149 lines
5.1 KiB
C++
149 lines
5.1 KiB
C++
/*
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**********************************************************************
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* Copyright (C) 1999, International Business Machines
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* Corporation and others. All Rights Reserved.
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**********************************************************************
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* Date Name Description
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* 11/17/99 aliu Creation.
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**********************************************************************
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*/
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#include "unicode/rbt.h"
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#include "rbt_pars.h"
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#include "rbt_data.h"
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#include "rbt_rule.h"
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#include "unicode/rep.h"
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void RuleBasedTransliterator::_construct(const UnicodeString& rules,
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Direction direction,
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UErrorCode& status,
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ParseError* parseError) {
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data = 0;
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isDataOwned = TRUE;
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if (U_SUCCESS(status)) {
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data = TransliterationRuleParser::parse(rules, direction, parseError);
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if (data == 0) {
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status = U_ILLEGAL_ARGUMENT_ERROR;
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} else {
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setMaximumContextLength(data->ruleSet.getMaximumContextLength());
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}
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}
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}
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RuleBasedTransliterator::RuleBasedTransliterator(const UnicodeString& ID,
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const TransliterationRuleData* theData,
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UnicodeFilter* adoptedFilter) :
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Transliterator(ID, adoptedFilter),
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data((TransliterationRuleData*)theData), // cast away const
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isDataOwned(FALSE) {
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setMaximumContextLength(data->ruleSet.getMaximumContextLength());
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}
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/**
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* Copy constructor. Since the data object is immutable, we can share
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* it with other objects -- no need to clone it.
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*/
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RuleBasedTransliterator::RuleBasedTransliterator(
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const RuleBasedTransliterator& other) :
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Transliterator(other), data(other.data) {
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// TODO: Finish this -- implement with correct data ownership handling
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if (other.isDataOwned) {
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// TODO: At this point we need to make our own copy of the data.
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} else {
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isDataOwned = FALSE;
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}
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}
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/**
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* Destructor. We do NOT own the data object, so we do not delete it.
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*/
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RuleBasedTransliterator::~RuleBasedTransliterator() {
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if (isDataOwned) {
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delete data;
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}
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}
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Transliterator* // Covariant return NOT ALLOWED (for portability)
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RuleBasedTransliterator::clone(void) const {
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return new RuleBasedTransliterator(*this);
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}
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/**
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* Implements {@link Transliterator#handleTransliterate}.
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*/
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void
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RuleBasedTransliterator::handleTransliterate(Replaceable& text, Position& index,
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bool_t isIncremental) const {
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/* We keep start and limit fixed the entire time,
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* relative to the text -- limit may move numerically if text is
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* inserted or removed. The cursor moves from start to limit, with
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* replacements happening under it.
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*
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* Example: rules 1. ab>x|y
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* 2. yc>z
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*
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* |eabcd start - no match, advance cursor
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* e|abcd match rule 1 - change text & adjust cursor
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* ex|ycd match rule 2 - change text & adjust cursor
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* exz|d no match, advance cursor
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* exzd| done
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*/
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int32_t start = index.start;
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int32_t limit = index.limit;
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int32_t cursor = index.cursor;
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/* A rule like
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* a>b|a
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* creates an infinite loop. To prevent that, we put an arbitrary
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* limit on the number of iterations that we take, one that is
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* high enough that any reasonable rules are ok, but low enough to
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* prevent a server from hanging. The limit is 16 times the
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* number of characters n, unless n is so large that 16n exceeds a
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* uint32_t.
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*/
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uint32_t loopCount = 0;
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uint32_t loopLimit = limit - cursor;
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if (loopLimit >= 0x10000000) {
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loopLimit = 0xFFFFFFFF;
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} else {
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loopLimit <<= 4;
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}
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bool_t isPartial = FALSE;
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while (cursor < limit && loopCount <= loopLimit) {
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TransliterationRule* r = isIncremental ?
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data->ruleSet.findIncrementalMatch(text, start, limit, cursor,
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*data, isPartial,
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getFilter()) :
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data->ruleSet.findMatch(text, start, limit,
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cursor, *data,
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getFilter());
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/* If we match a rule then apply it by replacing the key
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* with the rule output and repositioning the cursor
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* appropriately. If we get a partial match, then we
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* can't do anything without more text; return with the
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* cursor at the current position. If we get null, then
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* there is no match at this position, and we can advance
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* the cursor.
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*/
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if (r == 0) {
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if (isPartial) { // always FALSE unless isIncremental
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break;
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} else {
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++cursor;
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}
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} else {
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text.handleReplaceBetween(cursor, cursor + r->getKeyLength(),
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r->getOutput());
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limit += r->getOutput().length() - r->getKeyLength();
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cursor += r->getCursorPos();
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++loopCount;
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}
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}
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index.limit = limit;
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index.cursor = cursor;
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}
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