| /** |
| ******************************************************************************* |
| * Copyright (C) 2006-2008, 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( const UnicodeSet &set ) { |
| fSet = set; |
| // Compact for caching |
| fSet.compact(); |
| } |
| |
| /*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); |
| fMarkSet.add(0x0020); |
| 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); |
| |
| // Compact for caching. |
| fMarkSet.compact(); |
| fEndWordSet.compact(); |
| fBeginWordSet.compact(); |
| fSuffixSet.compact(); |
| } |
| |
| 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; |
| for (;;) { |
| 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 */ |
