ref: 4d69aacea023546a7150d92e147e531c38de822f
dir: /sys/src/libttf/cmap.c/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ttf.h>
#include "impl.h"
int
ttffindchar(TTFont *fx, Rune r)
{
int i, j, k, rv;
TTChMap *p;
TTFontU *f;
f = fx->u;
i = 0;
j = f->ncmap - 1;
if(r < f->cmap[0].start || r > f->cmap[j].end) return 0;
while(i < j){
k = (i + j) / 2;
if(f->cmap[k].end < r)
i = k+1;
else if(f->cmap[k].start > r)
j = k-1;
else
i = j = k;
}
if(i > j) return 0;
p = &f->cmap[i];
if(r < p->start || r > p->end) return 0;
if((p->flags & TTCINVALID) != 0) return 0;
if(p->tab != nil)
return p->tab[r - p->start];
rv = r + p->delta;
if((p->flags & TTCDELTA16) != 0)
rv = (u16int)rv;
return rv;
}
int
ttfenumchar(TTFont *fx, Rune r, Rune *rp)
{
int i, j, k, rv;
TTChMap *p;
TTFontU *f;
f = fx->u;
i = 0;
j = f->ncmap - 1;
if(r > f->cmap[j].end) return 0;
while(i < j){
k = (i + j) / 2;
if(f->cmap[k].end < r)
i = k+1;
else if(f->cmap[k].start > r)
j = k-1;
else
i = j = k;
}
if(j < 0) j = 0;
for(p = &f->cmap[j]; p < &f->cmap[f->ncmap]; p++){
if((p->flags & TTCINVALID) != 0)
continue;
if(r < p->start)
r = p->start;
if(p->tab != nil){
SET(rv);
while(r <= p->end && (rv = p->tab[r - p->start], rv == 0))
r++;
if(r > p->end)
continue;
if(rp != nil)
*rp = r;
return rv;
}
while(r < p->end){
rv = r + p->delta;
if((p->flags & TTCDELTA16) != 0)
rv = (u16int) rv;
if(rv != 0){
if(rp != nil)
*rp = r;
return rv;
}
}
}
return 0;
}
static int
ttfgotosub(TTFontU *f)
{
int i;
u16int nsub, id, sid;
int rank, maxrank;
u32int maxoff, off;
#define SUBID(a,b) ((a)<<16|(b))
if(ttfgototable(f, "cmap") < 0)
return -1;
ttfunpack(f, ".. w", &nsub);
maxrank = 0;
maxoff = 0;
for(i = 0; i < nsub; i++){
ttfunpack(f, "wwl", &id, &sid, &off);
switch(id << 16 | sid){
case SUBID(0, 4): /* Unicode 2.0 or later (BMP and non-BMP) */
rank = 100;
break;
case SUBID(3, 10): /* Windows, UCS-4 */
rank = 80;
break;
case SUBID(0, 0): /* Unicode default */
case SUBID(0, 1): /* Unicode 1.1 */
case SUBID(0, 2): /* ISO 10646 */
case SUBID(0, 3): /* Unicode 2.0 (BMP) */
rank = 60;
break;
case SUBID(3, 1): /* Windows, UCS-2 */
rank = 40;
break;
case SUBID(3, 0): /* Windows, Symbol */
rank = 20;
break;
default:
rank = 0;
break;
}
if(rank > maxrank){
maxrank = rank;
maxoff = off;
}
}
if(maxrank == 0){
werrstr("no suitable character table");
return -1;
}
if(ttfgototable(f, "cmap") < 0)
return -1;
Bseek(f->bin, maxoff, 1);
return 0;
}
static int
cmap0(TTFontU *f)
{
u16int len;
int i;
u8int *p;
int *q;
ttfunpack(f, "w2", &len);
if(len < 262){
werrstr("character table too short");
return -1;
}
f->cmap = mallocz(sizeof(TTChMap), 1);
if(f->cmap == nil)
return -1;
f->ncmap = 1;
f->cmap->start = 0;
f->cmap->end = 0xff;
f->cmap->tab = mallocz(256 * sizeof(int), 1);
if(f->cmap->tab == nil)
return -1;
Bread(f->bin, f->cmap->tab, 256 * sizeof(int));
p = (u8int*)f->cmap->tab + 256;
q = f->cmap->tab + 256;
for(i = 255; i >= 0; i--)
*--q = *--p;
return 0;
}
static int
cmap4(TTFontU *f)
{
u16int len, ncmap;
int i, j, n, n0, off;
u16int v;
u8int *buf;
ttfunpack(f, "w2", &len);
if(len < 16){
werrstr("character table too short");
return -1;
}
ttfunpack(f, "w6", &ncmap);
ncmap /= 2;
if(len < 16 + 8 * ncmap){
werrstr("character table too short");
return -1;
}
f->cmap = mallocz(sizeof(TTChMap) * ncmap, 1);
if(f->cmap == nil) return -1;
f->ncmap = ncmap;
for(i = 0; i < ncmap; i++)
f->cmap[i].flags = TTCDELTA16;
for(i = 0; i < ncmap; i++)
ttfunpack(f, "W", &f->cmap[i].end);
ttfunpack(f, "..");
for(i = 0; i < ncmap; i++)
ttfunpack(f, "W", &f->cmap[i].start);
for(i = 0; i < ncmap; i++)
ttfunpack(f, "W", &f->cmap[i].delta);
for(i = 0; i < ncmap; i++)
ttfunpack(f, "W", &f->cmap[i].temp);
len -= 10 + 8 * ncmap;
buf = malloc(len);
if(buf == nil)
return -1;
Bread(f->bin, buf, len);
for(i = 0; i < ncmap; i++){
if(f->cmap[i].temp == 0) continue;
n0 = f->cmap[i].end - f->cmap[i].start + 1;
n = n0;
off = f->cmap[i].temp - (ncmap - i) * 2;
if(off + 2 * n > len) n = (len - off) / 2;
if(off < 0 || n <= 0){
f->cmap[i].flags |= TTCINVALID;
continue;
}
f->cmap[i].tab = mallocz(n0 * sizeof(int), 1);
if(f->cmap[i].tab == nil)
return -1;
for(j = 0; j < n; j++){
v = buf[off + 2*j] << 8 | buf[off + 2*j + 1];
if(v != 0) v += f->cmap[i].delta;
f->cmap[i].tab[j] = v;
}
}
free(buf);
return 0;
}
static int
cmap6(TTFontU *f)
{
u16int len, first, cnt, v;
int *p;
u8int *q;
ttfunpack(f, "w2", &len);
if(len < 12){
werrstr("character table too short");
return -1;
}
ttfunpack(f, "ww", &first, &cnt);
f->cmap = mallocz(sizeof(TTChMap), 1);
if(f->cmap == nil)
return -1;
f->ncmap = 1;
f->cmap->start = first;
f->cmap->end = first + len - 1;
f->cmap->tab = mallocz(cnt * sizeof(int), 1);
if(f->cmap->tab == nil)
return -1;
if(len < 10 + 2 * cnt){
werrstr("character table too short");
return -1;
}
Bread(f->bin, f->cmap->tab, 2 * cnt);
p = f->cmap->tab + cnt;
q = (u8int*) f->cmap->tab + 2 * cnt;
while(p > f->cmap->tab){
v = *--q;
v |= *--q << 8;
*--p = v;
}
return 0;
}
static int
cmap12(TTFontU *f)
{
u32int len;
u32int ncmap;
int i;
ttfunpack(f, "2l4", &len);
if(len < 16){
werrstr("character table too short");
return -1;
}
ttfunpack(f, "l", &ncmap);
if(len < 16 + 12 * ncmap){
werrstr("character table too short");
return -1;
}
f->cmap = mallocz(sizeof(TTChMap) * ncmap, 1);
if(f->cmap == nil)
return -1;
f->ncmap = ncmap;
for(i = 0; i < ncmap; i++){
ttfunpack(f, "lll", &f->cmap[i].start, &f->cmap[i].end, &f->cmap[i].delta);
f->cmap[i].delta -= f->cmap[i].start;
}
return 0;
}
int (*cmaphand[])(TTFontU *) = {
[0] cmap0,
[4] cmap4,
[6] cmap6,
[12] cmap12,
};
int
ttfparsecmap(TTFontU *f)
{
u16int format;
if(ttfgotosub(f) < 0)
return -1;
ttfunpack(f, "w", &format);
if(format >= nelem(cmaphand) || cmaphand[format] == nil){
werrstr("character table in unknown format %d", format);
return -1;
}
if(cmaphand[format](f) < 0)
return -1;
return 0;
}