/* ================================================================ */
/*
File: ConvertUTF.C
Author: Mark E. Davis
* Copyright 1994-1999 IBM Corp.. All rights reserved.
*
* IBM Corp. grants the user a nonexclusive right and license to use, execute,
* display, modify, and prepare and/or have prepared derivative works of the
* code, including but not limited to creating software products which
* incorporate the code or derivative works thereof.
*
* IBM Corp. grants the user a right and license to reproduce and distribute
* the code as long as this entire copyright notice is reproduced in the code
* or reproduction.
*
* The code is provided AS-IS, and IBM Corp. disclaims all warranties,
* either express or implied, including, but not limited to implied
* warranties of merchantability and fitness for a particular purpose.
* In no event will IBM Corp. be liable for any damages whatsoever (including,
* without limitation, damages for loss of business profits, business
* interruption, loss of business information, or other pecuniary
* loss) arising out of the use or inability to use this code, even
* if IBM Corp. has been advised of the possibility of such damages.
* Because some states do not allow the exclusion or limitation of
* liability for consequential or incidental damages, the above
* limitation may not apply to you.
*/
/* ================================================================ */
#include "CVTUTF.H"
/* ================================================================ */
const UCS4 kReplacementCharacter = 0x0000FFFDUL;
const UCS4 kMaximumUCS2 = 0x0000FFFFUL;
const UCS4 kMaximumUTF16 = 0x0010FFFFUL;
const UCS4 kMaximumUCS4 = 0x7FFFFFFFUL;
const int halfShift = 10;
const UCS4 halfBase = 0x0010000UL;
const UCS4 halfMask = 0x3FFUL;
const UCS4 kSurrogateHighStart = 0xD800UL;
const UCS4 kSurrogateHighEnd = 0xDBFFUL;
const UCS4 kSurrogateLowStart = 0xDC00UL;
const UCS4 kSurrogateLowEnd = 0xDFFFUL;
/* ================================================================ */
ConversionResult ConvertUCS4toUTF16 (
UCS4** sourceStart, const UCS4* sourceEnd,
UTF16** targetStart, const UTF16* targetEnd) {
ConversionResult result = ok;
register UCS4* source = *sourceStart;
register UTF16* target = *targetStart;
while (source < sourceEnd) {
register UCS4 ch;
if (target >= targetEnd) {
result = targetExhausted; break;
};
ch = *source++;
if (ch <= kMaximumUCS2) {
*target++ = ch;
} else if (ch > kMaximumUTF16) {
*target++ = kReplacementCharacter;
} else {
if (target + 1 >= targetEnd) {
result = targetExhausted; break;
};
ch -= halfBase;
*target++ = (ch >> halfShift) + kSurrogateHighStart;
*target++ = (ch & halfMask) + kSurrogateLowStart;
};
};
*sourceStart = source;
*targetStart = target;
return result;
};
/* ================================================================ */
ConversionResult ConvertUTF16toUCS4 (
UTF16** sourceStart, UTF16* sourceEnd,
UCS4** targetStart, const UCS4* targetEnd) {
ConversionResult result = ok;
register UTF16* source = *sourceStart;
register UCS4* target = *targetStart;
while (source < sourceEnd) {
register UCS4 ch;
ch = *source++;
if (ch >= kSurrogateHighStart && ch <= kSurrogateHighEnd && source < sourceEnd) {
register UCS4 ch2 = *source;
if (ch2 >= kSurrogateLowStart && ch2 <= kSurrogateLowEnd) {
ch = ((ch - kSurrogateHighStart) << halfShift)
+ (ch2 - kSurrogateLowStart) + halfBase;
++source;
};
};
if (target >= targetEnd) {
result = targetExhausted; break;
};
*target++ = ch;
};
*sourceStart = source;
*targetStart = target;
return result;
};
/* ================================================================ */
UCS4 offsetsFromUTF8[6] = {0x00000000UL, 0x00003080UL, 0x000E2080UL,
0x03C82080UL, 0xFA082080UL, 0x82082080UL};
char bytesFromUTF8[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};
UTF8 firstByteMark[7] = {0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC};
/* ================================================================ */
/* This code is similar in effect to making successive calls on the
mbtowc and wctomb routines in FSS-UTF. However, it is considerably
different in code:
* it is adapted to be consistent with UTF16,
* 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 switch statements.
*/
/* ================================================================ */
ConversionResult ConvertUTF16toUTF8 (
UTF16** sourceStart, const UTF16* sourceEnd,
UTF8** targetStart, const UTF8* targetEnd)
{
ConversionResult result = ok;
register UTF16* source = *sourceStart;
register UTF8* target = *targetStart;
while (source < sourceEnd) {
register UCS4 ch;
register unsigned short bytesToWrite = 0;
register const UCS4 byteMask = 0xBF;
register const UCS4 byteMark = 0x80;
ch = *source++;
if (ch >= kSurrogateHighStart && ch <= kSurrogateHighEnd
&& source < sourceEnd) {
register UCS4 ch2 = *source;
if (ch2 >= kSurrogateLowStart && ch2 <= kSurrogateLowEnd) {
ch = ((ch - kSurrogateHighStart) << halfShift)
+ (ch2 - kSurrogateLowStart) + halfBase;
++source;
};
};
if (ch < 0x80) { bytesToWrite = 1;
} else if (ch < 0x800) { bytesToWrite = 2;
} else if (ch < 0x10000) { bytesToWrite = 3;
} else if (ch < 0x200000) { bytesToWrite = 4;
} else if (ch < 0x4000000) { bytesToWrite = 5;
} else if (ch <= kMaximumUCS4){ bytesToWrite = 6;
} else { bytesToWrite = 2;
ch = kReplacementCharacter;
}; /* I wish there were a smart way to avoid this conditional */
target += bytesToWrite;
if (target > targetEnd) {
target -= bytesToWrite; result = targetExhausted; break;
};
switch (bytesToWrite) { /* note: code falls through cases! */
case 6: *--target = (ch | byteMark) & byteMask; ch >>= 6;
case 5: *--target = (ch | byteMark) & byteMask; ch >>= 6;
case 4: *--target = (ch | byteMark) & byteMask; ch >>= 6;
case 3: *--target = (ch | byteMark) & byteMask; ch >>= 6;
case 2: *--target = (ch | byteMark) & byteMask; ch >>= 6;
case 1: *--target = ch | firstByteMark[bytesToWrite];
};
target += bytesToWrite;
};
*sourceStart = source;
*targetStart = target;
return result;
};
/* ================================================================ */
ConversionResult ConvertUTF8toUTF16 (
UTF8** sourceStart, UTF8* sourceEnd,
UTF16** targetStart, const UTF16* targetEnd)
{
ConversionResult result = ok;
register UTF8* source = *sourceStart;
register UTF16* target = *targetStart;
while (source < sourceEnd) {
register UCS4 ch = 0;
register unsigned short extraBytesToWrite = bytesFromUTF8[*source];
if (source + extraBytesToWrite > sourceEnd) {
result = sourceExhausted; break;
};
switch(extraBytesToWrite) { /* note: code falls through cases! */
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[extraBytesToWrite];
if (target >= targetEnd) {
result = targetExhausted; break;
};
if (ch <= kMaximumUCS2) {
*target++ = ch;
} else if (ch > kMaximumUTF16) {
*target++ = kReplacementCharacter;
} else {
if (target + 1 >= targetEnd) {
result = targetExhausted; break;
};
ch -= halfBase;
*target++ = (ch >> halfShift) + kSurrogateHighStart;
*target++ = (ch & halfMask) + kSurrogateLowStart;
};
};
*sourceStart = source;
*targetStart = target;
return result;
};
/* ================================================================ */
ConversionResult ConvertUCS4toUTF8 (
UCS4** sourceStart, const UCS4* sourceEnd,
UTF8** targetStart, const UTF8* targetEnd)
{
ConversionResult result = ok;
register UCS4* source = *sourceStart;
register UTF8* target = *targetStart;
while (source < sourceEnd) {
register UCS4 ch;
register unsigned short bytesToWrite = 0;
register const UCS4 byteMask = 0xBF;
register const UCS4 byteMark = 0x80;
ch = *source++;
if (ch >= kSurrogateHighStart && ch <= kSurrogateHighEnd
&& source < sourceEnd) {
register UCS4 ch2 = *source;
if (ch2 >= kSurrogateLowStart && ch2 <= kSurrogateLowEnd) {
ch = ((ch - kSurrogateHighStart) << halfShift)
+ (ch2 - kSurrogateLowStart) + halfBase;
++source;
};
};
if (ch < 0x80) { bytesToWrite = 1;
} else if (ch < 0x800) { bytesToWrite = 2;
} else if (ch < 0x10000) { bytesToWrite = 3;
} else if (ch < 0x200000) { bytesToWrite = 4;
} else if (ch < 0x4000000) { bytesToWrite = 5;
} else if (ch <= kMaximumUCS4){ bytesToWrite = 6;
} else { bytesToWrite = 2;
ch = kReplacementCharacter;
}; /* I wish there were a smart way to avoid this conditional */
target += bytesToWrite;
if (target > targetEnd) {
target -= bytesToWrite; result = targetExhausted; break;
};
switch (bytesToWrite) { /* note: code falls through cases! */
case 6: *--target = (ch | byteMark) & byteMask; ch >>= 6;
case 5: *--target = (ch | byteMark) & byteMask; ch >>= 6;
case 4: *--target = (ch | byteMark) & byteMask; ch >>= 6;
case 3: *--target = (ch | byteMark) & byteMask; ch >>= 6;
case 2: *--target = (ch | byteMark) & byteMask; ch >>= 6;
case 1: *--target = ch | firstByteMark[bytesToWrite];
};
target += bytesToWrite;
};
*sourceStart = source;
*targetStart = target;
return result;
};
/* ================================================================ */
ConversionResult ConvertUTF8toUCS4 (
UTF8** sourceStart, UTF8* sourceEnd,
UCS4** targetStart, const UCS4* targetEnd)
{
ConversionResult result = ok;
register UTF8* source = *sourceStart;
register UCS4* target = *targetStart;
while (source < sourceEnd) {
register UCS4 ch = 0;
register unsigned short extraBytesToWrite = bytesFromUTF8[*source];
if (source + extraBytesToWrite > sourceEnd) {
result = sourceExhausted; break;
};
switch(extraBytesToWrite) { /* note: code falls through cases! */
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[extraBytesToWrite];
if (target >= targetEnd) {
result = targetExhausted; break;
};
if (ch <= kMaximumUCS2) {
*target++ = ch;
} else if (ch > kMaximumUCS4) {
*target++ = kReplacementCharacter;
} else {
if (target + 1 >= targetEnd) {
result = targetExhausted; break;
};
ch -= halfBase;
*target++ = (ch >> halfShift) + kSurrogateHighStart;
*target++ = (ch & halfMask) + kSurrogateLowStart;
};
};
*sourceStart = source;
*targetStart = target;
return result;
};
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