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/*******************************************************************************
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* THIS FILE IS INCLUDED IN TAGLIB, BUT IS NOT COPYRIGHTED BY THE TAGLIB *
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* AUTHORS, NOT PART OF THE TAGLIB API AND COULD GO AWAY AT ANY POINT IN TIME. *
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* AS SUCH IT SHOULD BE CONSIERED FOR INTERNAL USE ONLY. *
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*******************************************************************************/
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* Copyright 2001 Unicode, Inc.
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* This source code is provided as is by Unicode, Inc. No claims are
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* made as to fitness for any particular purpose. No warranties of any
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* kind are expressed or implied. The recipient agrees to determine
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* applicability of information provided. If this file has been
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* purchased on magnetic or optical media from Unicode, Inc., the
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* sole remedy for any claim will be exchange of defective media
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* within 90 days of receipt.
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* Limitations on Rights to Redistribute This Code
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* Unicode, Inc. hereby grants the right to freely use the information
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* supplied in this file in the creation of products supporting the
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* Unicode Standard, and to make copies of this file in any form
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* for internal or external distribution as long as this notice
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* This file has been modified by Scott Wheeler <wheeler@kde.org> to remove
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* the UTF32 conversion functions and to place the appropriate functions
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* in their own C++ namespace.
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/* ---------------------------------------------------------------------
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Conversions between UTF32, UTF-16, and UTF-8. Source code file.
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Author: Mark E. Davis, 1994.
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Rev History: Rick McGowan, fixes & updates May 2001.
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Sept 2001: fixed const & error conditions per
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mods suggested by S. Parent & A. Lillich.
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See the header file "ConvertUTF.h" for complete documentation.
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------------------------------------------------------------------------ */
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#define UNI_SUR_HIGH_START (UTF32)0xD800
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#define UNI_SUR_HIGH_END (UTF32)0xDBFF
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#define UNI_SUR_LOW_START (UTF32)0xDC00
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#define UNI_SUR_LOW_END (UTF32)0xDFFF
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static const int halfShift = 10; /* used for shifting by 10 bits */
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static const UTF32 halfBase = 0x0010000UL;
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static const UTF32 halfMask = 0x3FFUL;
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* Index into the table below with the first byte of a UTF-8 sequence to
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* get the number of trailing bytes that are supposed to follow it.
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static const char trailingBytesForUTF8[256] = {
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5
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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 UTF32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL,
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0x03C82080UL, 0xFA082080UL, 0x82082080UL };
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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... six byte sequence.)
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static const UTF8 firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
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/* --------------------------------------------------------------------- */
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/* The interface converts a whole buffer to avoid function-call overhead.
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* Constants have been gathered. Loops & conditionals have been removed as
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* much as possible for efficiency, in favor of drop-through switches.
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* (See "Note A" at the bottom of the file for equivalent code.)
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* If your compiler supports it, the "isLegalUTF8" call can be turned
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* into an inline function.
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/* --------------------------------------------------------------------- */
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ConversionResult ConvertUTF16toUTF8 (
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const UTF16** sourceStart, const UTF16* sourceEnd,
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UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
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ConversionResult result = conversionOK;
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const UTF16* source = *sourceStart;
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UTF8* target = *targetStart;
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while (source < sourceEnd) {
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unsigned short bytesToWrite = 0;
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const UTF32 byteMask = 0xBF;
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const UTF32 byteMark = 0x80;
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const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
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/* If we have a surrogate pair, convert to UTF32 first. */
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if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END && source < sourceEnd) {
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if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
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ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
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+ (ch2 - UNI_SUR_LOW_START) + halfBase;
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} else if (flags == strictConversion) { /* 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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} else if ((flags == strictConversion) && (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END)) {
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--source; /* return to the illegal value itself */
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result = sourceIllegal;
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/* Figure out how many bytes the result will require */
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if (ch < (UTF32)0x80) { bytesToWrite = 1;
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} else if (ch < (UTF32)0x800) { bytesToWrite = 2;
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} else if (ch < (UTF32)0x10000) { bytesToWrite = 3;
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} else if (ch < (UTF32)0x200000) { bytesToWrite = 4;
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} else { bytesToWrite = 2;
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ch = UNI_REPLACEMENT_CHAR;
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// printf("bytes to write = %i\n", bytesToWrite);
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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; result = targetExhausted; break;
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switch (bytesToWrite) { /* note: everything falls through. */
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case 4: *--target = (ch | byteMark) & byteMask; ch >>= 6;
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case 3: *--target = (ch | byteMark) & byteMask; ch >>= 6;
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case 2: *--target = (ch | byteMark) & byteMask; ch >>= 6;
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case 1: *--target = ch | firstByteMark[bytesToWrite];
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target += bytesToWrite;
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*sourceStart = source;
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*targetStart = target;
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/* --------------------------------------------------------------------- */
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* Utility routine to tell whether a sequence of bytes is legal UTF-8.
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* This must be called with the length pre-determined by the first byte.
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* If not calling this from ConvertUTF8to*, then the length can be set by:
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* length = trailingBytesForUTF8[*source]+1;
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* and the sequence is illegal right away if there aren't that many bytes
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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 Boolean isLegalUTF8(const UTF8 *source, int length) {
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const UTF8 *srcptr = source+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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/* no fall-through in this inner switch */
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case 0xE0: if (a < 0xA0) 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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case 1: if (*source >= 0x80 && *source < 0xC2) return false;
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if (*source > 0xF4) return false;
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/* --------------------------------------------------------------------- */
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* Exported function to return whether a UTF-8 sequence is legal or not.
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* This is not used here; it's just exported.
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Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd) {
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int length = trailingBytesForUTF8[*source]+1;
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if (source+length > sourceEnd) {
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return isLegalUTF8(source, length);
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/* --------------------------------------------------------------------- */
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ConversionResult ConvertUTF8toUTF16 (
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const UTF8** sourceStart, const UTF8* sourceEnd,
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UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
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ConversionResult result = conversionOK;
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const UTF8* source = *sourceStart;
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UTF16* target = *targetStart;
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while (source < sourceEnd) {
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unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
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if (source + extraBytesToRead >= sourceEnd) {
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result = sourceExhausted; break;
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/* Do this check whether lenient or strict */
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if (! isLegalUTF8(source, extraBytesToRead+1)) {
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result = sourceIllegal;
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* The cases all fall through. See "Note A" below.
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switch (extraBytesToRead) {
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case 3: ch += *source++; ch <<= 6;
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case 2: ch += *source++; ch <<= 6;
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case 1: ch += *source++; ch <<= 6;
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case 0: ch += *source++;
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ch -= offsetsFromUTF8[extraBytesToRead];
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if (target >= targetEnd) {
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source -= (extraBytesToRead+1); /* Back up source pointer! */
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result = targetExhausted; break;
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if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
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if ((flags == strictConversion) && (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END)) {
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source -= (extraBytesToRead+1); /* return to the illegal value itself */
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result = sourceIllegal;
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*target++ = ch; /* normal case */
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} else if (ch > UNI_MAX_UTF16) {
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if (flags == strictConversion) {
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result = sourceIllegal;
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source -= (extraBytesToRead+1); /* return to the start */
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break; /* Bail out; shouldn't continue */
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*target++ = UNI_REPLACEMENT_CHAR;
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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 -= (extraBytesToRead+1); /* Back up source pointer! */
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result = targetExhausted; break;
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*target++ = (ch >> halfShift) + UNI_SUR_HIGH_START;
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*target++ = (ch & halfMask) + UNI_SUR_LOW_START;
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*sourceStart = source;
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*targetStart = target;
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/* ---------------------------------------------------------------------
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The fall-through switches in UTF-8 reading code save a
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temp variable, some decrements & conditionals. The switches
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are equivalent to the following loop:
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int tmpBytesToRead = extraBytesToRead+1;
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if (tmpBytesToRead) ch <<= 6;
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} while (tmpBytesToRead > 0);
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In UTF-8 writing code, the switches on "bytesToWrite" are
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similarly unrolled loops.
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--------------------------------------------------------------------- */
added
removed
Frameworks/taglib/taglib/taglib/toolkit/unicode.cpp
