scuffed-code/icu4c/source/i18n/hextouni.cpp

156 lines
4.7 KiB
C++

/*
**********************************************************************
* Copyright (C) 1999, International Business Machines
* Corporation and others. All Rights Reserved.
**********************************************************************
* Date Name Description
* 11/17/99 aliu Creation.
**********************************************************************
*/
#include "unicode/hextouni.h"
#include "unicode/rep.h"
#include "unicode/unifilt.h"
#include "unicode/unicode.h"
/**
* ID for this transliterator.
*/
const char* HexToUnicodeTransliterator::_ID = "Hex-Unicode";
/**
* Constructs a transliterator.
*/
HexToUnicodeTransliterator::HexToUnicodeTransliterator(UnicodeFilter* adoptedFilter) :
Transliterator(_ID, adoptedFilter) {
}
/**
* Copy constructor.
*/
HexToUnicodeTransliterator::HexToUnicodeTransliterator(const HexToUnicodeTransliterator& o) :
Transliterator(o) {
}
/**
* Assignment operator.
*/
HexToUnicodeTransliterator& HexToUnicodeTransliterator::operator=(
const HexToUnicodeTransliterator& o) {
Transliterator::operator=(o);
return *this;
}
/**
* Transliterator API.
*/
Transliterator* HexToUnicodeTransliterator::clone(void) const {
return new HexToUnicodeTransliterator(*this);
}
/**
* Transliterates a segment of a string. <code>Transliterator</code> API.
* @param text the string to be transliterated
* @param start the beginning index, inclusive; <code>0 <= start
* <= limit</code>.
* @param limit the ending index, exclusive; <code>start <= limit
* <= text.length()</code>.
* @return the new limit index
*/
int32_t HexToUnicodeTransliterator::transliterate(Replaceable& text,
int32_t start, int32_t limit) const {
int32_t offsets[3] = { start, limit, start };
handleKeyboardTransliterate(text, offsets);
return offsets[LIMIT];
}
/**
* Implements {@link Transliterator#handleKeyboardTransliterate}.
*/
void HexToUnicodeTransliterator::handleKeyboardTransliterate(Replaceable& text,
int32_t offsets[3]) const {
/**
* Performs transliteration changing Unicode hexadecimal
* escapes to characters. For example, "U+0040" -> '@'. A fixed
* set of prefixes is recognized: "&#92;u", "&#92;U", "u+", "U+".
*/
int32_t cursor = offsets[CURSOR];
int32_t limit = offsets[LIMIT];
int32_t maxCursor = limit - 6;
while (cursor <= maxCursor) {
UChar c = filteredCharAt(text, cursor + 5);
int32_t digit0 = Unicode::digit(c, 16);
if (digit0 < 0) {
if (c == '\\') {
cursor += 5;
} else if (c == 'U' || c == 'u' || c == '+') {
cursor += 4;
} else {
cursor += 6;
}
continue;
}
int32_t u = digit0;
bool_t toTop = FALSE;
for (int32_t i=4; i>=2; --i) {
c = filteredCharAt(text, cursor + i);
int32_t digit = Unicode::digit(c, 16);
if (digit < 0) {
if (c == 'U' || c == 'u' || c == '+') {
cursor += i-1;
} else {
cursor += 6;
}
toTop = TRUE; // This is a little awkward -- it was a "continue loop:"
break; // statement in Java, where loop marked the while().
} else {
u |= digit << (4 * (5-i));
}
}
if (toTop) {
continue;
}
c = filteredCharAt(text, cursor);
UChar d = filteredCharAt(text, cursor + 1);
if (((c == 'U' || c == 'u') && d == '+')
|| (c == '\\' && (d == 'U' || d == 'u'))) {
// At this point, we have a match; replace cursor..cursor+5
// with u.
text.handleReplaceBetween(cursor, cursor+6, UnicodeString((UChar)u));
limit -= 5;
maxCursor -= 5;
++cursor;
} else {
cursor += 6;
}
}
offsets[LIMIT] = limit;
offsets[CURSOR] = cursor;
}
UChar HexToUnicodeTransliterator::filteredCharAt(Replaceable& text, int32_t i) const {
UChar c;
const UnicodeFilter* filter = getFilter();
return (filter == 0) ? text.charAt(i) :
(filter->isIn(c = text.charAt(i)) ? c : (UChar)0xFFFF);
}
/**
* Return the length of the longest context required by this transliterator.
* This is <em>preceding</em> context.
* @param direction either <code>FORWARD</code> or <code>REVERSE</code>
* @return maximum number of preceding context characters this
* transliterator needs to examine
*/
int32_t HexToUnicodeTransliterator::getMaximumContextLength(void) const {
return 0;
}