ref: a442a0418f06b673559c93a69e3167b4460d6d07
dir: /utf.c/
/*
* The authors of this software are Rob Pike and Ken Thompson.
* Copyright (c) 2002 by Lucent Technologies.
* Permission to use, copy, modify, and distribute this software for any
* purpose without fee is hereby granted, provided that this entire notice
* is included in all copies of any software which is or includes a copy
* or modification of this software and in all copies of the supporting
* documentation for such software.
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE
* ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
* OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
*/
#include <stdlib.h>
#include <string.h>
#include "utf.h"
#include "utfdata.h"
#define nelem(a) (int)(sizeof (a) / sizeof (a)[0])
typedef unsigned char uchar;
enum
{
Bit1 = 7,
Bitx = 6,
Bit2 = 5,
Bit3 = 4,
Bit4 = 3,
Bit5 = 2,
T1 = ((1<<(Bit1+1))-1) ^ 0xFF, /* 0000 0000 */
Tx = ((1<<(Bitx+1))-1) ^ 0xFF, /* 1000 0000 */
T2 = ((1<<(Bit2+1))-1) ^ 0xFF, /* 1100 0000 */
T3 = ((1<<(Bit3+1))-1) ^ 0xFF, /* 1110 0000 */
T4 = ((1<<(Bit4+1))-1) ^ 0xFF, /* 1111 0000 */
T5 = ((1<<(Bit5+1))-1) ^ 0xFF, /* 1111 1000 */
Rune1 = (1<<(Bit1+0*Bitx))-1, /* 0000 0000 0000 0000 0111 1111 */
Rune2 = (1<<(Bit2+1*Bitx))-1, /* 0000 0000 0000 0111 1111 1111 */
Rune3 = (1<<(Bit3+2*Bitx))-1, /* 0000 0000 1111 1111 1111 1111 */
Rune4 = (1<<(Bit4+3*Bitx))-1, /* 0001 1111 1111 1111 1111 1111 */
Maskx = (1<<Bitx)-1, /* 0011 1111 */
Testx = Maskx ^ 0xFF, /* 1100 0000 */
Bad = Runeerror
};
int
chartorune(Rune *rune, const char *str)
{
int c, c1, c2, c3;
int l;
/* overlong null character */
if((uchar)str[0] == 0xc0 && (uchar)str[1] == 0x80) {
*rune = 0;
return 2;
}
/*
* one character sequence
* 00000-0007F => T1
*/
c = *(uchar*)str;
if(c < Tx) {
*rune = c;
return 1;
}
/*
* two character sequence
* 0080-07FF => T2 Tx
*/
c1 = *(uchar*)(str+1) ^ Tx;
if(c1 & Testx)
goto bad;
if(c < T3) {
if(c < T2)
goto bad;
l = ((c << Bitx) | c1) & Rune2;
if(l <= Rune1)
goto bad;
*rune = l;
return 2;
}
/*
* three character sequence
* 0800-FFFF => T3 Tx Tx
*/
c2 = *(uchar*)(str+2) ^ Tx;
if(c2 & Testx)
goto bad;
if(c < T4) {
l = ((((c << Bitx) | c1) << Bitx) | c2) & Rune3;
if(l <= Rune2)
goto bad;
*rune = l;
return 3;
}
/*
* four character sequence
* 10000-10FFFF => T4 Tx Tx Tx
*/
if(UTFmax >= 4) {
c3 = *(uchar*)(str+3) ^ Tx;
if(c3 & Testx)
goto bad;
if(c < T5) {
l = ((((((c << Bitx) | c1) << Bitx) | c2) << Bitx) | c3) & Rune4;
if(l <= Rune3)
goto bad;
if(l > Runemax)
goto bad;
*rune = l;
return 4;
}
}
/*
* bad decoding
*/
bad:
*rune = Bad;
return 1;
}
int
runetochar(char *str, const Rune *rune)
{
int c = *rune;
/* overlong null character */
if (c == 0) {
str[0] = (char)0xc0;
str[1] = (char)0x80;
return 2;
}
/*
* one character sequence
* 00000-0007F => 00-7F
*/
if(c <= Rune1) {
str[0] = c;
return 1;
}
/*
* two character sequence
* 00080-007FF => T2 Tx
*/
if(c <= Rune2) {
str[0] = T2 | (c >> 1*Bitx);
str[1] = Tx | (c & Maskx);
return 2;
}
/*
* three character sequence
* 00800-0FFFF => T3 Tx Tx
*/
if(c > Runemax)
c = Runeerror;
if(c <= Rune3) {
str[0] = T3 | (c >> 2*Bitx);
str[1] = Tx | ((c >> 1*Bitx) & Maskx);
str[2] = Tx | (c & Maskx);
return 3;
}
/*
* four character sequence
* 010000-1FFFFF => T4 Tx Tx Tx
*/
str[0] = T4 | (c >> 3*Bitx);
str[1] = Tx | ((c >> 2*Bitx) & Maskx);
str[2] = Tx | ((c >> 1*Bitx) & Maskx);
str[3] = Tx | (c & Maskx);
return 4;
}
int
runelen(int c)
{
Rune rune;
char str[10];
rune = c;
return runetochar(str, &rune);
}
int
utflen(const char *s)
{
int c;
int n;
Rune rune;
n = 0;
for(;;) {
c = *(uchar*)s;
if(c < Runeself) {
if(c == 0)
return n;
s++;
} else
s += chartorune(&rune, s);
n++;
}
}
static const Rune *
ucd_bsearch(Rune c, const Rune *t, int n, int ne)
{
const Rune *p;
int m;
while(n > 1) {
m = n/2;
p = t + m*ne;
if(c >= p[0]) {
t = p;
n = n-m;
} else
n = m;
}
if(n && c >= t[0])
return t;
return 0;
}
Rune
tolowerrune(Rune c)
{
const Rune *p;
p = ucd_bsearch(c, ucd_tolower2, nelem(ucd_tolower2)/3, 3);
if(p && c >= p[0] && c <= p[1])
return c + p[2];
p = ucd_bsearch(c, ucd_tolower1, nelem(ucd_tolower1)/2, 2);
if(p && c == p[0])
return c + p[1];
return c;
}
Rune
toupperrune(Rune c)
{
const Rune *p;
p = ucd_bsearch(c, ucd_toupper2, nelem(ucd_toupper2)/3, 3);
if(p && c >= p[0] && c <= p[1])
return c + p[2];
p = ucd_bsearch(c, ucd_toupper1, nelem(ucd_toupper1)/2, 2);
if(p && c == p[0])
return c + p[1];
return c;
}
int
islowerrune(Rune c)
{
const Rune *p;
p = ucd_bsearch(c, ucd_toupper2, nelem(ucd_toupper2)/3, 3);
if(p && c >= p[0] && c <= p[1])
return 1;
p = ucd_bsearch(c, ucd_toupper1, nelem(ucd_toupper1)/2, 2);
if(p && c == p[0])
return 1;
return 0;
}
int
isupperrune(Rune c)
{
const Rune *p;
p = ucd_bsearch(c, ucd_tolower2, nelem(ucd_tolower2)/3, 3);
if(p && c >= p[0] && c <= p[1])
return 1;
p = ucd_bsearch(c, ucd_tolower1, nelem(ucd_tolower1)/2, 2);
if(p && c == p[0])
return 1;
return 0;
}
int
isalpharune(Rune c)
{
const Rune *p;
p = ucd_bsearch(c, ucd_alpha2, nelem(ucd_alpha2)/2, 2);
if(p && c >= p[0] && c <= p[1])
return 1;
p = ucd_bsearch(c, ucd_alpha1, nelem(ucd_alpha1), 1);
if(p && c == p[0])
return 1;
return 0;
}