/*
**********************************************************************
* Copyright (C) 1999-2012, International Business Machines
* Corporation and others. All Rights Reserved.
**********************************************************************
* Date Name Description
* 11/17/99 aliu Creation.
**********************************************************************
*/
#include "unicode/utypes.h"
#if !UCONFIG_NO_TRANSLITERATION
#include "unicode/rep.h"
#include "unicode/uniset.h"
#include "rbt_pars.h"
#include "rbt_data.h"
#include "rbt_rule.h"
#include "rbt.h"
#include "umutex.h"
U_NAMESPACE_BEGIN
UOBJECT_DEFINE_RTTI_IMPLEMENTATION(RuleBasedTransliterator)
static UMutex transliteratorDataMutex = U_MUTEX_INITIALIZER;
static Replaceable *gLockedText = NULL;
void RuleBasedTransliterator::_construct(const UnicodeString& rules,
UTransDirection direction,
UParseError& parseError,
UErrorCode& status) {
fData = 0;
isDataOwned = TRUE;
if (U_FAILURE(status)) {
return;
}
TransliteratorParser parser(status);
parser.parse(rules, direction, parseError, status);
if (U_FAILURE(status)) {
return;
}
if (parser.idBlockVector.size() != 0 ||
parser.compoundFilter != NULL ||
parser.dataVector.size() == 0) {
status = U_INVALID_RBT_SYNTAX; // ::ID blocks disallowed in RBT
return;
}
fData = (TransliterationRuleData*)parser.dataVector.orphanElementAt(0);
setMaximumContextLength(fData->ruleSet.getMaximumContextLength());
}
/**
* Constructs a new transliterator from the given rules.
* @param id the id for the transliterator.
* @param rules rules, separated by ';'
* @param direction either FORWARD or REVERSE.
* @param adoptedFilter the filter for this transliterator.
* @param parseError Struct to recieve information on position
* of error if an error is encountered
* @param status Output param set to success/failure code.
* @exception IllegalArgumentException if rules are malformed
* or direction is invalid.
*/
RuleBasedTransliterator::RuleBasedTransliterator(
const UnicodeString& id,
const UnicodeString& rules,
UTransDirection direction,
UnicodeFilter* adoptedFilter,
UParseError& parseError,
UErrorCode& status) :
Transliterator(id, adoptedFilter) {
_construct(rules, direction,parseError,status);
}
/**
* Constructs a new transliterator from the given rules.
* @param id the id for the transliterator.
* @param rules rules, separated by ';'
* @param direction either FORWARD or REVERSE.
* @param adoptedFilter the filter for this transliterator.
* @param status Output param set to success/failure code.
* @exception IllegalArgumentException if rules are malformed
* or direction is invalid.
*/
/*RuleBasedTransliterator::RuleBasedTransliterator(
const UnicodeString& id,
const UnicodeString& rules,
UTransDirection direction,
UnicodeFilter* adoptedFilter,
UErrorCode& status) :
Transliterator(id, adoptedFilter) {
UParseError parseError;
_construct(rules, direction,parseError, status);
}*/
/**
* Covenience constructor with no filter.
*/
/*RuleBasedTransliterator::RuleBasedTransliterator(
const UnicodeString& id,
const UnicodeString& rules,
UTransDirection direction,
UErrorCode& status) :
Transliterator(id, 0) {
UParseError parseError;
_construct(rules, direction,parseError, status);
}*/
/**
* Covenience constructor with no filter and FORWARD direction.
*/
/*RuleBasedTransliterator::RuleBasedTransliterator(
const UnicodeString& id,
const UnicodeString& rules,
UErrorCode& status) :
Transliterator(id, 0) {
UParseError parseError;
_construct(rules, UTRANS_FORWARD, parseError, status);
}*/
/**
* Covenience constructor with FORWARD direction.
*/
/*RuleBasedTransliterator::RuleBasedTransliterator(
const UnicodeString& id,
const UnicodeString& rules,
UnicodeFilter* adoptedFilter,
UErrorCode& status) :
Transliterator(id, adoptedFilter) {
UParseError parseError;
_construct(rules, UTRANS_FORWARD,parseError, status);
}*/
RuleBasedTransliterator::RuleBasedTransliterator(const UnicodeString& id,
const TransliterationRuleData* theData,
UnicodeFilter* adoptedFilter) :
Transliterator(id, adoptedFilter),
fData((TransliterationRuleData*)theData), // cast away const
isDataOwned(FALSE) {
setMaximumContextLength(fData->ruleSet.getMaximumContextLength());
}
/**
* Internal constructor.
*/
RuleBasedTransliterator::RuleBasedTransliterator(const UnicodeString& id,
TransliterationRuleData* theData,
UBool isDataAdopted) :
Transliterator(id, 0),
fData(theData),
isDataOwned(isDataAdopted) {
setMaximumContextLength(fData->ruleSet.getMaximumContextLength());
}
/**
* Copy constructor.
*/
RuleBasedTransliterator::RuleBasedTransliterator(
const RuleBasedTransliterator& other) :
Transliterator(other), fData(other.fData),
isDataOwned(other.isDataOwned) {
// The data object may or may not be owned. If it is not owned we
// share it; it is invariant. If it is owned, it's still
// invariant, but we need to copy it to prevent double-deletion.
// If this becomes a performance issue (if people do a lot of RBT
// copying -- unlikely) we can reference count the data object.
// Only do a deep copy if this is owned data, that is, data that
// will be later deleted. System transliterators contain
// non-owned data.
if (isDataOwned) {
fData = new TransliterationRuleData(*other.fData);
}
}
/**
* Destructor.
*/
RuleBasedTransliterator::~RuleBasedTransliterator() {
// Delete the data object only if we own it.
if (isDataOwned) {
delete fData;
}
}
Transliterator* // Covariant return NOT ALLOWED (for portability)
RuleBasedTransliterator::clone(void) const {
return new RuleBasedTransliterator(*this);
}
/**
* Implements {@link Transliterator#handleTransliterate}.
*/
void
RuleBasedTransliterator::handleTransliterate(Replaceable& text, UTransPosition& index,
UBool isIncremental) const {
/* We keep contextStart and contextLimit fixed the entire time,
* relative to the text -- contextLimit may move numerically if
* text is inserted or removed. The start offset moves toward
* limit, with replacements happening under it.
*
* Example: rules 1. ab>x|y
* 2. yc>z
*
* |eabcd begin - no match, advance start
* e|abcd match rule 1 - change text & adjust start
* ex|ycd match rule 2 - change text & adjust start
* exz|d no match, advance start
* exzd| done
*/
/* A rule like
* a>b|a
* creates an infinite loop. To prevent that, we put an arbitrary
* limit on the number of iterations that we take, one that is
* high enough that any reasonable rules are ok, but low enough to
* prevent a server from hanging. The limit is 16 times the
* number of characters n, unless n is so large that 16n exceeds a
* uint32_t.
*/
uint32_t loopCount = 0;
uint32_t loopLimit = index.limit - index.start;
if (loopLimit >= 0x10000000) {
loopLimit = 0xFFFFFFFF;
} else {
loopLimit <<= 4;
}
// Transliterator locking. Rule-based Transliterators are not thread safe; concurrent
// operations must be prevented.
// A Complication: compound transliterators can result in recursive entries to this
// function, sometimes with different "This" objects, always with the same text.
// Double-locking must be prevented in these cases.
//
// If the transliteration data is exclusively owned by this transliterator object,
// we don't need to do any locking. No sharing between transliterators is possible,
// so no concurrent access from multiple threads is possible.
UBool lockedMutexAtThisLevel = FALSE;
if (isDataOwned == FALSE) {
// Test whether this request is operating on the same text string as some
// some other transliteration that is still in progress and holding the
// transliteration mutex. If so, do not lock the transliteration
// mutex again.
UBool needToLock;
UMTX_CHECK(NULL, (&text != gLockedText), needToLock);
if (needToLock) {
umtx_lock(&transliteratorDataMutex);
gLockedText = &text;
lockedMutexAtThisLevel = TRUE;
}
}
// Check to make sure we don't dereference a null pointer.
if (fData != NULL) {
while (index.start < index.limit &&
loopCount <= loopLimit &&
fData->ruleSet.transliterate(text, index, isIncremental)) {
++loopCount;
}
}
if (lockedMutexAtThisLevel) {
gLockedText = NULL;
umtx_unlock(&transliteratorDataMutex);
}
}
UnicodeString& RuleBasedTransliterator::toRules(UnicodeString& rulesSource,
UBool escapeUnprintable) const {
return fData->ruleSet.toRules(rulesSource, escapeUnprintable);
}
/**
* Implement Transliterator framework
*/
void RuleBasedTransliterator::handleGetSourceSet(UnicodeSet& result) const {
fData->ruleSet.getSourceTargetSet(result, FALSE);
}
/**
* Override Transliterator framework
*/
UnicodeSet& RuleBasedTransliterator::getTargetSet(UnicodeSet& result) const {
return fData->ruleSet.getSourceTargetSet(result, TRUE);
}
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_TRANSLITERATION */