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llvm-mirror/lib/Support/ConvertUTF.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo 
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

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/*===--- ConvertUTF.c - Universal Character Names conversions ---------------===
*
* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
* See https://llvm.org/LICENSE.txt for license information.
* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
*
*===------------------------------------------------------------------------=*/
/*
* Copyright 2001-2004 Unicode, Inc.
*
* Disclaimer
*
* This source code is provided as is by Unicode, Inc. No claims are
* made as to fitness for any particular purpose. No warranties of any
* kind are expressed or implied. The recipient agrees to determine
* applicability of information provided. If this file has been
* purchased on magnetic or optical media from Unicode, Inc., the
* sole remedy for any claim will be exchange of defective media
* within 90 days of receipt.
*
* Limitations on Rights to Redistribute This Code
*
* Unicode, Inc. hereby grants the right to freely use the information
* supplied in this file in the creation of products supporting the
* Unicode Standard, and to make copies of this file in any form
* for internal or external distribution as long as this notice
* remains attached.
*/
/* ---------------------------------------------------------------------
Conversions between UTF32, UTF-16, and UTF-8. Source code file.
Author: Mark E. Davis, 1994.
Rev History: Rick McGowan, fixes & updates May 2001.
Sept 2001: fixed const & error conditions per
mods suggested by S. Parent & A. Lillich.
June 2002: Tim Dodd added detection and handling of incomplete
source sequences, enhanced error detection, added casts
to eliminate compiler warnings.
July 2003: slight mods to back out aggressive FFFE detection.
Jan 2004: updated switches in from-UTF8 conversions.
Oct 2004: updated to use UNI_MAX_LEGAL_UTF32 in UTF-32 conversions.
See the header file "ConvertUTF.h" for complete documentation.
------------------------------------------------------------------------ */
#include "llvm/Support/ConvertUTF.h"
#ifdef CVTUTF_DEBUG
#include <stdio.h>
#endif
#include <assert.h>
/*
* This code extensively uses fall-through switches.
* Keep the compiler from warning about that.
*/
#if defined(__clang__) && defined(__has_warning)
# if __has_warning("-Wimplicit-fallthrough")
# define ConvertUTF_DISABLE_WARNINGS \
_Pragma("clang diagnostic push") \
_Pragma("clang diagnostic ignored \"-Wimplicit-fallthrough\"")
# define ConvertUTF_RESTORE_WARNINGS \
_Pragma("clang diagnostic pop")
# endif
#elif defined(__GNUC__) && __GNUC__ > 6
# define ConvertUTF_DISABLE_WARNINGS \
_Pragma("GCC diagnostic push") \
_Pragma("GCC diagnostic ignored \"-Wimplicit-fallthrough\"")
# define ConvertUTF_RESTORE_WARNINGS \
_Pragma("GCC diagnostic pop")
#endif
#ifndef ConvertUTF_DISABLE_WARNINGS
# define ConvertUTF_DISABLE_WARNINGS
#endif
#ifndef ConvertUTF_RESTORE_WARNINGS
# define ConvertUTF_RESTORE_WARNINGS
#endif
ConvertUTF_DISABLE_WARNINGS
namespace llvm {
static const int halfShift = 10; /* used for shifting by 10 bits */
static const UTF32 halfBase = 0x0010000UL;
static const UTF32 halfMask = 0x3FFUL;
#define UNI_SUR_HIGH_START (UTF32)0xD800
#define UNI_SUR_HIGH_END (UTF32)0xDBFF
#define UNI_SUR_LOW_START (UTF32)0xDC00
#define UNI_SUR_LOW_END (UTF32)0xDFFF
/* --------------------------------------------------------------------- */
/*
* Index into the table below with the first byte of a UTF-8 sequence to
* get the number of trailing bytes that are supposed to follow it.
* Note that *legal* UTF-8 values can't have 4 or 5-bytes. The table is
* left as-is for anyone who may want to do such conversion, which was
* allowed in earlier algorithms.
*/
static const char trailingBytesForUTF8[256] = {
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,
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,
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,
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,
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,
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,
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,
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
};
/*
* Magic values subtracted from a buffer value during UTF8 conversion.
* This table contains as many values as there might be trailing bytes
* in a UTF-8 sequence.
*/
static const UTF32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL,
0x03C82080UL, 0xFA082080UL, 0x82082080UL };
/*
* Once the bits are split out into bytes of UTF-8, this is a mask OR-ed
* into the first byte, depending on how many bytes follow. There are
* as many entries in this table as there are UTF-8 sequence types.
* (I.e., one byte sequence, two byte... etc.). Remember that sequencs
* for *legal* UTF-8 will be 4 or fewer bytes total.
*/
static const UTF8 firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
/* --------------------------------------------------------------------- */
/* The interface converts a whole buffer to avoid function-call overhead.
* Constants have been gathered. Loops & conditionals have been removed as
* much as possible for efficiency, in favor of drop-through switches.
* (See "Note A" at the bottom of the file for equivalent code.)
* If your compiler supports it, the "isLegalUTF8" call can be turned
* into an inline function.
*/
/* --------------------------------------------------------------------- */
ConversionResult ConvertUTF32toUTF16 (
const UTF32** sourceStart, const UTF32* sourceEnd,
UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
ConversionResult result = conversionOK;
const UTF32* source = *sourceStart;
UTF16* target = *targetStart;
while (source < sourceEnd) {
UTF32 ch;
if (target >= targetEnd) {
result = targetExhausted; break;
}
ch = *source++;
if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
/* UTF-16 surrogate values are illegal in UTF-32; 0xffff or 0xfffe are both reserved values */
if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
if (flags == strictConversion) {
--source; /* return to the illegal value itself */
result = sourceIllegal;
break;
} else {
*target++ = UNI_REPLACEMENT_CHAR;
}
} else {
*target++ = (UTF16)ch; /* normal case */
}
} else if (ch > UNI_MAX_LEGAL_UTF32) {
if (flags == strictConversion) {
result = sourceIllegal;
} else {
*target++ = UNI_REPLACEMENT_CHAR;
}
} else {
/* target is a character in range 0xFFFF - 0x10FFFF. */
if (target + 1 >= targetEnd) {
--source; /* Back up source pointer! */
result = targetExhausted; break;
}
ch -= halfBase;
*target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
*target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
}
}
*sourceStart = source;
*targetStart = target;
return result;
}
/* --------------------------------------------------------------------- */
ConversionResult ConvertUTF16toUTF32 (
const UTF16** sourceStart, const UTF16* sourceEnd,
UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
ConversionResult result = conversionOK;
const UTF16* source = *sourceStart;
UTF32* target = *targetStart;
UTF32 ch, ch2;
while (source < sourceEnd) {
const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
ch = *source++;
/* If we have a surrogate pair, convert to UTF32 first. */
if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) {
/* If the 16 bits following the high surrogate are in the source buffer... */
if (source < sourceEnd) {
ch2 = *source;
/* If it's a low surrogate, convert to UTF32. */
if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
+ (ch2 - UNI_SUR_LOW_START) + halfBase;
++source;
} else if (flags == strictConversion) { /* it's an unpaired high surrogate */
--source; /* return to the illegal value itself */
result = sourceIllegal;
break;
}
} else { /* We don't have the 16 bits following the high surrogate. */
--source; /* return to the high surrogate */
result = sourceExhausted;
break;
}
} else if (flags == strictConversion) {
/* UTF-16 surrogate values are illegal in UTF-32 */
if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
--source; /* return to the illegal value itself */
result = sourceIllegal;
break;
}
}
if (target >= targetEnd) {
source = oldSource; /* Back up source pointer! */
result = targetExhausted; break;
}
*target++ = ch;
}
*sourceStart = source;
*targetStart = target;
#ifdef CVTUTF_DEBUG
if (result == sourceIllegal) {
fprintf(stderr, "ConvertUTF16toUTF32 illegal seq 0x%04x,%04x\n", ch, ch2);
fflush(stderr);
}
#endif
return result;
}
ConversionResult ConvertUTF16toUTF8 (
const UTF16** sourceStart, const UTF16* sourceEnd,
UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
ConversionResult result = conversionOK;
const UTF16* source = *sourceStart;
UTF8* target = *targetStart;
while (source < sourceEnd) {
UTF32 ch;
unsigned short bytesToWrite = 0;
const UTF32 byteMask = 0xBF;
const UTF32 byteMark = 0x80;
const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
ch = *source++;
/* If we have a surrogate pair, convert to UTF32 first. */
if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) {
/* If the 16 bits following the high surrogate are in the source buffer... */
if (source < sourceEnd) {
UTF32 ch2 = *source;
/* If it's a low surrogate, convert to UTF32. */
if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
+ (ch2 - UNI_SUR_LOW_START) + halfBase;
++source;
} else if (flags == strictConversion) { /* it's an unpaired high surrogate */
--source; /* return to the illegal value itself */
result = sourceIllegal;
break;
}
} else { /* We don't have the 16 bits following the high surrogate. */
--source; /* return to the high surrogate */
result = sourceExhausted;
break;
}
} else if (flags == strictConversion) {
/* UTF-16 surrogate values are illegal in UTF-32 */
if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
--source; /* return to the illegal value itself */
result = sourceIllegal;
break;
}
}
/* Figure out how many bytes the result will require */
if (ch < (UTF32)0x80) { bytesToWrite = 1;
} else if (ch < (UTF32)0x800) { bytesToWrite = 2;
} else if (ch < (UTF32)0x10000) { bytesToWrite = 3;
} else if (ch < (UTF32)0x110000) { bytesToWrite = 4;
} else { bytesToWrite = 3;
ch = UNI_REPLACEMENT_CHAR;
}
target += bytesToWrite;
if (target > targetEnd) {
source = oldSource; /* Back up source pointer! */
target -= bytesToWrite; result = targetExhausted; break;
}
switch (bytesToWrite) { /* note: everything falls through. */
case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
case 1: *--target = (UTF8)(ch | firstByteMark[bytesToWrite]);
}
target += bytesToWrite;
}
*sourceStart = source;
*targetStart = target;
return result;
}
/* --------------------------------------------------------------------- */
ConversionResult ConvertUTF32toUTF8 (
const UTF32** sourceStart, const UTF32* sourceEnd,
UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
ConversionResult result = conversionOK;
const UTF32* source = *sourceStart;
UTF8* target = *targetStart;
while (source < sourceEnd) {
UTF32 ch;
unsigned short bytesToWrite = 0;
const UTF32 byteMask = 0xBF;
const UTF32 byteMark = 0x80;
ch = *source++;
if (flags == strictConversion ) {
/* UTF-16 surrogate values are illegal in UTF-32 */
if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
--source; /* return to the illegal value itself */
result = sourceIllegal;
break;
}
}
/*
* Figure out how many bytes the result will require. Turn any
* illegally large UTF32 things (> Plane 17) into replacement chars.
*/
if (ch < (UTF32)0x80) { bytesToWrite = 1;
} else if (ch < (UTF32)0x800) { bytesToWrite = 2;
} else if (ch < (UTF32)0x10000) { bytesToWrite = 3;
} else if (ch <= UNI_MAX_LEGAL_UTF32) { bytesToWrite = 4;
} else { bytesToWrite = 3;
ch = UNI_REPLACEMENT_CHAR;
result = sourceIllegal;
}
target += bytesToWrite;
if (target > targetEnd) {
--source; /* Back up source pointer! */
target -= bytesToWrite; result = targetExhausted; break;
}
switch (bytesToWrite) { /* note: everything falls through. */
case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
case 1: *--target = (UTF8) (ch | firstByteMark[bytesToWrite]);
}
target += bytesToWrite;
}
*sourceStart = source;
*targetStart = target;
return result;
}
/* --------------------------------------------------------------------- */
/*
* Utility routine to tell whether a sequence of bytes is legal UTF-8.
* This must be called with the length pre-determined by the first byte.
* If not calling this from ConvertUTF8to*, then the length can be set by:
* length = trailingBytesForUTF8[*source]+1;
* and the sequence is illegal right away if there aren't that many bytes
* available.
* If presented with a length > 4, this returns false. The Unicode
* definition of UTF-8 goes up to 4-byte sequences.
*/
static Boolean isLegalUTF8(const UTF8 *source, int length) {
UTF8 a;
const UTF8 *srcptr = source+length;
switch (length) {
default: return false;
/* Everything else falls through when "true"... */
case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
case 2: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
switch (*source) {
/* no fall-through in this inner switch */
case 0xE0: if (a < 0xA0) return false; break;
case 0xED: if (a > 0x9F) return false; break;
case 0xF0: if (a < 0x90) return false; break;
case 0xF4: if (a > 0x8F) return false; break;
default: if (a < 0x80) return false;
}
case 1: if (*source >= 0x80 && *source < 0xC2) return false;
}
if (*source > 0xF4) return false;
return true;
}
/* --------------------------------------------------------------------- */
/*
* Exported function to return whether a UTF-8 sequence is legal or not.
* This is not used here; it's just exported.
*/
Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd) {
int length = trailingBytesForUTF8[*source]+1;
if (length > sourceEnd - source) {
return false;
}
return isLegalUTF8(source, length);
}
/* --------------------------------------------------------------------- */
static unsigned
findMaximalSubpartOfIllFormedUTF8Sequence(const UTF8 *source,
const UTF8 *sourceEnd) {
UTF8 b1, b2, b3;
assert(!isLegalUTF8Sequence(source, sourceEnd));
/*
* Unicode 6.3.0, D93b:
*
* Maximal subpart of an ill-formed subsequence: The longest code unit
* subsequence starting at an unconvertible offset that is either:
* a. the initial subsequence of a well-formed code unit sequence, or
* b. a subsequence of length one.
*/
if (source == sourceEnd)
return 0;
/*
* Perform case analysis. See Unicode 6.3.0, Table 3-7. Well-Formed UTF-8
* Byte Sequences.
*/
b1 = *source;
++source;
if (b1 >= 0xC2 && b1 <= 0xDF) {
/*
* First byte is valid, but we know that this code unit sequence is
* invalid, so the maximal subpart has to end after the first byte.
*/
return 1;
}
if (source == sourceEnd)
return 1;
b2 = *source;
++source;
if (b1 == 0xE0) {
return (b2 >= 0xA0 && b2 <= 0xBF) ? 2 : 1;
}
if (b1 >= 0xE1 && b1 <= 0xEC) {
return (b2 >= 0x80 && b2 <= 0xBF) ? 2 : 1;
}
if (b1 == 0xED) {
return (b2 >= 0x80 && b2 <= 0x9F) ? 2 : 1;
}
if (b1 >= 0xEE && b1 <= 0xEF) {
return (b2 >= 0x80 && b2 <= 0xBF) ? 2 : 1;
}
if (b1 == 0xF0) {
if (b2 >= 0x90 && b2 <= 0xBF) {
if (source == sourceEnd)
return 2;
b3 = *source;
return (b3 >= 0x80 && b3 <= 0xBF) ? 3 : 2;
}
return 1;
}
if (b1 >= 0xF1 && b1 <= 0xF3) {
if (b2 >= 0x80 && b2 <= 0xBF) {
if (source == sourceEnd)
return 2;
b3 = *source;
return (b3 >= 0x80 && b3 <= 0xBF) ? 3 : 2;
}
return 1;
}
if (b1 == 0xF4) {
if (b2 >= 0x80 && b2 <= 0x8F) {
if (source == sourceEnd)
return 2;
b3 = *source;
return (b3 >= 0x80 && b3 <= 0xBF) ? 3 : 2;
}
return 1;
}
assert((b1 >= 0x80 && b1 <= 0xC1) || b1 >= 0xF5);
/*
* There are no valid sequences that start with these bytes. Maximal subpart
* is defined to have length 1 in these cases.
*/
return 1;
}
/* --------------------------------------------------------------------- */
/*
* Exported function to return the total number of bytes in a codepoint
* represented in UTF-8, given the value of the first byte.
*/
unsigned getNumBytesForUTF8(UTF8 first) {
return trailingBytesForUTF8[first] + 1;
}
/* --------------------------------------------------------------------- */
/*
* Exported function to return whether a UTF-8 string is legal or not.
* This is not used here; it's just exported.
*/
Boolean isLegalUTF8String(const UTF8 **source, const UTF8 *sourceEnd) {
while (*source != sourceEnd) {
int length = trailingBytesForUTF8[**source] + 1;
if (length > sourceEnd - *source || !isLegalUTF8(*source, length))
return false;
*source += length;
}
return true;
}
/* --------------------------------------------------------------------- */
ConversionResult ConvertUTF8toUTF16 (
const UTF8** sourceStart, const UTF8* sourceEnd,
UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
ConversionResult result = conversionOK;
const UTF8* source = *sourceStart;
UTF16* target = *targetStart;
while (source < sourceEnd) {
UTF32 ch = 0;
unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
if (extraBytesToRead >= sourceEnd - source) {
result = sourceExhausted; break;
}
/* Do this check whether lenient or strict */
if (!isLegalUTF8(source, extraBytesToRead+1)) {
result = sourceIllegal;
break;
}
/*
* The cases all fall through. See "Note A" below.
*/
switch (extraBytesToRead) {
case 5: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
case 4: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
case 3: ch += *source++; ch <<= 6;
case 2: ch += *source++; ch <<= 6;
case 1: ch += *source++; ch <<= 6;
case 0: ch += *source++;
}
ch -= offsetsFromUTF8[extraBytesToRead];
if (target >= targetEnd) {
source -= (extraBytesToRead+1); /* Back up source pointer! */
result = targetExhausted; break;
}
if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
/* UTF-16 surrogate values are illegal in UTF-32 */
if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
if (flags == strictConversion) {
source -= (extraBytesToRead+1); /* return to the illegal value itself */
result = sourceIllegal;
break;
} else {
*target++ = UNI_REPLACEMENT_CHAR;
}
} else {
*target++ = (UTF16)ch; /* normal case */
}
} else if (ch > UNI_MAX_UTF16) {
if (flags == strictConversion) {
result = sourceIllegal;
source -= (extraBytesToRead+1); /* return to the start */
break; /* Bail out; shouldn't continue */
} else {
*target++ = UNI_REPLACEMENT_CHAR;
}
} else {
/* target is a character in range 0xFFFF - 0x10FFFF. */
if (target + 1 >= targetEnd) {
source -= (extraBytesToRead+1); /* Back up source pointer! */
result = targetExhausted; break;
}
ch -= halfBase;
*target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
*target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
}
}
*sourceStart = source;
*targetStart = target;
return result;
}
/* --------------------------------------------------------------------- */
static ConversionResult ConvertUTF8toUTF32Impl(
const UTF8** sourceStart, const UTF8* sourceEnd,
UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags,
Boolean InputIsPartial) {
ConversionResult result = conversionOK;
const UTF8* source = *sourceStart;
UTF32* target = *targetStart;
while (source < sourceEnd) {
UTF32 ch = 0;
unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
if (extraBytesToRead >= sourceEnd - source) {
if (flags == strictConversion || InputIsPartial) {
result = sourceExhausted;
break;
} else {
result = sourceIllegal;
/*
* Replace the maximal subpart of ill-formed sequence with
* replacement character.
*/
source += findMaximalSubpartOfIllFormedUTF8Sequence(source,
sourceEnd);
*target++ = UNI_REPLACEMENT_CHAR;
continue;
}
}
if (target >= targetEnd) {
result = targetExhausted; break;
}
/* Do this check whether lenient or strict */
if (!isLegalUTF8(source, extraBytesToRead+1)) {
result = sourceIllegal;
if (flags == strictConversion) {
/* Abort conversion. */
break;
} else {
/*
* Replace the maximal subpart of ill-formed sequence with
* replacement character.
*/
source += findMaximalSubpartOfIllFormedUTF8Sequence(source,
sourceEnd);
*target++ = UNI_REPLACEMENT_CHAR;
continue;
}
}
/*
* The cases all fall through. See "Note A" below.
*/
switch (extraBytesToRead) {
case 5: ch += *source++; ch <<= 6;
case 4: ch += *source++; ch <<= 6;
case 3: ch += *source++; ch <<= 6;
case 2: ch += *source++; ch <<= 6;
case 1: ch += *source++; ch <<= 6;
case 0: ch += *source++;
}
ch -= offsetsFromUTF8[extraBytesToRead];
if (ch <= UNI_MAX_LEGAL_UTF32) {
/*
* UTF-16 surrogate values are illegal in UTF-32, and anything
* over Plane 17 (> 0x10FFFF) is illegal.
*/
if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
if (flags == strictConversion) {
source -= (extraBytesToRead+1); /* return to the illegal value itself */
result = sourceIllegal;
break;
} else {
*target++ = UNI_REPLACEMENT_CHAR;
}
} else {
*target++ = ch;
}
} else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */
result = sourceIllegal;
*target++ = UNI_REPLACEMENT_CHAR;
}
}
*sourceStart = source;
*targetStart = target;
return result;
}
ConversionResult ConvertUTF8toUTF32Partial(const UTF8 **sourceStart,
const UTF8 *sourceEnd,
UTF32 **targetStart,
UTF32 *targetEnd,
ConversionFlags flags) {
return ConvertUTF8toUTF32Impl(sourceStart, sourceEnd, targetStart, targetEnd,
flags, /*InputIsPartial=*/true);
}
ConversionResult ConvertUTF8toUTF32(const UTF8 **sourceStart,
const UTF8 *sourceEnd, UTF32 **targetStart,
UTF32 *targetEnd, ConversionFlags flags) {
return ConvertUTF8toUTF32Impl(sourceStart, sourceEnd, targetStart, targetEnd,
flags, /*InputIsPartial=*/false);
}
/* ---------------------------------------------------------------------
Note A.
The fall-through switches in UTF-8 reading code save a
temp variable, some decrements & conditionals. The switches
are equivalent to the following loop:
{
int tmpBytesToRead = extraBytesToRead+1;
do {
ch += *source++;
--tmpBytesToRead;
if (tmpBytesToRead) ch <<= 6;
} while (tmpBytesToRead > 0);
}
In UTF-8 writing code, the switches on "bytesToWrite" are
similarly unrolled loops.
--------------------------------------------------------------------- */
} // namespace llvm
ConvertUTF_RESTORE_WARNINGS
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