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/*
* 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 TSK_UNI_MAX_LEGAL_UTF32 in UTF-32 conversions.
See the header file "ConvertUTF.h" for complete documentation.
------------------------------------------------------------------------ */
/** \file tsk_unicode.c
* A local copy of the Unicode conversion routines from unicode.org.
*/
#include "tsk_base_i.h"
/* Some fundamental constants */
typedef unsigned long UTF32; /* at least 32 bits */
#define TSK_UNI_REPLACEMENT_CHAR (UTF32)0x0000FFFD
#define TSK_UNI_MAX_BMP (UTF32)0x0000FFFF
#define TSK_UNI_MAX_UTF16 (UTF32)0x0010FFFF
#define TSK_UNI_MAX_UTF32 (UTF32)0x7FFFFFFF
#define TSK_UNI_MAX_LEGAL_UTF32 (UTF32)0x0010FFFF
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
#define false 0
#define true 1
/* --------------------------------------------------------------------- */
/* --------------------------------------------------------------------- */
/*
* 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.
*/
/* --------------------------------------------------------------------- */
/**
* \ingroup baselib
* Convert a UTF-16 string to UTF-8.
* @param endian Endian ordering flag of UTF-16 text
* @param sourceStart Pointer to pointer to start of UTF-16 string. Will be updated to last char proccessed.
* @param sourceEnd Pointer to one entry past end of UTF-16 string
* @param targetStart Pointer to pointer to place where UTF-8 string should be written. Will be updated to next place to write to.
* @param targetEnd Pointer to end of UTF-8 buffer
* @param flags Flags used during conversion
* @returns error code
*/
TSKConversionResult
tsk_UTF16toUTF8(TSK_ENDIAN_ENUM endian, const UTF16 ** sourceStart,
const UTF16 * sourceEnd, UTF8 ** targetStart,
UTF8 * targetEnd, TSKConversionFlags flags)
{
TSKConversionResult result = TSKconversionOK;
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 = tsk_getu16(endian, (uint8_t *) source);
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 = tsk_getu16(endian, (uint8_t *) source);
++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;
}
else if (flags == TSKstrictConversion) { /* it's an unpaired high surrogate */
result = TSKsourceIllegal;
break;
}
// replace with another character
else {
ch = '^';
}
}
else { /* We don't have the 16 bits following the high surrogate. */
--source; /* return to the high surrogate */
result = TSKsourceExhausted;
break;
}
}
/* UTF-16 surrogate values are illegal in UTF-32 */
else if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
if (flags == TSKstrictConversion) {
--source; /* return to the illegal value itself */
result = TSKsourceIllegal;
break;
}
// replace with another character
else {
ch = '^';
}
}
/* 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 = TSK_UNI_REPLACEMENT_CHAR;
}
target += bytesToWrite;
if (target > targetEnd) {
source = oldSource; /* Back up source pointer! */
target -= bytesToWrite;
result = TSKtargetExhausted;
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;
}
/**
* \ingroup baselib
* Convert a UTF-16 string in local endian ordering to UTF-8.
* @param sourceStart Pointer to pointer to start of UTF-16 string. Will be updated to last char proccessed.
* @param sourceEnd Pointer to one entry past end of UTF-16 string
* @param targetStart Pointer to pointer to place where UTF-8 string should be written. Will be updated to next place to write to.
* @param targetEnd Pointer to end of UTF-8 buffer
* @param flags Flags used during conversion
* @returns error code
*/
TSKConversionResult
tsk_UTF16toUTF8_lclorder(const UTF16 ** sourceStart,
const UTF16 * sourceEnd, UTF8 ** targetStart,
UTF8 * targetEnd, TSKConversionFlags flags)
{
TSKConversionResult result = TSKconversionOK;
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;
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;
}
else if (flags == TSKstrictConversion) { /* it's an unpaired high surrogate */
result = TSKsourceIllegal;
break;
}
// replace with another character
else {
ch = '^';
}
}
else { /* We don't have the 16 bits following the high surrogate. */
--source; /* return to the high surrogate */
result = TSKsourceExhausted;
break;
}
}
/* UTF-16 surrogate values are illegal in UTF-32 */
else if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
if (flags == TSKstrictConversion) {
--source; /* return to the illegal value itself */
result = TSKsourceIllegal;
break;
}
// replace with another character
else {
ch = '^';
}
}
/* 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 = TSK_UNI_REPLACEMENT_CHAR;
}
target += bytesToWrite;
if (target > targetEnd) {
source = oldSource; /* Back up source pointer! */
target -= bytesToWrite;
result = TSKtargetExhausted;
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)) > 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
tsk_isLegalUTF8Sequence(const UTF8 * source, const UTF8 * sourceEnd)
{
int length = trailingBytesForUTF8[*source] + 1;
if (source + length > sourceEnd) {
return false;
}
return isLegalUTF8(source, length);
}
/**
* Cleans up the passed in string to replace invalid
* UTF-8 values with the passed in character.
* @param source String to be cleaned up
* @param replacement Character to insert into source as needed.
*/
void
tsk_cleanupUTF8(char * source, const char replacement)
{
size_t total_len = strlen(source);
size_t cur_idx = 0;
while (cur_idx < total_len) {
int length = trailingBytesForUTF8[(UTF8)source[cur_idx]] + 1;
if (cur_idx + length > total_len) {
while (cur_idx < total_len) {
source[cur_idx] = replacement;
cur_idx++;
}
break;
}
if (isLegalUTF8((UTF8 *)&source[cur_idx], length) == false) {
int i;
for (i = 0; i < length; i++) {
source[cur_idx + i] = replacement;
}
}
cur_idx += length;
}
}
/* --------------------------------------------------------------------- */
/**
* \ingroup baselib
* Convert a UTF-8 string to UTF-16 (in local endian ordering).
* @param sourceStart Pointer to pointer to start of UTF-8 string. Will be updated to last char proccessed.
* @param sourceEnd Pointer to one entry past end of UTF-8 string
* @param targetStart Pointer to pointer to place where UTF-16 string should be written. Will be updated to next place to write to.
* @param targetEnd Pointer to end of UTF-16 buffer
* @param flags Flags used during conversion
* @returns error code
*/
TSKConversionResult
tsk_UTF8toUTF16(const UTF8 ** sourceStart,
const UTF8 * sourceEnd, UTF16 ** targetStart,
UTF16 * targetEnd, TSKConversionFlags flags)
{
TSKConversionResult result = TSKconversionOK;
const UTF8 *source = *sourceStart;
UTF16 *target = *targetStart;
while (source < sourceEnd) {
UTF32 ch = 0;
unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
if (source + extraBytesToRead >= sourceEnd) {
result = TSKsourceExhausted;
break;
}
/* Do this check whether lenient or strict */
if (!isLegalUTF8(source, extraBytesToRead + 1)) {
result = TSKsourceIllegal;
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 = TSKtargetExhausted;
break;
}
if (ch <= TSK_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 == TSKstrictConversion) {
source -= (extraBytesToRead + 1); /* return to the illegal value itself */
result = TSKsourceIllegal;
break;
}
else {
*target++ = TSK_UNI_REPLACEMENT_CHAR;
}
}
else {
*target++ = (UTF16) ch; /* normal case */
}
}
else if (ch > TSK_UNI_MAX_UTF16) {
if (flags == TSKstrictConversion) {
result = TSKsourceIllegal;
source -= (extraBytesToRead + 1); /* return to the start */
break; /* Bail out; shouldn't continue */
}
else {
*target++ = TSK_UNI_REPLACEMENT_CHAR;
}
}
else {
/* target is a character in range 0xFFFF - 0x10FFFF. */
if (target + 1 >= targetEnd) {
source -= (extraBytesToRead + 1); /* Back up source pointer! */
result = TSKtargetExhausted;
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;
}
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