/*
* Copyright (C) 2012, 2013
* Wolfgang Bumiller
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is furnished to do
* so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "gmqcc.h"
static unsigned char utf8_lengths[256] = {
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* ascii characters */
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,
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,
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,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x80 - 0xBF are within multibyte sequences */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* they could be interpreted as 2-byte starts but */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* the codepoint would be < 127 */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* */
0, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* C0 and C1 would also result in overlong encodings */
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* */
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
/* with F5 the codepoint is above 0x10FFFF,
* F8-FB would start 5-byte sequences
* FC-FD would start 6-byte sequences
* ...
*/
};
static uchar_t utf8_range[5] = {
1, /* invalid - let's not allow the creation of 0-bytes :P */
1, /* ascii minimum */
0x80, /* 2-byte minimum */
0x800, /* 3-byte minimum */
0x10000, /* 4-byte minimum */
};
/** Analyze the next character and return various information if requested.
* @param _s An utf-8 string.
* @param _start Filled with the start byte-offset of the next valid character
* @param _len Filled with the length of the next valid character
* @param _ch Filled with the unicode value of the next character
* @param _maxlen Maximum number of bytes to read from _s
* @return Whether or not another valid character is in the string
*/
bool u8_analyze(const char *_s, size_t *_start, size_t *_len, uchar_t *_ch, size_t _maxlen)
{
const unsigned char *s = (const unsigned char*)_s;
size_t i, j;
size_t bits = 0;
uchar_t ch;
i = 0;
/* findchar: */
while (i < _maxlen && s[i] && (bits = utf8_lengths[s[i]]) == 0)
++i;
if (i >= _maxlen || !s[i]) {
if (_start) *_start = i;
if (_len) *_len = 0;
return false;
}
if (bits == 1) { /* ascii */
if (_start) *_start = i;
if (_len) *_len = 1;
if (_ch) *_ch = (uchar_t)s[i];
return true;
}
ch = (s[i] & (0xFF >> bits));
for (j = 1; j < bits; ++j)
{
if ( (s[i+j] & 0xC0) != 0x80 )
{
i += j;
/* in gmqcc, invalid / overlong encodings are considered an error
* goto findchar;
*/
if (!s[i]) goto done;
return false;
}
ch = (ch << 6) | (s[i+j] & 0x3F);
}
if (ch < utf8_range[bits] || ch >= 0x10FFFF)
{
/* same: error
* i += bits;
* goto findchar;
*/
return false;
}
done:
if (_start)
*_start = i;
if (_len)
*_len = bits;
if (_ch)
*_ch = ch;
return true;
}
/* might come in handy */
size_t u8_strlen(const char *_s)
{
size_t st, ln;
size_t len = 0;
const unsigned char *s = (const unsigned char*)_s;
while (*s)
{
/* ascii char, skip u8_analyze */
if (*s < 0x80)
{
++len;
++s;
continue;
}
/* invalid, skip u8_analyze */
if (*s < 0xC2)
{
++s;
continue;
}
if (!u8_analyze((const char*)s, &st, &ln, NULL, 0x10))
break;
/* valid character, skip after it */
s += st + ln;
++len;
}
return len;
}
size_t u8_strnlen(const char *_s, size_t n)
{
size_t st, ln;
size_t len = 0;
const unsigned char *s = (const unsigned char*)_s;
while (*s && n)
{
/* ascii char, skip u8_analyze */
if (*s < 0x80)
{
++len;
++s;
--n;
continue;
}
/* invalid, skip u8_analyze */
if (*s < 0xC2)
{
++s;
--n;
continue;
}
if (!u8_analyze((const char*)s, &st, &ln, NULL, n))
break;
/* valid character, see if it's still inside the range specified by n: */
if (n < st + ln)
return len;
++len;
n -= st + ln;
s += st + ln;
}
return len;
}
/* Required for character constants */
uchar_t u8_getchar(const char *_s, const char **_end)
{
size_t st, ln;
uchar_t ch;
if (!u8_analyze(_s, &st, &ln, &ch, 0x10))
ch = 0;
if (_end)
*_end = _s + st + ln;
return ch;
}
uchar_t u8_getnchar(const char *_s, const char **_end, size_t _maxlen)
{
size_t st, ln;
uchar_t ch;
if (!u8_analyze(_s, &st, &ln, &ch, _maxlen))
ch = 0;
if (_end)
*_end = _s + st + ln;
return ch;
}
/* required for \x{asdf}-like string escape sequences */
int u8_fromchar(uchar_t w, char *to, size_t maxlen)
{
if (maxlen < 1)
return 0;
if (!w)
return 0;
/* We may want an -f flag for this behaviour...
if (w >= 0xE000)
w -= 0xE000;
*/
if (w < 0x80)
{
to[0] = (char)w;
if (maxlen < 2)
return -1;
to[1] = 0;
return 1;
}
/* for a little speedup */
if (w < 0x800)
{
if (maxlen < 3)
{
to[0] = 0;
return -1;
}
to[2] = 0;
to[1] = 0x80 | (w & 0x3F); w >>= 6;
to[0] = 0xC0 | w;
return 2;
}
if (w < 0x10000)
{
if (maxlen < 4)
{
to[0] = 0;
return -1;
}
to[3] = 0;
to[2] = 0x80 | (w & 0x3F); w >>= 6;
to[1] = 0x80 | (w & 0x3F); w >>= 6;
to[0] = 0xE0 | w;
return 3;
}
/* RFC 3629 */
if (w <= 0x10FFFF)
{
if (maxlen < 5)
{
to[0] = 0;
return -1;
}
to[4] = 0;
to[3] = 0x80 | (w & 0x3F); w >>= 6;
to[2] = 0x80 | (w & 0x3F); w >>= 6;
to[1] = 0x80 | (w & 0x3F); w >>= 6;
to[0] = 0xF0 | w;
return 4;
}
return 0;
}