sbase/libutf/rune.c

149 lines
4.1 KiB
C

/* MIT/X Consortium Copyright (c) 2012 Connor Lane Smith <cls@lubutu.com>
*
* 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 "../utf.h"
#define MIN(x,y) ((x) < (y) ? (x) : (y))
#define UTFSEQ(x) ((((x) & 0x80) == 0x00) ? 1 /* 0xxxxxxx */ \
: (((x) & 0xC0) == 0x80) ? 0 /* 10xxxxxx */ \
: (((x) & 0xE0) == 0xC0) ? 2 /* 110xxxxx */ \
: (((x) & 0xF0) == 0xE0) ? 3 /* 1110xxxx */ \
: (((x) & 0xF8) == 0xF0) ? 4 /* 11110xxx */ \
: (((x) & 0xFC) == 0xF8) ? 5 /* 111110xx */ \
: (((x) & 0xFE) == 0xFC) ? 6 /* 1111110x */ \
: 0 )
#define BADRUNE(x) ((x) < 0 || (x) > Runemax \
|| ((x) & 0xFFFE) == 0xFFFE \
|| ((x) >= 0xD800 && (x) <= 0xDFFF) \
|| ((x) >= 0xFDD0 && (x) <= 0xFDEF))
int
runetochar(char *s, const Rune *p)
{
Rune r = *p;
switch(runelen(r)) {
case 1: /* 0aaaaaaa */
s[0] = r;
return 1;
case 2: /* 00000aaa aabbbbbb */
s[0] = 0xC0 | ((r & 0x0007C0) >> 6); /* 110aaaaa */
s[1] = 0x80 | (r & 0x00003F); /* 10bbbbbb */
return 2;
case 3: /* aaaabbbb bbcccccc */
s[0] = 0xE0 | ((r & 0x00F000) >> 12); /* 1110aaaa */
s[1] = 0x80 | ((r & 0x000FC0) >> 6); /* 10bbbbbb */
s[2] = 0x80 | (r & 0x00003F); /* 10cccccc */
return 3;
case 4: /* 000aaabb bbbbcccc ccdddddd */
s[0] = 0xF0 | ((r & 0x1C0000) >> 18); /* 11110aaa */
s[1] = 0x80 | ((r & 0x03F000) >> 12); /* 10bbbbbb */
s[2] = 0x80 | ((r & 0x000FC0) >> 6); /* 10cccccc */
s[3] = 0x80 | (r & 0x00003F); /* 10dddddd */
return 4;
default:
return 0; /* error */
}
}
int
chartorune(Rune *p, const char *s)
{
return charntorune(p, s, UTFmax);
}
int
charntorune(Rune *p, const char *s, size_t len)
{
unsigned int i, n;
Rune r;
if(len == 0) /* can't even look at s[0] */
return 0;
switch((n = UTFSEQ(s[0]))) {
case 1: r = s[0]; break; /* 0xxxxxxx */
case 2: r = s[0] & 0x1F; break; /* 110xxxxx */
case 3: r = s[0] & 0x0F; break; /* 1110xxxx */
case 4: r = s[0] & 0x07; break; /* 11110xxx */
case 5: r = s[0] & 0x03; break; /* 111110xx */
case 6: r = s[0] & 0x01; break; /* 1111110x */
default: /* invalid sequence */
*p = Runeerror;
return 1;
}
/* add values from continuation bytes */
for(i = 1; i < MIN(n, len); i++)
if((s[i] & 0xC0) == 0x80) {
/* add bits from continuation byte to rune value
* cannot overflow: 6 byte sequences contain 31 bits */
r = (r << 6) | (s[i] & 0x3F); /* 10xxxxxx */
}
else { /* expected continuation */
*p = Runeerror;
return i;
}
if(i < n) /* must have reached len limit */
return 0;
/* reject invalid or overlong sequences */
if(BADRUNE(r) || runelen(r) < (int)n)
r = Runeerror;
*p = r;
return n;
}
int
runelen(Rune r)
{
if(BADRUNE(r))
return 0; /* error */
else if(r <= 0x7F)
return 1;
else if(r <= 0x07FF)
return 2;
else if(r <= 0xFFFF)
return 3;
else
return 4;
}
size_t
runenlen(const Rune *p, size_t len)
{
size_t i, n = 0;
for(i = 0; i < len; i++)
n += runelen(p[i]);
return n;
}
int
fullrune(const char *s, size_t len)
{
Rune r;
return charntorune(&r, s, len) > 0;
}