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Initial add.
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@icculus
icculus committed Nov 5, 2006
1 parent 49f0f53 commit 95cbc6b
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338 changes: 338 additions & 0 deletions physfs_unicode.c
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#if HAVE_CONFIG_H
# include <config.h>
#endif

#include "physfs.h"

#define __PHYSICSFS_INTERNAL__
#include "physfs_internal.h"


/*
* From rfc3629, the UTF-8 spec:
* http://www.ietf.org/rfc/rfc3629.txt
*
* Char. number range | UTF-8 octet sequence
* (hexadecimal) | (binary)
* --------------------+---------------------------------------------
* 0000 0000-0000 007F | 0xxxxxxx
* 0000 0080-0000 07FF | 110xxxxx 10xxxxxx
* 0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx
* 0001 0000-0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
*/


/*
* This may not be the best value, but it's one that isn't represented
* in Unicode (0x10FFFF is the largest codepoint value). We return this
* value from utf8codepoint() if there's bogus bits in the
* stream. utf8codepoint() will turn this value into something
* reasonable (like a question mark), for text that wants to try to recover,
* whereas utf8valid() will use the value to determine if a string has bad
* bits.
*/
#define UNICODE_BOGUS_CHAR_VALUE 0xFFFFFFFF

/*
* This is the codepoint we currently return when there was bogus bits in a
* UTF-8 string. May not fly in Asian locales?
*/
#define UNICODE_BOGUS_CHAR_CODEPOINT '?'

static PHYSFS_uint32 utf8codepoint(const char **_str)
{
const char *str = *_str;
PHYSFS_uint32 retval = 0;
PHYSFS_uint32 octet = (PHYSFS_uint32) ((PHYSFS_uint8) *str);
PHYSFS_uint32 octet2, octet3, octet4;

if (octet == 0) /* null terminator, end of string. */
return 0;

else if (octet < 128) /* one octet char: 0 to 127 */
{
(*_str)++; /* skip to next possible start of codepoint. */
return(octet);
} /* else if */

else if ((octet > 127) && (octet < 192)) /* bad (starts with 10xxxxxx). */
{
/*
* Apparently each of these is supposed to be flagged as a bogus
* char, instead of just resyncing to the next valid codepoint.
*/
(*_str)++; /* skip to next possible start of codepoint. */
return UNICODE_BOGUS_CHAR_VALUE;
} /* else if */

else if (octet < 224) /* two octets */
{
octet -= (128+64);
octet2 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet2 & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

*_str += 2; /* skip to next possible start of codepoint. */
retval = ((octet << 6) | (octet2 - 128));
if ((retval >= 0x80) && (retval <= 0x7FF))
return retval;
} /* else if */

else if (octet < 240) /* three octets */
{
octet -= (128+64+32);
octet2 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet2 & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

octet3 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet3 & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

*_str += 3; /* skip to next possible start of codepoint. */
retval = ( ((octet << 12)) | ((octet2-128) << 6) | ((octet3-128)) );

/* There are seven "UTF-16 surrogates" that are illegal in UTF-8. */
switch (retval)
{
case 0xD800:
case 0xDB7F:
case 0xDB80:
case 0xDBFF:
case 0xDC00:
case 0xDF80:
case 0xDFFF:
return UNICODE_BOGUS_CHAR_VALUE;
} /* switch */

/* 0xFFFE and 0xFFFF are illegal, too, so we check them at the edge. */
if ((retval >= 0x800) && (retval <= 0xFFFD))
return retval;
} /* else if */

else if (octet < 248) /* four octets */
{
octet -= (128+64+32+16);
octet2 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet2 & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

octet3 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet3 & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

octet4 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet4 & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

*_str += 4; /* skip to next possible start of codepoint. */
retval = ( ((octet << 18)) | ((octet2 - 128) << 12) |
((octet3 - 128) << 6) | ((octet4 - 128)) );
if ((retval >= 0x10000) && (retval <= 0x10FFFF))
return retval;
} /* else if */

/*
* Five and six octet sequences became illegal in rfc3629.
* We throw the codepoint away, but parse them to make sure we move
* ahead the right number of bytes and don't overflow the buffer.
*/

else if (octet < 252) /* five octets */
{
octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

*_str += 5; /* skip to next possible start of codepoint. */
return UNICODE_BOGUS_CHAR_VALUE;
} /* else if */

else /* six octets */
{
octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));
if ((octet & (128+64)) != 128) /* Format isn't 10xxxxxx? */
return UNICODE_BOGUS_CHAR_VALUE;

*_str += 6; /* skip to next possible start of codepoint. */
return UNICODE_BOGUS_CHAR_VALUE;
} /* else if */

return UNICODE_BOGUS_CHAR_VALUE;
} /* utf8codepoint */

void PHYSFS_utf8toucs4(const char *src, PHYSFS_uint32 *dst, PHYSFS_uint64 len)
{
len -= sizeof (PHYSFS_uint32); /* save room for null char. */
while (len >= sizeof (PHYSFS_uint32))
{
PHYSFS_uint32 cp = utf8codepoint(&src);
if (cp == 0)
break;
else if (cp == UNICODE_BOGUS_CHAR_VALUE)
cp = UNICODE_BOGUS_CHAR_CODEPOINT;
*(dst++) = cp;
len -= sizeof (PHYSFS_uint32);
} /* while */

*dst = 0;
} /* PHYSFS_utf8toucs4 */

void PHYSFS_utf8toucs2(const char *src, PHYSFS_uint16 *dst, PHYSFS_uint64 len)
{
len -= sizeof (PHYSFS_uint16); /* save room for null char. */
while (len >= sizeof (PHYSFS_uint16))
{
PHYSFS_uint32 cp = utf8codepoint(&src);
if (cp == 0)
break;
else if (cp == UNICODE_BOGUS_CHAR_VALUE)
cp = UNICODE_BOGUS_CHAR_CODEPOINT;

/* !!! BLUESKY: UTF-16 surrogates? */
if (cp > 0xFFFF)
cp = UNICODE_BOGUS_CHAR_CODEPOINT;

*(dst++) = cp;
len -= sizeof (PHYSFS_uint16);
} /* while */

*dst = 0;
} /* PHYSFS_utf8toucs2 */

static void utf8fromcodepoint(PHYSFS_uint32 cp, char **_dst, PHYSFS_uint64 *_len)
{
char *dst = *_dst;
PHYSFS_uint64 len = *_len;

if (len == 0)
return;

if (cp > 0x10FFFF)
cp = UNICODE_BOGUS_CHAR_CODEPOINT;
else if ((cp == 0xFFFE) || (cp == 0xFFFF)) /* illegal values. */
cp = UNICODE_BOGUS_CHAR_CODEPOINT;
else
{
/* There are seven "UTF-16 surrogates" that are illegal in UTF-8. */
switch (cp)
{
case 0xD800:
case 0xDB7F:
case 0xDB80:
case 0xDBFF:
case 0xDC00:
case 0xDF80:
case 0xDFFF:
cp = UNICODE_BOGUS_CHAR_CODEPOINT;
} /* switch */
} /* else */

/* Do the encoding... */
if (cp < 0x80)
{
*(dst++) = (char) cp;
len--;
} /* if */

else if (cp < 0x800)
{
if (len < 2)
len = 0;
else
{
*(dst++) = (char) ((cp >> 6) | 128 | 64);
*(dst++) = (char) (cp & 0x3F) | 128;
len -= 2;
} /* else */
} /* else if */

else if (cp < 0x10000)
{
if (len < 3)
len = 0;
else
{
*(dst++) = (char) ((cp >> 12) | 128 | 64 | 32);
*(dst++) = (char) ((cp >> 6) & 0x3F) | 128;
*(dst++) = (char) (cp & 0x3F) | 128;
len -= 3;
} /* else */
} /* else if */

else
{
if (len < 4)
len = 0;
else
{
*(dst++) = (char) ((cp >> 18) | 128 | 64 | 32 | 16);
*(dst++) = (char) ((cp >> 12) & 0x3F) | 128;
*(dst++) = (char) ((cp >> 6) & 0x3F) | 128;
*(dst++) = (char) (cp & 0x3F) | 128;
len -= 4;
} /* else if */
} /* else */

*_dst = dst;
*_len = len;
} /* utf8fromcodepoint */

#define UTF8FROMTYPE(typ, src, dst, len) \
len--; \
while (len) \
{ \
const PHYSFS_uint32 cp = (PHYSFS_uint32) *(src++); \
if (cp == 0) break; \
utf8fromcodepoint(cp, &dst, &len); \
} \
*dst = '\0'; \

void PHYSFS_utf8fromucs4(const PHYSFS_uint32 *src, char *dst, PHYSFS_uint64 len)
{
UTF8FROMTYPE(PHYSFS_uint32, src, dst, len);
} /* PHYSFS_utf8fromucs4 */

void PHYSFS_utf8fromucs2(const PHYSFS_uint16 *src, char *dst, PHYSFS_uint64 len)
{
UTF8FROMTYPE(PHYSFS_uint64, src, dst, len);
} /* PHYSFS_utf8fromucs4 */

/* latin1 maps to unicode codepoints directly, we just utf-8 encode it. */
void PHYSFS_utf8fromlatin1(const char *src, char *dst, PHYSFS_uint64 len)
{
UTF8FROMTYPE(PHYSFS_uint8, src, dst, len);
} /* PHYSFS_utf8fromlatin1 */

#undef UTF8FROMTYPE

/* end of physfs_unicode.c ... */

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