416 lines
17 KiB
C++
416 lines
17 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 "rbt_rule.h"
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#include "unicode/rep.h"
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#include "rbt_data.h"
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#include "unicode/unifilt.h"
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#include "unicode/uniset.h"
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/**
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* Construct a new rule with the given input, output text, and other
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* attributes. A cursor position may be specified for the output text.
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* @param input input string, including key and optional ante and
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* post context
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* @param anteContextPos offset into input to end of ante context, or -1 if
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* none. Must be <= input.length() if not -1.
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* @param postContextPos offset into input to start of post context, or -1
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* if none. Must be <= input.length() if not -1, and must be >=
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* anteContextPos.
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* @param output output string
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* @param cursorPos offset into output at which cursor is located, or -1 if
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* none. If less than zero, then the cursor is placed after the
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* <code>output</code>; that is, -1 is equivalent to
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* <code>output.length()</code>. If greater than
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* <code>output.length()</code> then an exception is thrown.
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* @param adoptedSegs array of 2n integers. Each of n pairs consists of offset,
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* limit for a segment of the input string. Characters in the output string
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* refer to these segments if they are in a special range determined by the
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* associated RuleBasedTransliterator.Data object. May be null if there are
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* no segments.
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*/
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TransliterationRule::TransliterationRule(const UnicodeString& input,
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int32_t anteContextPos, int32_t postContextPos,
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const UnicodeString& output,
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int32_t cursorPos, int32_t cursorOffset,
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int32_t* adoptedSegs,
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UErrorCode& status) {
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init(input, anteContextPos, postContextPos,
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output, cursorPos, cursorOffset, adoptedSegs, status);
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}
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/**
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* Construct a new rule with the given input, output text, and other
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* attributes. A cursor position may be specified for the output text.
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* @param input input string, including key and optional ante and
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* post context
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* @param anteContextPos offset into input to end of ante context, or -1 if
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* none. Must be <= input.length() if not -1.
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* @param postContextPos offset into input to start of post context, or -1
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* if none. Must be <= input.length() if not -1, and must be >=
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* anteContextPos.
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* @param output output string
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* @param cursorPos offset into output at which cursor is located, or -1 if
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* none. If less than zero, then the cursor is placed after the
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* <code>output</code>; that is, -1 is equivalent to
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* <code>output.length()</code>. If greater than
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* <code>output.length()</code> then an exception is thrown.
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*/
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TransliterationRule::TransliterationRule(const UnicodeString& input,
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int32_t anteContextPos, int32_t postContextPos,
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const UnicodeString& output,
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int32_t cursorPos,
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UErrorCode& status) {
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init(input, anteContextPos, postContextPos,
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output, cursorPos, 0, NULL, status);
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}
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void TransliterationRule::init(const UnicodeString& input,
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int32_t anteContextPos, int32_t postContextPos,
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const UnicodeString& output,
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int32_t cursorPos, int32_t cursorOffset,
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int32_t* adoptedSegs,
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UErrorCode& status) {
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if (U_FAILURE(status)) {
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return;
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}
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// Do range checks only when warranted to save time
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if (anteContextPos < 0) {
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anteContextLength = 0;
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} else {
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if (anteContextPos > input.length()) {
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// throw new IllegalArgumentException("Invalid ante context");
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status = U_ILLEGAL_ARGUMENT_ERROR;
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return;
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}
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anteContextLength = anteContextPos;
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}
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if (postContextPos < 0) {
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keyLength = input.length() - anteContextLength;
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} else {
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if (postContextPos < anteContextLength ||
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postContextPos > input.length()) {
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// throw new IllegalArgumentException("Invalid post context");
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status = U_ILLEGAL_ARGUMENT_ERROR;
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return;
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}
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keyLength = postContextPos - anteContextLength;
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}
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if (cursorPos < 0) {
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cursorPos = output.length();
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} else {
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if (cursorPos > output.length()) {
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// throw new IllegalArgumentException("Invalid cursor position");
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status = U_ILLEGAL_ARGUMENT_ERROR;
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return;
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}
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}
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this->cursorPos = cursorPos + cursorOffset;
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pattern = input;
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this->output = output;
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// We don't validate the segments array. The caller must
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// guarantee that the segments are well-formed.
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this->segments = adoptedSegs;
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}
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TransliterationRule::~TransliterationRule() {
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delete[] segments;
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}
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/**
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* Return the position of the cursor within the output string.
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* @return a value from 0 to <code>getOutput().length()</code>, inclusive.
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*/
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int32_t TransliterationRule::getCursorPos(void) const {
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return cursorPos;
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}
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/**
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* Return the preceding context length. This method is needed to
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* support the <code>Transliterator</code> method
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* <code>getMaximumContextLength()</code>.
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*/
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int32_t TransliterationRule::getAnteContextLength(void) const {
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return anteContextLength;
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}
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/**
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* Internal method. Returns 8-bit index value for this rule.
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* This is the low byte of the first character of the key,
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* unless the first character of the key is a set. If it's a
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* set, or otherwise can match multiple keys, the index value is -1.
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*/
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int16_t TransliterationRule::getIndexValue(const TransliterationRuleData& data) const {
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if (anteContextLength == pattern.length()) {
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// A pattern with just ante context {such as foo)>bar} can
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// match any key.
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return -1;
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}
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UChar c = pattern.charAt(anteContextLength);
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return data.lookupSet(c) == NULL ? (c & 0xFF) : -1;
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}
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/**
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* Do a replacement of the input pattern with the output text in
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* the given string, at the given offset. This method assumes
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* that a match has already been found in the given text at the
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* given position.
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* @param text the text containing the substring to be replaced
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* @param offset the offset into the text at which the pattern
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* matches. This is the offset to the point after the ante
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* context, if any, and before the match string and any post
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* context.
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* @param data the RuleBasedTransliterator.Data object specifying
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* context for this transliterator.
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* @return the change in the length of the text
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*/
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int32_t TransliterationRule::replace(Replaceable& text, int32_t offset,
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const TransliterationRuleData& data) const {
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if (segments == NULL) {
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text.handleReplaceBetween(offset, offset + keyLength, output);
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return output.length() - keyLength;
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} else {
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/* When there are segments to be copied, use the Replaceable.copy()
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* API in order to retain out-of-band data. Copy everything to the
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* point after the key, then delete the key. That is, copy things
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* into offset + keyLength, then replace offset .. offset +
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* keyLength with the empty string.
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*
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* Minimize the number of calls to Replaceable.replace() and
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* Replaceable.copy().
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*/
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int32_t textStart = offset - anteContextLength;
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int32_t dest = offset + keyLength; // copy new text to here
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UnicodeString buf;
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for (int32_t i=0; i<output.length(); ++i) {
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UChar c = output.charAt(i);
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int32_t b = data.lookupSegmentReference(c);
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if (b < 0) {
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// Accumulate straight (non-segment) text.
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buf.append(c);
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} else {
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// Insert any accumulated straight text.
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if (buf.length() > 0) {
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text.handleReplaceBetween(dest, dest, buf);
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dest += buf.length();
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buf.remove();
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}
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// Copy segment with out-of-band data
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b *= 2;
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text.copy(textStart + segments[b],
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textStart + segments[b+1], dest);
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dest += segments[b+1] - segments[b];
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}
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}
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// Insert any accumulated straight text.
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if (buf.length() > 0) {
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text.handleReplaceBetween(dest, dest, buf);
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dest += buf.length();
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}
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// Delete the key
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buf.remove();
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text.handleReplaceBetween(offset, offset + keyLength, buf);
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return dest - (offset + keyLength) - keyLength;
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}
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}
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/**
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* Internal method. Returns true if this rule matches the given
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* index value. The index value is an 8-bit integer, 0..255,
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* representing the low byte of the first character of the key.
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* It matches this rule if it matches the first character of the
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* key, or if the first character of the key is a set, and the set
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* contains any character with a low byte equal to the index
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* value. If the rule contains only ante context, as in foo)>bar,
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* then it will match any key.
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*/
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UBool TransliterationRule::matchesIndexValue(uint8_t v,
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const TransliterationRuleData& data) const {
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if (anteContextLength == pattern.length()) {
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// A pattern with just ante context {such as foo)>bar} can
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// match any key.
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return TRUE;
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}
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UChar c = pattern.charAt(anteContextLength);
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const UnicodeSet* set = data.lookupSet(c);
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return set == NULL ? (uint8_t(c) == v) : set->containsIndexValue(v);
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}
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/**
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* Return true if this rule masks another rule. If r1 masks r2 then
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* r1 matches any input string that r2 matches. If r1 masks r2 and r2 masks
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* r1 then r1 == r2. Examples: "a>x" masks "ab>y". "a>x" masks "a[b]>y".
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* "[c]a>x" masks "[dc]a>y".
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*/
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UBool TransliterationRule::masks(const TransliterationRule& r2) const {
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/* Rule r1 masks rule r2 if the string formed of the
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* antecontext, key, and postcontext overlaps in the following
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* way:
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*
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* r1: aakkkpppp
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* r2: aaakkkkkpppp
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* ^
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*
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* The strings must be aligned at the first character of the
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* key. The length of r1 to the left of the alignment point
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* must be <= the length of r2 to the left; ditto for the
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* right. The characters of r1 must equal (or be a superset
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* of) the corresponding characters of r2. The superset
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* operation should be performed to check for UnicodeSet
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* masking.
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*/
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/* LIMITATION of the current mask algorithm: Some rule
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* maskings are currently not detected. For example,
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* "{Lu}]a>x" masks "A]a>y". This can be added later. TODO
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*/
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int32_t len = pattern.length();
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int32_t left = anteContextLength;
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int32_t left2 = r2.anteContextLength;
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int32_t right = len - left;
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int32_t right2 = r2.pattern.length() - left2;
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return left <= left2 && right <= right2 &&
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0 == r2.pattern.compare(left2 - left, len, pattern);
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}
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/**
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* Return true if this rule matches the given text.
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* @param text the text, both translated and untranslated
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* @param start the beginning index, inclusive; <code>0 <= start
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* <= limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit
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* <= text.length()</code>.
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* @param cursor position at which to translate next, representing offset
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* into text. This value must be between <code>start</code> and
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* <code>limit</code>.
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* @param filter the filter. Any character for which
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* <tt>filter.contains()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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*/
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UBool TransliterationRule::matches(const Replaceable& text,
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const UTransPosition& pos,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const {
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// Match anteContext, key, and postContext
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int32_t cursor = pos.start - anteContextLength;
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if (cursor < pos.contextStart ||
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(cursor + pattern.length()) > pos.contextLimit) {
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return FALSE;
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}
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for (int32_t i=0; i<pattern.length(); ++i, ++cursor) {
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if (!charMatches(pattern.charAt(i), text.charAt(cursor),
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data, filter)) {
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return FALSE;
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}
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}
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return TRUE;
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}
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/**
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* Return the degree of match between this rule and the given text. The
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* degree of match may be mismatch, a partial match, or a full match. A
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* mismatch means at least one character of the text does not match the
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* context or key. A partial match means some context and key characters
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* match, but the text is not long enough to match all of them. A full
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* match means all context and key characters match.
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* @param text the text, both translated and untranslated
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* @param start the beginning index, inclusive; <code>0 <= start
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* <= limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit
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* <= text.length()</code>.
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* @param cursor position at which to translate next, representing offset
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* into text. This value must be between <code>start</code> and
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* <code>limit</code>.
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* @param filter the filter. Any character for which
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* <tt>filter.contains()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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* @return one of <code>MISMATCH</code>, <code>PARTIAL_MATCH</code>, or
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* <code>FULL_MATCH</code>.
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* @see #MISMATCH
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* @see #PARTIAL_MATCH
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* @see #FULL_MATCH
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*/
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int32_t TransliterationRule::getMatchDegree(const Replaceable& text,
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const UTransPosition& pos,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const {
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int len = getRegionMatchLength(text, pos, pattern, data, filter);
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return len < anteContextLength ? MISMATCH :
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(len < pattern.length() ? PARTIAL_MATCH : FULL_MATCH);
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}
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/**
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* Return the number of characters of the text that match this rule. If
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* there is a mismatch, return -1. If the text is not long enough to match
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* any characters, return 0.
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* @param text the text, both translated and untranslated
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* @param start the beginning index, inclusive; <code>0 <= start
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* <= limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit
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* <= text.length()</code>.
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* @param cursor position at which to translate next, representing offset
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* into text. This value must be between <code>start</code> and
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* <code>limit</code>.
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* @param templ the text to match against. All characters must match.
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* @param data a dictionary of variables mapping <code>Character</code>
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* to <code>UnicodeSet</code>
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* @param filter the filter. Any character for which
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* <tt>filter.contains()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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* @return -1 if there is a mismatch, 0 if the text is not long enough to
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* match any characters, otherwise the number of characters of text that
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* match this rule.
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*/
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int32_t TransliterationRule::getRegionMatchLength(const Replaceable& text,
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const UTransPosition& pos,
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const UnicodeString& templ,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const {
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int32_t cursor = pos.start - anteContextLength;
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if (cursor < pos.contextStart) {
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return -1;
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}
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int32_t i;
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for (i=0; i<templ.length() && cursor<pos.contextLimit; ++i, ++cursor) {
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if (!charMatches(templ.charAt(i), text.charAt(cursor),
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data, filter)) {
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return -1;
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}
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}
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return i;
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}
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/**
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* Return true if the given key matches the given text. This method
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* accounts for the fact that the key character may represent a character
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* set. Note that the key and text characters may not be interchanged
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* without altering the results.
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* @param keyChar a character in the match key
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* @param textChar a character in the text being transliterated
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* @param data a dictionary of variables mapping <code>Character</code>
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* to <code>UnicodeSet</code>
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* @param filter the filter. Any character for which
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* <tt>filter.contains()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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*/
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UBool TransliterationRule::charMatches(UChar keyChar, UChar textChar,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const {
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const UnicodeSet* set = 0;
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return (filter == 0 || filter->contains(textChar)) &&
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(((set = data.lookupSet(keyChar)) == 0) ?
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keyChar == textChar : set->contains(textChar));
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}
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