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+/* ================================================================ */
+/*
+File: ConvertUTF.C
+Author: Mark E. Davis
+Copyright (C) 1994 Taligent, Inc. All rights reserved.
+
+This code is copyrighted. Under the copyright laws, this code may not
+be copied, in whole or part, without prior written consent of Taligent.
+
+Taligent grants the right to use or reprint this code as long as this
+ENTIRE copyright notice is reproduced in the code or reproduction.
+The code is provided AS-IS, AND TALIGENT 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 TALIGENT 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 TALIGENT 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.
+
+RESTRICTED RIGHTS LEGEND: Use, duplication, or disclosure by the
+government is subject to restrictions as set forth in subparagraph
+(c)(l)(ii) of the Rights in Technical Data and Computer Software
+clause at DFARS 252.227-7013 and FAR 52.227-19.
+
+This code may be protected by one or more U.S. and International
+Patents.
+
+TRADEMARKS: Taligent and the Taligent Design Mark are registered
+trademarks of Taligent, Inc.
+*/
+/* ================================================================ */
+
+#include "CVTUTF.H"
+
+/* ================================================================ */
+
+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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