add libttf

1 files changed, 322 insertions, 0 deletions

diff --git a/sys/src/libttf/cmap.c b/sys/src/libttf/cmap.c
new file mode 100644
index 000000000..94092f03e
--- /dev/null
+++ b/sys/src/libttf/cmap.c
@@ -0,0 +1,322 @@
+#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, off;
+	int rank, maxrank;
+	u32int maxoff;
+	#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(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 = 80;
+			break;
+		case SUBID(3, 10): /* Windows, UCS-4 */
+			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;
+}