add libttf

1 files changed, 344 insertions, 0 deletions

diff --git a/sys/src/libttf/head.c b/sys/src/libttf/head.c
new file mode 100644
index 000000000..9a50c7f16
--- /dev/null
+++ b/sys/src/libttf/head.c
@@ -0,0 +1,344 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include <draw.h>
+#include <ctype.h>
+#include <ttf.h>
+#include "impl.h"
+
+void
+ttfunpack(TTFontU *f, char *p, ...)
+{
+	va_list va;
+	int n;
+	uchar *p1;
+	u16int *p2;
+	u32int *p4;
+	
+	va_start(va, p);
+	for(; *p != 0; p++)
+		switch(*p){
+		case 'b':
+			p1 = va_arg(va, u8int *);
+			*p1 = Bgetc(f->bin);
+			break;
+		case 'B':
+			p4 = va_arg(va, u32int *);
+			*p4 = Bgetc(f->bin);
+			break;
+		case 'w':
+			p2 = va_arg(va, u16int *);
+			*p2 = Bgetc(f->bin) << 8;
+			*p2 |= Bgetc(f->bin);
+			break;
+		case 'W':
+			p4 = va_arg(va, u32int *);
+			*p4 = Bgetc(f->bin) << 8;
+			*p4 |= Bgetc(f->bin);
+			break;
+		case 'S':
+			p4 = va_arg(va, u32int *);
+			*p4 = (char)Bgetc(f->bin) << 8;
+			*p4 |= Bgetc(f->bin);
+			break;
+		case 'l':
+			p4 = va_arg(va, u32int *);
+			*p4 = Bgetc(f->bin) << 24;
+			*p4 |= Bgetc(f->bin) << 16;
+			*p4 |= Bgetc(f->bin) << 8;
+			*p4 |= Bgetc(f->bin);
+			break;
+		case '.': Bgetc(f->bin); break;
+		case ' ': break;
+		default:
+			if(isdigit(*p)){
+				n = strtol(p, &p, 10);
+				p--;
+				Bseek(f->bin, n, 1);
+			}else abort();
+			break;
+		}
+}
+
+static int
+directory(TTFontU *f)
+{
+	u32int scaler;
+	int i;
+
+	ttfunpack(f, "lw .. .. ..", &scaler, &f->ntab);
+	if(scaler != 0x74727565 && scaler != 0x10000){
+		werrstr("unknown scaler type %#ux", scaler);
+		return -1;
+	}
+	f->tab = mallocz(sizeof(TTTable) * f->ntab, 1);
+	if(f->tab == nil) return -1;
+	for(i = 0; i < f->ntab; i++)
+		ttfunpack(f, "llll", &f->tab[i].tag, &f->tab[i].csum, &f->tab[i].offset, &f->tab[i].len);
+	return 0;
+}
+
+int
+ttfgototable(TTFontU *f, char *str)
+{
+	TTTable *t;
+	u32int tag;
+	
+	tag = (u8int)str[0] << 24 | (u8int)str[1] << 16 | (u8int)str[2] << 8 | (u8int)str[3];
+	for(t = f->tab; t < f->tab + f->ntab; t++)
+		if(t->tag == tag){
+			Bseek(f->bin, t->offset, 0);
+			return t->len;
+		}
+	werrstr("no such table '%s'", str);
+	return -1;
+}
+
+static int
+ttfparseloca(TTFontU *f)
+{
+	int len, i;
+	u32int x;
+	
+	len = ttfgototable(f, "loca");
+	if(len < 0) return -1;
+	x = 0;
+	if(f->longloca){
+		if(len > (f->numGlyphs + 1) * 4) len = (f->numGlyphs + 1) * 4;
+		for(i = 0; i < len/4; i++){
+			x = Bgetc(f->bin) << 24;
+			x |= Bgetc(f->bin) << 16;
+			x |= Bgetc(f->bin) << 8;
+			x |= Bgetc(f->bin);
+			f->ginfo[i].loca = x;
+		}
+	}else{
+		if(len > (f->numGlyphs + 1) * 2) len = (f->numGlyphs + 1) * 2;
+		for(i = 0; i < len/2; i++){
+			x = Bgetc(f->bin) << 8;
+			x |= Bgetc(f->bin);
+			f->ginfo[i].loca = x * 2;
+		}
+	}
+	for(; i < f->numGlyphs; i++)
+		f->ginfo[i].loca = x;
+	return 0;
+}
+
+static int
+ttfparsehmtx(TTFontU *f)
+{
+	int i;
+	u16int x, y;
+	int len;
+	int maxlsb;
+	
+	len = ttfgototable(f, "hmtx");
+	if(len < 0)
+		return -1;
+	if(f->numOfLongHorMetrics > f->numGlyphs){
+		werrstr("nonsensical header: numOfLongHorMetrics > numGlyphs");
+		return -1;
+	}
+	for(i = 0; i < f->numOfLongHorMetrics; i++){
+		ttfunpack(f, "ww", &x, &y);
+		f->ginfo[i].advanceWidth = x;
+		f->ginfo[i].lsb = y;
+	}
+	maxlsb = (len - 2 * f->numOfLongHorMetrics) / 2;
+	if(maxlsb > f->numGlyphs){
+		werrstr("nonsensical header: maxlsb > f->numGlyphs");
+		return -1;
+	}
+	for(; i < maxlsb; i++){
+		ttfunpack(f, "w", &y);
+		f->ginfo[i].advanceWidth = x;
+		f->ginfo[i].lsb = y;
+	}
+	for(; i < f->numGlyphs; i++){
+		f->ginfo[i].advanceWidth = x;
+		f->ginfo[i].lsb = y;
+	}
+	return 0;
+}
+
+int
+ttfparsecvt(TTFontU *f)
+{
+	int len;
+	int i;
+	int x;
+	u8int *p;
+	short *w;
+
+	len = ttfgototable(f, "cvt ");
+	if(len <= 0) return 0;
+	f->cvtu = mallocz(len, 1);
+	if(f->cvtu == 0) return -1;
+	Bread(f->bin, f->cvtu, len);
+	p = (u8int *) f->cvtu;
+	f->ncvtu = len / 2;
+	w = f->cvtu;
+	for(i = 0; i < f->ncvtu; i++){
+		x = (short)(p[0] << 8 | p[1]);
+		p += 2;
+		*w++ = x;
+	}
+	return 0;
+}
+
+static int
+ttfparseos2(TTFontU *f)
+{
+	int len;
+	u16int usWinAscent, usWinDescent;
+	
+	len = ttfgototable(f, "OS/2 ");
+	if(len < 0)
+		return -1;
+	if(len < 78){
+		werrstr("OS/2 table too short");
+		return -1;
+	}
+	ttfunpack(f, "68 6 ww", &usWinAscent, &usWinDescent);
+	f->ascent = usWinAscent;
+	f->descent = usWinDescent;
+	return 0;
+}
+
+static void
+ttfcloseu(TTFontU *u)
+{
+	int i;
+
+	if(u == nil) return;
+	Bterm(u->bin);
+	for(i = 0; i < u->ncmap; i++)
+		free(u->cmap[i].tab);
+	free(u->cmap);
+	free(u->ginfo);
+	free(u->tab);
+	free(u->cvtu);
+	free(u);
+}
+
+void
+ttfclose(TTFont *f)
+{
+	int i;
+
+	if(f == nil) return;
+	if(--f->u->ref <= 0)
+		ttfcloseu(f->u);
+	for(i = 0; i < f->u->maxFunctionDefs; i++)
+		free(f->func[i].pgm);
+	free(f->hintstack);
+	free(f->func);
+	free(f->storage);
+	free(f->twilight);
+	free(f->twiorg);
+	free(f->cvt);
+	free(f);
+}
+
+static TTFont *
+ttfscaleu(TTFontU *u, int ppem)
+{
+	TTFont *f;
+	int i;
+	
+	f = mallocz(sizeof(TTFont), 1);
+	if(f == nil) return nil;
+	f->u = u;
+	u->ref++;
+	f->ppem = ppem;
+	f->ncvt = u->ncvtu;
+	f->cvt = malloc(sizeof(int) * u->ncvtu);
+	if(f->cvt == nil) goto error;
+	for(i = 0; i < u->ncvtu; i++)
+		f->cvt[i] = ttfrounddiv(u->cvtu[i] * ppem * 64, u->emsize);
+	f->hintstack = mallocz(sizeof(u32int) * u->maxStackElements, 1);
+	f->func = mallocz(sizeof(TTFunction) * u->maxFunctionDefs, 1);
+	f->storage = mallocz(sizeof(u32int) * u->maxStorage, 1);
+	f->twilight = mallocz(sizeof(TTPoint) * u->maxTwilightPoints, 1);
+	f->twiorg = mallocz(sizeof(TTPoint) * u->maxTwilightPoints, 1);
+	if(f->hintstack == nil || f->func == nil || f->storage == nil || f->twilight == nil || f->twiorg == nil) goto error;
+	f->ascentpx = (u->ascent * ppem + u->emsize - 1) / (u->emsize);
+	f->descentpx = (u->descent * ppem + u->emsize - 1) / (u->emsize);
+	if(ttfrunfpgm(f) < 0) goto error;
+	if(ttfruncvt(f) < 0) goto error;
+	return f;
+
+error:
+	ttfclose(f);
+	return nil;
+}
+
+TTFont *
+ttfopen(char *name, int ppem, int)
+{
+	Biobuf *b;
+	TTFontU *u;
+	
+	if(ppem < 0){
+		werrstr("invalid ppem argument");
+		return nil;
+	}
+	b = Bopen(name, OREAD);
+	if(b == nil)
+		return nil;
+	u = mallocz(sizeof(TTFontU), 1);
+	if(u == nil)
+		return nil;
+	u->bin = b;
+	u->nkern = -1;
+	directory(u);
+	if(ttfgototable(u, "head") < 0) goto error;
+	ttfunpack(u, "16 w W 16 wwww 6 w", &u->flags, &u->emsize, &u->xmin, &u->ymin, &u->xmax, &u->ymax, &u->longloca);
+	if(ttfgototable(u, "maxp") < 0) goto error;
+	ttfunpack(u, "4 wwwwwwwwwwwwww",
+		&u->numGlyphs, &u->maxPoints, &u->maxCountours, &u->maxComponentPoints, &u->maxComponentCountours,
+		&u->maxZones, &u->maxTwilightPoints, &u->maxStorage, &u->maxFunctionDefs, &u->maxInstructionDefs,
+		&u->maxStackElements, &u->maxSizeOfInstructions, &u->maxComponentElements, &u->maxComponentDepth);
+	u->ginfo = mallocz(sizeof(TTGlyphInfo) * (u->numGlyphs + 1), 1);
+	if(u->ginfo == nil)
+		goto error;
+	if(ttfgototable(u, "hhea") < 0) goto error;
+	ttfunpack(u, "10 wwww 16 w", &u->advanceWidthMax, &u->minLeftSideBearing, &u->minRightSideBearing, &u->xMaxExtent, &u->numOfLongHorMetrics);
+	if(ttfparseloca(u) < 0) goto error;
+	if(ttfparsehmtx(u) < 0) goto error;
+	if(ttfparsecvt(u) < 0) goto error;
+	if(ttfparsecmap(u) < 0) goto error;
+	if(ttfparseos2(u) < 0) goto error;
+	return ttfscaleu(u, ppem);
+
+error:
+	ttfcloseu(u);
+	return nil;
+}
+
+TTFont *
+ttfscale(TTFont *f, int ppem, int)
+{
+	return ttfscaleu(f->u, ppem);
+}
+
+int
+ttfrounddiv(int a, int b)
+{
+	if(b < 0){ a = -a; b = -b; }
+	if(a > 0)
+		return (a + b/2) / b;
+	else
+		return (a - b/2) / b;
+}
+
+int
+ttfvrounddiv(vlong a, int b)
+{
+	if(b < 0){ a = -a; b = -b; }
+	if(a > 0)
+		return (a + b/2) / b;
+	else
+		return (a - b/2) / b;
+}