mirror of
https://github.com/flutter/flutter.git
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471 lines
16 KiB
C++
471 lines
16 KiB
C++
/*
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* Copyright (C) 2007 Apple Inc. All rights reserved.
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* Copyright (C) 2010 Patrick Gansterer <paroga@paroga.com>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "flutter/sky/engine/wtf/unicode/UTF8.h"
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#include "flutter/sky/engine/wtf/ASCIICType.h"
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#include "flutter/sky/engine/wtf/StringHasher.h"
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#include "flutter/sky/engine/wtf/unicode/CharacterNames.h"
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namespace WTF {
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namespace Unicode {
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inline int inlineUTF8SequenceLengthNonASCII(char b0)
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{
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if ((b0 & 0xC0) != 0xC0)
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return 0;
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if ((b0 & 0xE0) == 0xC0)
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return 2;
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if ((b0 & 0xF0) == 0xE0)
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return 3;
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if ((b0 & 0xF8) == 0xF0)
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return 4;
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return 0;
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}
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inline int inlineUTF8SequenceLength(char b0)
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{
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return isASCII(b0) ? 1 : inlineUTF8SequenceLengthNonASCII(b0);
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}
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int UTF8SequenceLength(char b0)
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{
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return isASCII(b0) ? 1 : inlineUTF8SequenceLengthNonASCII(b0);
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}
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int decodeUTF8Sequence(const char* sequence)
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{
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// Handle 0-byte sequences (never valid).
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const unsigned char b0 = sequence[0];
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const int length = inlineUTF8SequenceLength(b0);
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if (length == 0)
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return -1;
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// Handle 1-byte sequences (plain ASCII).
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const unsigned char b1 = sequence[1];
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if (length == 1) {
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if (b1)
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return -1;
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return b0;
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}
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// Handle 2-byte sequences.
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if ((b1 & 0xC0) != 0x80)
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return -1;
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const unsigned char b2 = sequence[2];
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if (length == 2) {
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if (b2)
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return -1;
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const int c = ((b0 & 0x1F) << 6) | (b1 & 0x3F);
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if (c < 0x80)
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return -1;
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return c;
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}
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// Handle 3-byte sequences.
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if ((b2 & 0xC0) != 0x80)
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return -1;
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const unsigned char b3 = sequence[3];
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if (length == 3) {
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if (b3)
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return -1;
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const int c = ((b0 & 0xF) << 12) | ((b1 & 0x3F) << 6) | (b2 & 0x3F);
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if (c < 0x800)
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return -1;
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// UTF-16 surrogates should never appear in UTF-8 data.
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if (c >= 0xD800 && c <= 0xDFFF)
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return -1;
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return c;
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}
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// Handle 4-byte sequences.
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if ((b3 & 0xC0) != 0x80)
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return -1;
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const unsigned char b4 = sequence[4];
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if (length == 4) {
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if (b4)
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return -1;
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const int c = ((b0 & 0x7) << 18) | ((b1 & 0x3F) << 12) | ((b2 & 0x3F) << 6) | (b3 & 0x3F);
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if (c < 0x10000 || c > 0x10FFFF)
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return -1;
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return c;
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}
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return -1;
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}
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// Once the bits are split out into bytes of UTF-8, this is a mask OR-ed
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// into the first byte, depending on how many bytes follow. There are
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// as many entries in this table as there are UTF-8 sequence types.
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// (I.e., one byte sequence, two byte... etc.). Remember that sequencs
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// for *legal* UTF-8 will be 4 or fewer bytes total.
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static const unsigned char firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
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ConversionResult convertLatin1ToUTF8(
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const LChar** sourceStart, const LChar* sourceEnd,
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char** targetStart, char* targetEnd)
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{
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ConversionResult result = conversionOK;
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const LChar* source = *sourceStart;
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char* target = *targetStart;
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while (source < sourceEnd) {
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UChar32 ch;
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unsigned short bytesToWrite = 0;
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const UChar32 byteMask = 0xBF;
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const UChar32 byteMark = 0x80;
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const LChar* oldSource = source; // In case we have to back up because of target overflow.
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ch = static_cast<unsigned short>(*source++);
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// Figure out how many bytes the result will require
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if (ch < (UChar32)0x80)
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bytesToWrite = 1;
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else
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bytesToWrite = 2;
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target += bytesToWrite;
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if (target > targetEnd) {
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source = oldSource; // Back up source pointer!
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target -= bytesToWrite;
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result = targetExhausted;
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break;
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}
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switch (bytesToWrite) { // note: everything falls through.
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case 2:
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*--target = (char)((ch | byteMark) & byteMask);
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ch >>= 6;
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case 1:
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*--target = (char)(ch | firstByteMark[bytesToWrite]);
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}
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target += bytesToWrite;
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}
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*sourceStart = source;
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*targetStart = target;
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return result;
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}
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ConversionResult convertUTF16ToUTF8(
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const UChar** sourceStart, const UChar* sourceEnd,
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char** targetStart, char* targetEnd, bool strict)
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{
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ConversionResult result = conversionOK;
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const UChar* source = *sourceStart;
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char* target = *targetStart;
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while (source < sourceEnd) {
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UChar32 ch;
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unsigned short bytesToWrite = 0;
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const UChar32 byteMask = 0xBF;
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const UChar32 byteMark = 0x80;
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const UChar* oldSource = source; // In case we have to back up because of target overflow.
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ch = static_cast<unsigned short>(*source++);
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// If we have a surrogate pair, convert to UChar32 first.
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if (ch >= 0xD800 && ch <= 0xDBFF) {
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// If the 16 bits following the high surrogate are in the source buffer...
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if (source < sourceEnd) {
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UChar32 ch2 = static_cast<unsigned short>(*source);
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// If it's a low surrogate, convert to UChar32.
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if (ch2 >= 0xDC00 && ch2 <= 0xDFFF) {
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ch = ((ch - 0xD800) << 10) + (ch2 - 0xDC00) + 0x0010000;
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++source;
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} else if (strict) { // it's an unpaired high surrogate
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--source; // return to the illegal value itself
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result = sourceIllegal;
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break;
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}
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} else { // We don't have the 16 bits following the high surrogate.
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--source; // return to the high surrogate
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result = sourceExhausted;
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break;
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}
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} else if (strict) {
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// UTF-16 surrogate values are illegal in UTF-32
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if (ch >= 0xDC00 && ch <= 0xDFFF) {
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--source; // return to the illegal value itself
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result = sourceIllegal;
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break;
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}
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}
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// Figure out how many bytes the result will require
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if (ch < (UChar32)0x80) {
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bytesToWrite = 1;
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} else if (ch < (UChar32)0x800) {
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bytesToWrite = 2;
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} else if (ch < (UChar32)0x10000) {
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bytesToWrite = 3;
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} else if (ch < (UChar32)0x110000) {
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bytesToWrite = 4;
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} else {
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bytesToWrite = 3;
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ch = replacementCharacter;
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}
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target += bytesToWrite;
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if (target > targetEnd) {
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source = oldSource; // Back up source pointer!
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target -= bytesToWrite;
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result = targetExhausted;
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break;
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}
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switch (bytesToWrite) { // note: everything falls through.
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case 4: *--target = (char)((ch | byteMark) & byteMask); ch >>= 6;
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case 3: *--target = (char)((ch | byteMark) & byteMask); ch >>= 6;
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case 2: *--target = (char)((ch | byteMark) & byteMask); ch >>= 6;
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case 1: *--target = (char)(ch | firstByteMark[bytesToWrite]);
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}
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target += bytesToWrite;
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}
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*sourceStart = source;
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*targetStart = target;
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return result;
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}
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// This must be called with the length pre-determined by the first byte.
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// If presented with a length > 4, this returns false. The Unicode
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// definition of UTF-8 goes up to 4-byte sequences.
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static bool isLegalUTF8(const unsigned char* source, int length)
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{
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unsigned char a;
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const unsigned char* srcptr = source + length;
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switch (length) {
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default: return false;
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// Everything else falls through when "true"...
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case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
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case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
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case 2: if ((a = (*--srcptr)) > 0xBF) return false;
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switch (*source) {
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// no fall-through in this inner switch
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case 0xE0: if (a < 0xA0) return false; break;
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case 0xED: if (a > 0x9F) return false; break;
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case 0xF0: if (a < 0x90) return false; break;
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case 0xF4: if (a > 0x8F) return false; break;
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default: if (a < 0x80) return false;
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}
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case 1: if (*source >= 0x80 && *source < 0xC2) return false;
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}
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if (*source > 0xF4)
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return false;
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return true;
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}
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// Magic values subtracted from a buffer value during UTF8 conversion.
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// This table contains as many values as there might be trailing bytes
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// in a UTF-8 sequence.
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static const UChar32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL, 0x03C82080UL, static_cast<UChar32>(0xFA082080UL), static_cast<UChar32>(0x82082080UL) };
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static inline UChar32 readUTF8Sequence(const char*& sequence, unsigned length)
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{
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UChar32 character = 0;
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// The cases all fall through.
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switch (length) {
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case 6: character += static_cast<unsigned char>(*sequence++); character <<= 6;
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case 5: character += static_cast<unsigned char>(*sequence++); character <<= 6;
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case 4: character += static_cast<unsigned char>(*sequence++); character <<= 6;
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case 3: character += static_cast<unsigned char>(*sequence++); character <<= 6;
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case 2: character += static_cast<unsigned char>(*sequence++); character <<= 6;
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case 1: character += static_cast<unsigned char>(*sequence++);
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}
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return character - offsetsFromUTF8[length - 1];
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}
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ConversionResult convertUTF8ToUTF16(
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const char** sourceStart, const char* sourceEnd,
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UChar** targetStart, UChar* targetEnd, bool* sourceAllASCII, bool strict)
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{
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ConversionResult result = conversionOK;
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const char* source = *sourceStart;
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UChar* target = *targetStart;
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UChar orAllData = 0;
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while (source < sourceEnd) {
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int utf8SequenceLength = inlineUTF8SequenceLength(*source);
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if (sourceEnd - source < utf8SequenceLength) {
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result = sourceExhausted;
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break;
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}
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// Do this check whether lenient or strict
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if (!isLegalUTF8(reinterpret_cast<const unsigned char*>(source), utf8SequenceLength)) {
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result = sourceIllegal;
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break;
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}
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UChar32 character = readUTF8Sequence(source, utf8SequenceLength);
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if (target >= targetEnd) {
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source -= utf8SequenceLength; // Back up source pointer!
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result = targetExhausted;
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break;
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}
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if (U_IS_BMP(character)) {
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// UTF-16 surrogate values are illegal in UTF-32
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if (U_IS_SURROGATE(character)) {
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if (strict) {
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source -= utf8SequenceLength; // return to the illegal value itself
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result = sourceIllegal;
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break;
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} else {
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*target++ = replacementCharacter;
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orAllData |= replacementCharacter;
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}
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} else {
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*target++ = character; // normal case
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orAllData |= character;
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}
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} else if (U_IS_SUPPLEMENTARY(character)) {
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// target is a character in range 0xFFFF - 0x10FFFF
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if (target + 1 >= targetEnd) {
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source -= utf8SequenceLength; // Back up source pointer!
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result = targetExhausted;
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break;
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}
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*target++ = U16_LEAD(character);
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*target++ = U16_TRAIL(character);
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orAllData = 0xffff;
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} else {
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if (strict) {
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source -= utf8SequenceLength; // return to the start
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result = sourceIllegal;
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break; // Bail out; shouldn't continue
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} else {
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*target++ = replacementCharacter;
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orAllData |= replacementCharacter;
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}
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}
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}
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*sourceStart = source;
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*targetStart = target;
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if (sourceAllASCII)
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*sourceAllASCII = !(orAllData & ~0x7f);
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return result;
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}
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unsigned calculateStringHashAndLengthFromUTF8MaskingTop8Bits(const char* data, const char* dataEnd, unsigned& dataLength, unsigned& utf16Length)
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{
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if (!data)
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return 0;
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StringHasher stringHasher;
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dataLength = 0;
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utf16Length = 0;
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while (data < dataEnd || (!dataEnd && *data)) {
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if (isASCII(*data)) {
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stringHasher.addCharacter(*data++);
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dataLength++;
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utf16Length++;
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continue;
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}
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int utf8SequenceLength = inlineUTF8SequenceLengthNonASCII(*data);
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dataLength += utf8SequenceLength;
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if (!dataEnd) {
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for (int i = 1; i < utf8SequenceLength; ++i) {
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if (!data[i])
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return 0;
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}
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} else if (dataEnd - data < utf8SequenceLength)
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return 0;
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if (!isLegalUTF8(reinterpret_cast<const unsigned char*>(data), utf8SequenceLength))
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return 0;
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UChar32 character = readUTF8Sequence(data, utf8SequenceLength);
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ASSERT(!isASCII(character));
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if (U_IS_BMP(character)) {
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// UTF-16 surrogate values are illegal in UTF-32
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if (U_IS_SURROGATE(character))
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return 0;
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stringHasher.addCharacter(static_cast<UChar>(character)); // normal case
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utf16Length++;
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} else if (U_IS_SUPPLEMENTARY(character)) {
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stringHasher.addCharacters(static_cast<UChar>(U16_LEAD(character)),
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static_cast<UChar>(U16_TRAIL(character)));
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utf16Length += 2;
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} else
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return 0;
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}
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return stringHasher.hashWithTop8BitsMasked();
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}
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template<typename CharType>
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ALWAYS_INLINE bool equalWithUTF8Internal(const CharType* a, const CharType* aEnd, const char* b, const char* bEnd)
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{
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while (b < bEnd) {
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if (isASCII(*b)) {
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if (*a++ != *b++)
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return false;
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continue;
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}
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int utf8SequenceLength = inlineUTF8SequenceLengthNonASCII(*b);
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if (bEnd - b < utf8SequenceLength)
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return false;
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if (!isLegalUTF8(reinterpret_cast<const unsigned char*>(b), utf8SequenceLength))
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return 0;
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UChar32 character = readUTF8Sequence(b, utf8SequenceLength);
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ASSERT(!isASCII(character));
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if (U_IS_BMP(character)) {
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// UTF-16 surrogate values are illegal in UTF-32
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if (U_IS_SURROGATE(character))
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return false;
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if (*a++ != character)
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return false;
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} else if (U_IS_SUPPLEMENTARY(character)) {
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if (*a++ != U16_LEAD(character))
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return false;
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if (*a++ != U16_TRAIL(character))
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return false;
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} else
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return false;
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}
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return a == aEnd;
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}
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bool equalUTF16WithUTF8(const UChar* a, const UChar* aEnd, const char* b, const char* bEnd)
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{
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return equalWithUTF8Internal(a, aEnd, b, bEnd);
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}
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bool equalLatin1WithUTF8(const LChar* a, const LChar* aEnd, const char* b, const char* bEnd)
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{
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return equalWithUTF8Internal(a, aEnd, b, bEnd);
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}
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} // namespace Unicode
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} // namespace WTF
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