From cffa2eeb2052df70c52fc720add9fe7e31b314e7 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Thu, 5 Oct 2006 21:10:32 +0000
Subject: the big UCF-font commit! still a little bit messy, but it works quite
 well already more to come soon.

---
 ucf.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 ucf.c

(limited to 'ucf.c')

diff --git a/ucf.c b/ucf.c
new file mode 100644
index 0000000..baf9c48
--- /dev/null
+++ b/ucf.c
@@ -0,0 +1,133 @@
+/* uuterm, Copyright (C) 2006 Rich Felker; licensed under GNU GPL v2 only */
+
+/* note: the following implementation of ucf is NOT SECURE. malicious or
+ * damaged files can cause it to crash or possibly enter into an infinite
+ * loop, or cause other parts of the process core to be read as a font,
+ * possibly leading to information leaks. however there is no possibility
+ * of privilege elevation as ucf never writes to memory.
+ *
+ * users needing a robust implementation would be advised to simply run a
+ * sanity check across the whole font file before accepting it, rather than
+ * incurring large bounds-checking penalties at each glyph lookup.
+ */
+
+#include <stddef.h>
+#include "ucf.h"
+
+#define U24(p) ( ((p)[0]<<16) | ((p)[1]<<8) | (p)[2] )
+#define U32(p) ( ((p)[0]<<24) | U24((p)+1) )
+
+int ucf_init(struct ucf *f, const unsigned char *map, size_t len)
+{
+	size_t n;
+	if (memcmp(map, "ucf\300\000\001\000\000", 8))
+		return -1;
+	f->w = map[8];
+	f->h = map[9];
+	f->s = (f->w+7)>>3;
+	f->S = f->s * f->h;
+	f->ranges = map + U32(map+20) + 4;
+	f->gmap = map + U32(map+24);
+	f->glyphs = map + U32(map+28);
+	f->ctab = f->ranges + 8*(f->nranges = U32(f->ranges - 4));
+	return 0;
+}
+
+#define GMAP_WIDTH         1
+
+#define GMAP_FINAL1        0
+#define GMAP_FINAL2        1
+#define GMAP_GLYPH1        2
+#define GMAP_GLYPH2        3
+
+#define RULE_RANGE         4
+#define RULE_ATTACHED_TO   5
+#define RULE_WITH_ATTACHED 6
+#define RULE_FOLLOWS       7
+#define RULE_PRECEDES      8
+
+#define CTAB_MASK          0x3fffffff
+#define CTAB_INDIRECT      0x80000000
+#define CTAB_WIDTH         30
+
+int ucf_lookup(struct ucf *f, int idx, const unsigned *cc,
+	const unsigned *pc, const unsigned *nc, int width)
+{
+	unsigned ch = cc[idx];
+	unsigned a, l, x, i;
+	const unsigned *c;
+	const unsigned char *p;
+
+	for (p=f->ranges, a=0; ch>=(a+=U32(p)); p+=8) {
+		if (ch-a < (l=U32(p+4))) {
+			x = U32(f->ctab+4*(a-1));
+			if (x>>30 != width-1)
+				return -1;
+			return (x & 0x3fffffff) + (ch-a)*width;
+		}
+		ch -= l;
+	}
+	x = U32(f->ctab+4*ch);
+	if (!((x+1) & CTAB_INDIRECT)) {
+		if (x>>CTAB_WIDTH != width-1) return -1;
+		return x & CTAB_MASK;
+	}
+	x &= 0x7fffffff;
+	i = idx;
+	c = cc;
+	for (p=f->gmap+x; ; p+=4) {
+		if (*p <= GMAP_GLYPH2) {
+			if ((*p & GMAP_WIDTH) == width-1) break;
+			else if (*p <= GMAP_FINAL2) return -1;
+			i = idx; c = cc;
+			continue;
+		}
+		x = *p;
+		a = U24(p+1);
+		if (p[4] == RULE_RANGE) {
+			p += 4;
+			l = U24(p+1);
+		} else l = 1;
+		switch (x) {
+		case RULE_ATTACHED_TO:
+			if (i && c[--i]-a < l) continue;
+			break;
+		case RULE_WITH_ATTACHED:
+			if (c[++i]-a < l) continue;
+			break;
+		case RULE_FOLLOWS:
+			if ((c=pc)[i=0]-a < l) continue;
+			break;
+		case RULE_PRECEDES:
+			if ((c=nc)[i=0]-a < l) continue;
+			break;
+		}
+		/* Skip until the next mapping */
+		for (; *p > GMAP_GLYPH2; p+=4);
+		i = idx; c = cc;
+	}
+	return U24(p+1);
+}
+
+#if 0
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[])
+{
+	int i, j;
+	struct ucf f;
+	static char tmp[1000000];
+	ucf_init(&f, tmp, fread(tmp, 1, sizeof tmp, stdin));
+	for (i=1; i<argc; i++) {
+		unsigned x[5] = { strtol(argv[i], NULL, 16), 0 };
+		int g;
+		if (i+1<argc) x[1] = strtol(argv[i+1], NULL, 16);
+		printf("char %.4x maps to glyph %d\n", x[1], g=ucf_lookup(&f, 1, x, x+4, x+4, 1));
+		if (g >= 0) for (j=0; j<16; j++)
+			printf("%.2X", f.glyphs[16*g+j]);
+		printf("\n");
+	}
+	return 0;
+}
+#endif
-- 
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