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// Copyright (C) 2003 Mooffie <mooffie@typo.co.il>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
#include <config.h>
#include "utf8.h"
#include "univalues.h"
#include "dbg.h"
// utf8_to_unicode() - converts a UTF-8 string to unichars. When an
// incomplete sequence is encountered, *problem will point to its head (it's
// similar to what iconv does).
//
// This function converts UTF-8 to UCS-4 (not to UTF-32) -- that's why it
// recognizes 5- and 6-byte sequences.
int utf8_to_unicode(unichar *dest, const char *s, int len, const char **problem)
{
int length = 0;
const char *end = s + len;
if (problem)
*problem = NULL;
// constant expressions are evaluated at compile time, of course.
#define FRST(t) ((*s & ((1 << (8-t-1)) - 1)) << (t-1)*6)
#define UC(t,n) (*(s+n-1) & 0x3F) << ((t-n)*6)
while (s < end) {
if (!(*s & 0x80)) {
*dest++ = *s;
s++;
} else if ((*s & 0xE0) == 0xC0) {
if ((end - s) >= 2) {
*dest++ = FRST(2) | UC(2,2);
s += 2;
} else {
if (problem)
*problem = s;
break;
}
} else if ((*s & 0xF0) == 0xE0) {
if ((end - s) >= 3) {
*dest++ = FRST(3) | UC(3,2) | UC(3,3);
s += 3;
} else {
if (problem)
*problem = s;
break;
}
} else if ((*s & 0xF8) == 0xF0) {
if ((end - s) >= 4) {
*dest++ = FRST(4) | UC(4,2) | UC(4,3) | UC(4,4);
s += 4;
} else {
if (problem)
*problem = s;
break;
}
} else if ((*s & 0xFC) == 0xF8) {
if ((end - s) >= 5) {
*dest++ = FRST(5) | UC(5,2) | UC(5,3) | UC(5,4) | UC(5,5);
s += 5;
} else {
if (problem)
*problem = s;
break;
}
} else if ((*s & 0xFE) == 0xFC) {
if ((end - s) >= 6) {
*dest++ = FRST(6) | UC(6,2) | UC(6,3) | UC(6,4) | UC(6,5) | UC(6,6);
s += 6;
} else {
if (problem)
*problem = s;
break;
}
} else {
*dest++ = UNI_REPLACEMENT;
s++;
}
length++;
}
return length;
#undef FRST
#undef UC
}
// unicode_to_utf8() - converts unichars to UTF-8.
int unicode_to_utf8(char *dest, const unichar *us, int len)
{
#define UC(n) ((*us >> 6*n) & 0x3F)
#define CNT(n) (((1 << n) - 1) << (8 - n))
int nbytes = 0;
while (len--) {
if (*us < 0x80) {
*dest++ = *us;
nbytes += 1;
} else if (*us < 0x800) {
*dest++ = UC(1) | CNT(2);
*dest++ = UC(0) | 0x80;
nbytes += 2;
} else if (*us < 0x10000) {
*dest++ = UC(2) | CNT(3);
*dest++ = UC(1) | 0x80;
*dest++ = UC(0) | 0x80;
nbytes += 3;
} else if (*us < 0x200000) {
*dest++ = UC(3) | CNT(4);
*dest++ = UC(2) | 0x80;
*dest++ = UC(1) | 0x80;
*dest++ = UC(0) | 0x80;
nbytes += 4;
} else if (*us < 0x4000000) {
*dest++ = UC(4) | CNT(5);
*dest++ = UC(3) | 0x80;
*dest++ = UC(2) | 0x80;
*dest++ = UC(1) | 0x80;
*dest++ = UC(0) | 0x80;
nbytes += 5;
} else {
*dest++ = UC(5) | CNT(6);
*dest++ = UC(4) | 0x80;
*dest++ = UC(3) | 0x80;
*dest++ = UC(2) | 0x80;
*dest++ = UC(1) | 0x80;
*dest++ = UC(0) | 0x80;
nbytes += 6;
}
us++;
}
return nbytes;
#undef UC
#undef CNT
}
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