scuffed-code/icu4c/source/i18n/rbt_set.cpp
2001-11-06 05:07:06 +00:00

300 lines
10 KiB
C++

/*
**********************************************************************
* Copyright (C) 1999, International Business Machines
* Corporation and others. All Rights Reserved.
**********************************************************************
* Date Name Description
* 11/17/99 aliu Creation.
**********************************************************************
*/
#include "rbt_set.h"
#include "rbt_rule.h"
#include "unicode/unistr.h"
#include "cmemory.h"
U_CDECL_BEGIN
static void U_CALLCONV _deleteRule(void *rule) {
delete (U_NAMESPACE_QUALIFIER TransliterationRule *)rule;
}
U_CDECL_END
// Fill the precontext and postcontext with the patterns of the rules
// that are masking one another.
static void maskingError(const U_NAMESPACE_QUALIFIER TransliterationRule& rule1,
const U_NAMESPACE_QUALIFIER TransliterationRule& rule2,
UParseError& parseError) {
U_NAMESPACE_QUALIFIER UnicodeString r;
int32_t len;
parseError.line = 0;
parseError.offset = 0;
// for pre-context
rule1.toRule(r, FALSE);
len = uprv_min(r.length(), U_PARSE_CONTEXT_LEN-1);
r.extract(0, len, parseError.preContext);
parseError.preContext[len] = 0;
//for post-context
r.truncate(0);
rule2.toRule(r, FALSE);
len = uprv_min(r.length(), U_PARSE_CONTEXT_LEN-1);
r.extract(0, len, parseError.postContext);
parseError.postContext[len] = 0;
}
U_NAMESPACE_BEGIN
/**
* Construct a new empty rule set.
*/
TransliterationRuleSet::TransliterationRuleSet(UErrorCode& status) {
ruleVector = new UVector(&_deleteRule, NULL, status);
rules = NULL;
maxContextLength = 0;
if (ruleVector == NULL) {
status = U_MEMORY_ALLOCATION_ERROR;
}
}
/**
* Copy constructor.
*/
TransliterationRuleSet::TransliterationRuleSet(const TransliterationRuleSet& other) :
ruleVector(0),
rules(0),
maxContextLength(other.maxContextLength) {
int32_t i, len;
uprv_memcpy(index, other.index, sizeof(index));
UErrorCode status = U_ZERO_ERROR;
ruleVector = new UVector(&_deleteRule, NULL, status);
if (other.ruleVector != 0 && ruleVector != 0 && U_SUCCESS(status)) {
len = other.ruleVector->size();
for (i=0; i<len && U_SUCCESS(status); ++i) {
ruleVector->addElement(new TransliterationRule(
*(TransliterationRule*)other.ruleVector->elementAt(i)), status);
}
}
if (other.rules != 0) {
UParseError p;
freeze(p, status);
}
}
/**
* Destructor.
*/
TransliterationRuleSet::~TransliterationRuleSet() {
delete ruleVector; // This deletes the contained rules
delete[] rules;
}
void TransliterationRuleSet::setData(const TransliterationRuleData* d) {
/**
* We assume that the ruleset has already been frozen.
*/
int32_t len = index[256]; // see freeze()
for (int32_t i=0; i<len; ++i) {
rules[i]->setData(d);
}
}
/**
* Return the maximum context length.
* @return the length of the longest preceding context.
*/
int32_t TransliterationRuleSet::getMaximumContextLength(void) const {
return maxContextLength;
}
/**
* Add a rule to this set. Rules are added in order, and order is
* significant. The last call to this method must be followed by
* a call to <code>freeze()</code> before the rule set is used.
*
* <p>If freeze() has already been called, calling addRule()
* unfreezes the rules, and freeze() must be called again.
*
* @param adoptedRule the rule to add
*/
void TransliterationRuleSet::addRule(TransliterationRule* adoptedRule,
UErrorCode& status) {
if (U_FAILURE(status)) {
delete adoptedRule;
return;
}
ruleVector->addElement(adoptedRule, status);
int32_t len;
if ((len = adoptedRule->getContextLength()) > maxContextLength) {
maxContextLength = len;
}
delete rules;
rules = 0;
}
/**
* Check this for masked rules and index it to optimize performance.
* The sequence of operations is: (1) add rules to a set using
* <code>addRule()</code>; (2) freeze the set using
* <code>freeze()</code>; (3) use the rule set. If
* <code>addRule()</code> is called after calling this method, it
* invalidates this object, and this method must be called again.
* That is, <code>freeze()</code> may be called multiple times,
* although for optimal performance it shouldn't be.
*/
void TransliterationRuleSet::freeze(UParseError& parseError,UErrorCode& status) {
/* Construct the rule array and index table. We reorder the
* rules by sorting them into 256 bins. Each bin contains all
* rules matching the index value for that bin. A rule
* matches an index value if string whose first key character
* has a low byte equal to the index value can match the rule.
*
* Each bin contains zero or more rules, in the same order
* they were found originally. However, the total rules in
* the bins may exceed the number in the original vector,
* since rules that have a variable as their first key
* character will generally fall into more than one bin.
*
* That is, each bin contains all rules that either have that
* first index value as their first key character, or have
* a set containing the index value as their first character.
*/
int32_t n = ruleVector->size();
int32_t j;
int16_t x;
UVector v(status, 2*n); // heuristic; adjust as needed
if (U_FAILURE(status)) {
return;
}
/* Precompute the index values. This saves a LOT of time.
*/
int16_t* indexValue = new int16_t[n];
for (j=0; j<n; ++j) {
TransliterationRule* r = (TransliterationRule*) ruleVector->elementAt(j);
indexValue[j] = r->getIndexValue();
}
for (x=0; x<256; ++x) {
index[x] = v.size();
for (j=0; j<n; ++j) {
if (indexValue[j] >= 0) {
if (indexValue[j] == x) {
v.addElement(ruleVector->elementAt(j), status);
}
} else {
// If the indexValue is < 0, then the first key character is
// a set, and we must use the more time-consuming
// matchesIndexValue check. In practice this happens
// rarely, so we seldom tread this code path.
TransliterationRule* r = (TransliterationRule*) ruleVector->elementAt(j);
if (r->matchesIndexValue((uint8_t)x)) {
v.addElement(r, status);
}
}
}
}
delete[] indexValue;
index[256] = v.size();
/* Freeze things into an array.
*/
delete[] rules; // Contains alias pointers
rules = new TransliterationRule*[v.size()];
for (j=0; j<v.size(); ++j) {
rules[j] = (TransliterationRule*) v.elementAt(j);
}
// TODO Add error reporting that indicates the rules that
// are being masked.
//UnicodeString errors;
/* Check for masking. This is MUCH faster than our old check,
* which was each rule against each following rule, since we
* only have to check for masking within each bin now. It's
* 256*O(n2^2) instead of O(n1^2), where n1 is the total rule
* count, and n2 is the per-bin rule count. But n2<<n1, so
* it's a big win.
*/
for (x=0; x<256; ++x) {
for (j=index[x]; j<index[x+1]-1; ++j) {
TransliterationRule* r1 = rules[j];
for (int32_t k=j+1; k<index[x+1]; ++k) {
TransliterationRule* r2 = rules[k];
if (r1->masks(*r2)) {
//| if (errors == null) {
//| errors = new StringBuffer();
//| } else {
//| errors.append("\n");
//| }
//| errors.append("Rule " + r1 + " masks " + r2);
status = U_RULE_MASK_ERROR;
maskingError(*r1, *r2, parseError);
return;
}
}
}
}
//if (errors != null) {
// throw new IllegalArgumentException(errors.toString());
//}
}
/**
* Transliterate the given text with the given UTransPosition
* indices. Return TRUE if the transliteration should continue
* or FALSE if it should halt (because of a U_PARTIAL_MATCH match).
* Note that FALSE is only ever returned if isIncremental is TRUE.
* @param text the text to be transliterated
* @param pos the position indices, which will be updated
* @param incremental if TRUE, assume new text may be inserted
* at index.limit, and return FALSE if thre is a partial match.
* @return TRUE unless a U_PARTIAL_MATCH has been obtained,
* indicating that transliteration should stop until more text
* arrives.
*/
UBool TransliterationRuleSet::transliterate(Replaceable& text,
UTransPosition& pos,
UBool incremental) {
int16_t indexByte = (int16_t) (text.char32At(pos.start) & 0xFF);
for (int32_t i=index[indexByte]; i<index[indexByte+1]; ++i) {
UMatchDegree m = rules[i]->matchAndReplace(text, pos, incremental);
switch (m) {
case U_MATCH:
return TRUE;
case U_PARTIAL_MATCH:
return FALSE;
default: /* Ram: added default to make GCC happy */
break;
}
}
// No match or partial match from any rule
pos.start += UTF_CHAR_LENGTH(text.char32At(pos.start));
return TRUE;
}
/**
* Create rule strings that represents this rule set.
*/
UnicodeString& TransliterationRuleSet::toRules(UnicodeString& ruleSource,
UBool escapeUnprintable) const {
int32_t i;
int32_t count = ruleVector->size();
ruleSource.truncate(0);
for (i=0; i<count; ++i) {
if (i != 0) {
ruleSource.append((UChar) 0x000A /*\n*/);
}
TransliterationRule *r =
(TransliterationRule*) ruleVector->elementAt(i);
r->toRule(ruleSource, escapeUnprintable);
}
return ruleSource;
}
U_NAMESPACE_END