156 lines
4.7 KiB
C++
156 lines
4.7 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 "hextouni.h"
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#include "rep.h"
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#include "unifilt.h"
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#include "unicode.h"
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/**
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* ID for this transliterator.
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*/
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const char* HexToUnicodeTransliterator::_ID = "Hex-Unicode";
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/**
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* Constructs a transliterator.
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*/
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HexToUnicodeTransliterator::HexToUnicodeTransliterator(UnicodeFilter* adoptedFilter) :
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Transliterator(_ID, adoptedFilter) {
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}
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/**
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* Copy constructor.
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*/
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HexToUnicodeTransliterator::HexToUnicodeTransliterator(const HexToUnicodeTransliterator& o) :
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Transliterator(o) {
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}
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/**
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* Assignment operator.
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*/
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HexToUnicodeTransliterator& HexToUnicodeTransliterator::operator=(
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const HexToUnicodeTransliterator& o) {
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Transliterator::operator=(o);
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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* HexToUnicodeTransliterator::clone() const {
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return new HexToUnicodeTransliterator(*this);
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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 HexToUnicodeTransliterator::transliterate(Replaceable& text,
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int32_t start, int32_t limit) const {
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int32_t offsets[3] = { start, limit, start };
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handleKeyboardTransliterate(text, offsets);
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return offsets[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 HexToUnicodeTransliterator::handleKeyboardTransliterate(Replaceable& text,
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int32_t offsets[3]) const {
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/**
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* Performs transliteration changing Unicode hexadecimal
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* escapes to characters. For example, "U+0040" -> '@'. A fixed
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* set of prefixes is recognized: "\u", "\U", "u+", "U+".
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*/
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int32_t cursor = offsets[CURSOR];
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int32_t limit = offsets[LIMIT];
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int32_t maxCursor = limit - 6;
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while (cursor <= maxCursor) {
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UChar c = filteredCharAt(text, cursor + 5);
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int32_t digit0 = Unicode::digit(c, 16);
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if (digit0 < 0) {
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if (c == '\\') {
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cursor += 5;
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} else if (c == 'U' || c == 'u' || c == '+') {
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cursor += 4;
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} else {
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cursor += 6;
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}
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continue;
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}
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int32_t u = digit0;
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bool_t toTop = FALSE;
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for (int32_t i=4; i>=2; --i) {
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c = filteredCharAt(text, cursor + i);
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int32_t digit = Unicode::digit(c, 16);
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if (digit < 0) {
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if (c == 'U' || c == 'u' || c == '+') {
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cursor += i-1;
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} else {
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cursor += 6;
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}
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toTop = TRUE; // This is a little awkward -- it was a "continue loop:"
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break; // statement in Java, where loop marked the while().
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} else {
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u |= digit << (4 * (5-i));
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}
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}
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if (toTop) {
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continue;
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}
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c = filteredCharAt(text, cursor);
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UChar d = filteredCharAt(text, cursor + 1);
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if (((c == 'U' || c == 'u') && d == '+')
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|| (c == '\\' && (d == 'U' || d == 'u'))) {
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// At this point, we have a match; replace cursor..cursor+5
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// with u.
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text.handleReplaceBetween(cursor, cursor+6, UnicodeString((UChar)u));
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limit -= 5;
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maxCursor -= 5;
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++cursor;
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} else {
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cursor += 6;
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}
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}
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offsets[LIMIT] = limit;
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offsets[CURSOR] = cursor;
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}
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UChar HexToUnicodeTransliterator::filteredCharAt(Replaceable& text, int32_t i) const {
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UChar c;
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const UnicodeFilter* filter = getFilter();
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return (filter == 0) ? text.charAt(i) :
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(filter->isIn(c = text.charAt(i)) ? c : (UChar)0xFFFF);
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}
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/**
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* Return the length of the longest context required by this transliterator.
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* This is <em>preceding</em> context.
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* @param direction either <code>FORWARD</code> or <code>REVERSE</code>
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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 HexToUnicodeTransliterator::getMaximumContextLength() const {
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return 0;
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}
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