsFound+1)%THAI_LOOKAHEAD].backUp(text));
+ }
+ }
+ while (words[wordsFound%THAI_LOOKAHEAD].backUp(text));
+foundBest:
+ wordLength = words[wordsFound%THAI_LOOKAHEAD].acceptMarked(text);
+ wordsFound += 1;
+ }
+
+ // We come here after having either found a word or not. We look ahead to the
+ // next word. If it's not a dictionary word, we will combine it withe the word we
+ // just found (if there is one), but only if the preceding word does not exceed
+ // the threshold.
+ // The text iterator should now be positioned at the end of the word we found.
+ if ((int32_t)utext_getNativeIndex(text) < rangeEnd && wordLength < THAI_ROOT_COMBINE_THRESHOLD) {
+ // if it is a dictionary word, do nothing. If it isn't, then if there is
+ // no preceding word, or the non-word shares less than the minimum threshold
+ // of characters with a dictionary word, then scan to resynchronize
+ if (words[wordsFound%THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd) <= 0
+ && (wordLength == 0
+ || words[wordsFound%THAI_LOOKAHEAD].longestPrefix() < THAI_PREFIX_COMBINE_THRESHOLD)) {
+ // Look for a plausible word boundary
+ //TODO: This section will need a rework for UText.
+ int32_t remaining = rangeEnd - (current+wordLength);
+ UChar32 pc = utext_current32(text);
+ int32_t chars = 0;
+ while (TRUE) {
+ utext_next32(text);
+ uc = utext_current32(text);
+ // TODO: Here we're counting on the fact that the SA languages are all
+ // in the BMP. This should get fixed with the UText rework.
+ chars += 1;
+ if (--remaining <= 0) {
+ break;
+ }
+ if (fEndWordSet.contains(pc) && fBeginWordSet.contains(uc)) {
+ // Maybe. See if it's in the dictionary.
+ // NOTE: In the original Apple code, checked that the next
+ // two characters after uc were not 0x0E4C THANTHAKHAT before
+ // checking the dictionary. That is just a performance filter,
+ // but it's not clear it's faster than checking the trie.
+ int candidates = words[(wordsFound+1)%THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd);
+ utext_setNativeIndex(text, current+wordLength+chars);
+ if (candidates > 0) {
+ break;
+ }
+ }
+ pc = uc;
+ }
+
+ // Bump the word count if there wasn't already one
+ if (wordLength <= 0) {
+ wordsFound += 1;
+ }
+
+ // Update the length with the passed-over characters
+ wordLength += chars;
+ }
+ else {
+ // Back up to where we were for next iteration
+ utext_setNativeIndex(text, current+wordLength);
+ }
+ }
+
+ // Never stop before a combining mark.
+ int32_t currPos;
+ while ((currPos = (int32_t)utext_getNativeIndex(text)) < rangeEnd && fMarkSet.contains(utext_current32(text))) {
+ utext_next32(text);
+ wordLength += (int32_t)utext_getNativeIndex(text) - currPos;
+ }
+
+ // Look ahead for possible suffixes if a dictionary word does not follow.
+ // We do this in code rather than using a rule so that the heuristic
+ // resynch continues to function. For example, one of the suffix characters
+ // could be a typo in the middle of a word.
+ if ((int32_t)utext_getNativeIndex(text) < rangeEnd && wordLength > 0) {
+ if (words[wordsFound%THAI_LOOKAHEAD].candidates(text, fDictionary, rangeEnd) <= 0
+ && fSuffixSet.contains(uc = utext_current32(text))) {
+ if (uc == THAI_PAIYANNOI) {
+ if (!fSuffixSet.contains(utext_previous32(text))) {
+ // Skip over previous end and PAIYANNOI
+ utext_next32(text);
+ utext_next32(text);
+ wordLength += 1; // Add PAIYANNOI to word
+ uc = utext_current32(text); // Fetch next character
+ }
+ else {
+ // Restore prior position
+ utext_next32(text);
+ }
+ }
+ if (uc == THAI_MAIYAMOK) {
+ if (utext_previous32(text) != THAI_MAIYAMOK) {
+ // Skip over previous end and MAIYAMOK
+ utext_next32(text);
+ utext_next32(text);
+ wordLength += 1; // Add MAIYAMOK to word
+ }
+ else {
+ // Restore prior position
+ utext_next32(text);
+ }
+ }
+ }
+ else {
+ utext_setNativeIndex(text, current+wordLength);
+ }
+ }
+
+ // Did we find a word on this iteration? If so, push it on the break stack
+ if (wordLength > 0) {
+ foundBreaks.push((current+wordLength), status);
+ }
+ }
+
+ // Don't return a break for the end of the dictionary range if there is one there.
+ if (foundBreaks.peeki() >= rangeEnd) {
+ (void) foundBreaks.popi();
+ wordsFound -= 1;
+ }
+
+ return wordsFound;
+}
+
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_BREAK_ITERATION */
projects / apple / icu.git / blobdiff