278 lines
9.1 KiB
C++
278 lines
9.1 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 "cpdtrans.h"
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#include "unifilt.h"
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#include "unifltlg.h"
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CompoundTransliterator::CompoundTransliterator(const UnicodeString& ID,
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UnicodeFilter* adoptedFilter) :
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Transliterator(ID,adoptedFilter),
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trans(0), count(0) {
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}
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/**
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* Constructs a new compound transliterator given an array of
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* transliterators. The array of transliterators may be of any
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* length, including zero or one, however, useful compound
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* transliterators have at least two components.
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* @param transliterators array of <code>Transliterator</code>
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* objects
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* @param filter the filter. Any character for which
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* <tt>filter.isIn()</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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CompoundTransliterator::CompoundTransliterator(const UnicodeString& ID,
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Transliterator* const transliterators[],
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int32_t transCount,
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UnicodeFilter* adoptedFilter) :
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Transliterator(ID,adoptedFilter),
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trans(0), count(0) {
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setTransliterators(transliterators, transCount);
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}
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/**
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* Copy constructor.
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*/
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CompoundTransliterator::CompoundTransliterator(const CompoundTransliterator& t) :
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Transliterator(t), trans(0), count(0) {
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*this = t;
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}
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/**
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* Destructor
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*/
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CompoundTransliterator::~CompoundTransliterator() {
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freeTransliterators();
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}
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void CompoundTransliterator::freeTransliterators(void) {
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for (int32_t i=0; i<count; ++i) {
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delete trans[i];
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}
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delete[] trans;
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trans = 0;
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count = 0;
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}
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/**
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* Assignment operator.
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*/
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CompoundTransliterator& CompoundTransliterator::operator=(
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const CompoundTransliterator& t) {
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Transliterator::operator=(t);
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int32_t i;
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for (i=0; i<count; ++i) {
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delete trans[i];
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trans[i] = 0;
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}
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if (t.count > count) {
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delete[] trans;
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trans = new Transliterator*[t.count];
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}
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count = t.count;
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for (i=0; i<count; ++i) {
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trans[i] = t.trans[i]->clone();
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}
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return *this;
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}
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/**
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* Transliterator API.
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*/
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Transliterator* CompoundTransliterator::clone(void) const {
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return new CompoundTransliterator(*this);
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}
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/**
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* Returns the number of transliterators in this chain.
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* @return number of transliterators in this chain.
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*/
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int32_t CompoundTransliterator::getCount(void) const {
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return count;
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}
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/**
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* Returns the transliterator at the given index in this chain.
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* @param index index into chain, from 0 to <code>getCount() - 1</code>
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* @return transliterator at the given index
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*/
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const Transliterator& CompoundTransliterator::getTransliterator(int32_t index) const {
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return *trans[index];
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}
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void CompoundTransliterator::setTransliterators(Transliterator* const transliterators[],
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int32_t transCount) {
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Transliterator** a = new Transliterator*[transCount];
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for (int32_t i=0; i<transCount; ++i) {
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a[i] = transliterators[i]->clone();
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}
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adoptTransliterators(a, transCount);
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}
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void CompoundTransliterator::adoptTransliterators(Transliterator* adoptedTransliterators[],
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int32_t transCount) {
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freeTransliterators();
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trans = adoptedTransliterators;
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count = transCount;
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}
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/**
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* Transliterates a segment of a string. <code>Transliterator</code> API.
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* @param text the string to be transliterated
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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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* @return the new limit index
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*/
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int32_t CompoundTransliterator::transliterate(Replaceable& text,
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int32_t start, int32_t limit) const {
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for (int32_t i=0; i<count; ++i) {
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limit = trans[i]->transliterate(text, start, limit);
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}
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return limit;
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}
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/**
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* Implements {@link Transliterator#handleKeyboardTransliterate}.
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*/
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void CompoundTransliterator::handleKeyboardTransliterate(Replaceable& text,
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int32_t index[3]) const {
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/* Call each transliterator with the same start value and
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* initial cursor index, but with the limit index as modified
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* by preceding transliterators. The cursor index must be
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* reset for each transliterator to give each a chance to
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* transliterate the text. The initial cursor index is known
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* to still point to the same place after each transliterator
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* is called because each transliterator will not change the
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* text between start and the initial value of cursor.
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*
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* IMPORTANT: After the first transliterator, each subsequent
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* transliterator only gets to transliterate text committed by
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* preceding transliterators; that is, the cursor (output
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* value) of transliterator i becomes the limit (input value)
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* of transliterator i+1. Finally, the overall limit is fixed
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* up before we return.
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*
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* Assumptions we make here:
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* (1) start <= cursor <= limit ;cursor valid on entry
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* (2) cursor <= cursor' <= limit' ;cursor doesn't move back
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* (3) cursor <= limit' ;text before cursor unchanged
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* - cursor' is the value of cursor after calling handleKT
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* - limit' is the value of limit after calling handleKT
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*/
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/**
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* Example: 3 transliterators. This example illustrates the
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* mechanics we need to implement. S, C, and L are the start,
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* cursor, and limit. gl is the globalLimit.
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*
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* 1. h-u, changes hex to Unicode
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*
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* 4 7 a d 0 4 7 a
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* abc/u0061/u => abca/u
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* S C L S C L gl=f->a
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*
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* 2. upup, changes "x" to "XX"
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*
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* 4 7 a 4 7 a
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* abca/u => abcAA/u
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* S CL S C
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* L gl=a->b
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* 3. u-h, changes Unicode to hex
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*
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* 4 7 a 4 7 a d 0 3
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* abcAA/u => abc/u0041/u0041/u
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* S C L S C
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* L gl=b->15
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* 4. return
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*
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* 4 7 a d 0 3
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* abc/u0041/u0041/u
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* S C L
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*/
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if (count < 1) {
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return; // Short circuit for empty compound transliterators
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}
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/**
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* One more wrinkle. If there is a filter F for the compound
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* transliterator as a whole, then we need to modify every
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* non-null filter f in the chain to be f' = F & f. Then,
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* when we're done, we restore the original filters.
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*
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* A possible future optimization is to change f to f' at
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* construction time, but then if anyone else is using the
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* transliterators in the chain outside of this context, they
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* will get unexpected results.
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*/
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const UnicodeFilter* F = getFilter();
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UnicodeFilter** f = 0;
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if (F != 0) {
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f = new UnicodeFilter*[count];
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for (int32_t i=0; i<count; ++i) {
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f[i] = trans[i]->getFilter()->clone();
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trans[i]->adoptFilter(UnicodeFilterLogic::createAnd(*F, *f[i]));
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}
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}
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int32_t cursor = index[CURSOR];
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int32_t limit = index[LIMIT];
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int32_t globalLimit = limit;
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/* globalLimit is the overall limit. We keep track of this
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* since we overwrite index[LIMIT] with the previous
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* index[CURSOR]. After each transliteration, we update
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* globalLimit for insertions or deletions that have happened.
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*/
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for (int32_t i=0; i<count; ++i) {
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index[CURSOR] = cursor; // Reset cursor
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index[LIMIT] = limit;
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trans[i]->handleKeyboardTransliterate(text, index);
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// Adjust overall limit for insertions/deletions
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globalLimit += index[LIMIT] - limit;
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limit = index[CURSOR]; // Move limit to end of committed text
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}
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// Cursor is good where it is -- where the last
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// transliterator left it. Limit needs to be put back
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// where it was, modulo adjustments for deletions/insertions.
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index[LIMIT] = globalLimit;
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// Fixup the transliterator filters, if we had to modify them.
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if (f != 0) {
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for (int32_t i=0; i<count; ++i) {
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trans[i]->adoptFilter(f[i]);
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}
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delete[] f;
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}
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}
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/**
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* Returns the length of the longest context required by this transliterator.
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* This is <em>preceding</em> context.
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* @return maximum number of preceding context characters this
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* transliterator needs to examine
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*/
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int32_t CompoundTransliterator::getMaximumContextLength(void) const {
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int32_t max = 0;
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for (int32_t i=0; i<count; ++i) {
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int32_t len = trans[i]->getMaximumContextLength();
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if (len > max) {
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max = len;
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}
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}
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return max;
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}
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