rockbox/firmware/common/unicode.c
Nils Wallménius 0b302f0cb9 Little bit of const correctness
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@23343 a1c6a512-1295-4272-9138-f99709370657
2009-10-25 10:42:21 +00:00

394 lines
10 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (c) 2004,2005 by Marcoen Hirschberg
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
/* Some conversion functions for handling UTF-8
*
* I got all the info from:
* http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
* and
* http://en.wikipedia.org/wiki/Unicode
*/
#include <stdio.h>
#include "file.h"
#include "debug.h"
#include "rbunicode.h"
#include "config.h"
#ifndef O_BINARY
#define O_BINARY 0
#endif
#define CODEPAGE_DIR ROCKBOX_DIR"/codepages"
static int default_codepage = 0;
static int loaded_cp_table = 0;
#ifdef HAVE_LCD_BITMAP
#define MAX_CP_TABLE_SIZE 32768
#define NUM_TABLES 5
static const char * const filename[NUM_TABLES] =
{
CODEPAGE_DIR"/iso.cp",
CODEPAGE_DIR"/932.cp", /* SJIS */
CODEPAGE_DIR"/936.cp", /* GB2312 */
CODEPAGE_DIR"/949.cp", /* KSX1001 */
CODEPAGE_DIR"/950.cp" /* BIG5 */
};
static const char cp_2_table[NUM_CODEPAGES] =
{
0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 0
};
static const char * const name_codepages[NUM_CODEPAGES+1] =
{
"ISO-8859-1",
"ISO-8859-7",
"ISO-8859-8",
"CP1251",
"ISO-8859-11",
"CP1256",
"ISO-8859-9",
"ISO-8859-2",
"CP1250",
"SJIS",
"GB-2312",
"KSX-1001",
"BIG5",
"UTF-8",
"unknown"
};
#else /* !HAVE_LCD_BITMAP, reduced support */
#define MAX_CP_TABLE_SIZE 640
#define NUM_TABLES 1
static const char * const filename[NUM_TABLES] = {
CODEPAGE_DIR"/isomini.cp"
};
static const char cp_2_table[NUM_CODEPAGES] =
{
0, 1, 1, 1, 1, 1, 0
};
static const char * const name_codepages[NUM_CODEPAGES+1] =
{
"ISO-8859-1",
"ISO-8859-7",
"CP1251",
"ISO-8859-9",
"ISO-8859-2",
"CP1250",
"UTF-8",
"unknown"
};
#endif
static unsigned short codepage_table[MAX_CP_TABLE_SIZE];
static const unsigned char utf8comp[6] =
{
0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC
};
/* Load codepage file into memory */
static int load_cp_table(int cp)
{
int i = 0;
int table = cp_2_table[cp];
int file, tablesize;
unsigned char tmp[2];
if (table == 0 || table == loaded_cp_table)
return 1;
file = open(filename[table-1], O_RDONLY|O_BINARY);
if (file < 0) {
DEBUGF("Can't open codepage file: %s.cp\n", filename[table-1]);
return 0;
}
tablesize = filesize(file) / 2;
if (tablesize > MAX_CP_TABLE_SIZE) {
DEBUGF("Invalid codepage file: %s.cp\n", filename[table-1]);
close(file);
return 0;
}
while (i < tablesize) {
if (!read(file, tmp, 2)) {
DEBUGF("Can't read from codepage file: %s.cp\n",
filename[table-1]);
loaded_cp_table = 0;
return 0;
}
codepage_table[i++] = (tmp[1] << 8) | tmp[0];
}
loaded_cp_table = table;
close(file);
return 1;
}
/* Encode a UCS value as UTF-8 and return a pointer after this UTF-8 char. */
unsigned char* utf8encode(unsigned long ucs, unsigned char *utf8)
{
int tail = 0;
if (ucs > 0x7F)
while (ucs >> (5*tail + 6))
tail++;
*utf8++ = (ucs >> (6*tail)) | utf8comp[tail];
while (tail--)
*utf8++ = ((ucs >> (6*tail)) & (MASK ^ 0xFF)) | COMP;
return utf8;
}
/* Recode an iso encoded string to UTF-8 */
unsigned char* iso_decode(const unsigned char *iso, unsigned char *utf8,
int cp, int count)
{
unsigned short ucs, tmp;
if (cp == -1) /* use default codepage */
cp = default_codepage;
if (!load_cp_table(cp)) cp = 0;
while (count--) {
if (*iso < 128 || cp == UTF_8) /* Already UTF-8 */
*utf8++ = *iso++;
else {
/* cp tells us which codepage to convert from */
switch (cp) {
case ISO_8859_7: /* Greek */
case WIN_1251: /* Cyrillic */
case ISO_8859_9: /* Turkish */
case ISO_8859_2: /* Latin Extended */
case WIN_1250: /* Central European */
#ifdef HAVE_LCD_BITMAP
case ISO_8859_8: /* Hebrew */
case ISO_8859_11: /* Thai */
case WIN_1256: /* Arabic */
#endif
tmp = ((cp-1)*128) + (*iso++ - 128);
ucs = codepage_table[tmp];
break;
#ifdef HAVE_LCD_BITMAP
case SJIS: /* Japanese */
if (*iso > 0xA0 && *iso < 0xE0) {
tmp = *iso++ | (0xA100 - 0x8000);
ucs = codepage_table[tmp];
break;
}
case GB_2312: /* Simplified Chinese */
case KSX_1001: /* Korean */
case BIG_5: /* Traditional Chinese */
if (count < 1 || !iso[1]) {
ucs = *iso++;
break;
}
/* we assume all cjk strings are written
in big endian order */
tmp = *iso++ << 8;
tmp |= *iso++;
tmp -= 0x8000;
ucs = codepage_table[tmp];
count--;
break;
#endif /* HAVE_LCD_BITMAP */
default:
ucs = *iso++;
break;
}
if (ucs == 0) /* unknown char, use replacement char */
ucs = 0xfffd;
utf8 = utf8encode(ucs, utf8);
}
}
return utf8;
}
/* Recode a UTF-16 string with little-endian byte ordering to UTF-8 */
unsigned char* utf16LEdecode(const unsigned char *utf16, unsigned char *utf8,
int count)
{
unsigned long ucs;
while (count > 0) {
/* Check for a surrogate pair */
if (utf16[1] >= 0xD8 && utf16[1] < 0xE0) {
ucs = 0x10000 + ((utf16[0] << 10) | ((utf16[1] - 0xD8) << 18)
| utf16[2] | ((utf16[3] - 0xDC) << 8));
utf16 += 4;
count -= 2;
} else {
ucs = (utf16[0] | (utf16[1] << 8));
utf16 += 2;
count -= 1;
}
utf8 = utf8encode(ucs, utf8);
}
return utf8;
}
/* Recode a UTF-16 string with big-endian byte ordering to UTF-8 */
unsigned char* utf16BEdecode(const unsigned char *utf16, unsigned char *utf8,
int count)
{
unsigned long ucs;
while (count > 0) {
if (*utf16 >= 0xD8 && *utf16 < 0xE0) { /* Check for a surrogate pair */
ucs = 0x10000 + (((utf16[0] - 0xD8) << 18) | (utf16[1] << 10)
| ((utf16[2] - 0xDC) << 8) | utf16[3]);
utf16 += 4;
count -= 2;
} else {
ucs = (utf16[0] << 8) | utf16[1];
utf16 += 2;
count -= 1;
}
utf8 = utf8encode(ucs, utf8);
}
return utf8;
}
#if 0 /* currently unused */
/* Recode any UTF-16 string to UTF-8 */
unsigned char* utf16decode(const unsigned char *utf16, unsigned char *utf8,
unsigned int count)
{
unsigned long ucs;
ucs = *(utf16++) << 8;
ucs |= *(utf16++);
if (ucs == 0xFEFF) /* Check for BOM */
return utf16BEdecode(utf16, utf8, count-1);
else if (ucs == 0xFFFE)
return utf16LEdecode(utf16, utf8, count-1);
else { /* ADDME: Should default be LE or BE? */
utf16 -= 2;
return utf16BEdecode(utf16, utf8, count);
}
}
#endif
/* Return the number of UTF-8 chars in a string */
unsigned long utf8length(const unsigned char *utf8)
{
unsigned long l = 0;
while (*utf8 != 0)
if ((*utf8++ & MASK) != COMP)
l++;
return l;
}
/* Decode 1 UTF-8 char and return a pointer to the next char. */
const unsigned char* utf8decode(const unsigned char *utf8, unsigned short *ucs)
{
unsigned char c = *utf8++;
unsigned long code;
int tail = 0;
if ((c <= 0x7f) || (c >= 0xc2)) {
/* Start of new character. */
if (c < 0x80) { /* U-00000000 - U-0000007F, 1 byte */
code = c;
} else if (c < 0xe0) { /* U-00000080 - U-000007FF, 2 bytes */
tail = 1;
code = c & 0x1f;
} else if (c < 0xf0) { /* U-00000800 - U-0000FFFF, 3 bytes */
tail = 2;
code = c & 0x0f;
} else if (c < 0xf5) { /* U-00010000 - U-001FFFFF, 4 bytes */
tail = 3;
code = c & 0x07;
} else {
/* Invalid size. */
code = 0xfffd;
}
while (tail-- && ((c = *utf8++) != 0)) {
if ((c & 0xc0) == 0x80) {
/* Valid continuation character. */
code = (code << 6) | (c & 0x3f);
} else {
/* Invalid continuation char */
code = 0xfffd;
utf8--;
break;
}
}
} else {
/* Invalid UTF-8 char */
code = 0xfffd;
}
/* currently we don't support chars above U-FFFF */
*ucs = (code < 0x10000) ? code : 0xfffd;
return utf8;
}
void set_codepage(int cp)
{
default_codepage = cp;
return;
}
/* seek to a given char in a utf8 string and
return its start position in the string */
int utf8seek(const unsigned char* utf8, int offset)
{
int pos = 0;
while (offset--) {
pos++;
while ((utf8[pos] & MASK) == COMP)
pos++;
}
return pos;
}
const char* get_codepage_name(int cp)
{
if (cp < 0 || cp>= NUM_CODEPAGES)
return name_codepages[NUM_CODEPAGES];
return name_codepages[cp];
}