From 575707186d519303704f37cd958e530e20cf2c84 Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor@ghostscript.com>
Date: Wed, 18 Aug 2010 13:21:40 +0000
Subject: Put a hard limit on bezier subdivision in case precision limits make
 the flatness check fail.

---
 draw/pathfill.c       | 13 ++++++++-----
 draw/pathstroke.c     | 24 ++++++++++++++----------
 mupdf/pdf_interpret.c |  4 ++--
 3 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/draw/pathfill.c b/draw/pathfill.c
index 62d4ac59..f20f0946 100644
--- a/draw/pathfill.c
+++ b/draw/pathfill.c
@@ -1,5 +1,7 @@
 #include "fitz.h"
 
+#define MAXDEPTH 8
+
 static void
 line(fz_gel *gel, fz_matrix *ctm, float x0, float y0, float x1, float y1)
 {
@@ -15,7 +17,7 @@ bezier(fz_gel *gel, fz_matrix *ctm, float flatness,
 	float xa, float ya,
 	float xb, float yb,
 	float xc, float yc,
-	float xd, float yd)
+	float xd, float yd, int depth)
 {
 	float dmax;
 	float xab, yab;
@@ -30,7 +32,8 @@ bezier(fz_gel *gel, fz_matrix *ctm, float flatness,
 	dmax = MAX(dmax, ABS(ya - yb));
 	dmax = MAX(dmax, ABS(xd - xc));
 	dmax = MAX(dmax, ABS(yd - yc));
-	if (dmax < flatness) {
+	if (dmax < flatness || depth >= MAXDEPTH)
+	{
 		line(gel, ctm, xa, ya, xd, yd);
 		return;
 	}
@@ -59,8 +62,8 @@ bezier(fz_gel *gel, fz_matrix *ctm, float flatness,
 
 	xabcd *= 0.125f; yabcd *= 0.125f;
 
-	bezier(gel, ctm, flatness, xa, ya, xab, yab, xabc, yabc, xabcd, yabcd);
-	bezier(gel, ctm, flatness, xabcd, yabcd, xbcd, ybcd, xcd, ycd, xd, yd);
+	bezier(gel, ctm, flatness, xa, ya, xab, yab, xabc, yabc, xabcd, yabcd, depth + 1);
+	bezier(gel, ctm, flatness, xabcd, yabcd, xbcd, ybcd, xcd, ycd, xd, yd, depth + 1);
 }
 
 void
@@ -102,7 +105,7 @@ fz_fillpath(fz_gel *gel, fz_path *path, fz_matrix ctm, float flatness)
 			y2 = path->els[i++].v;
 			x3 = path->els[i++].v;
 			y3 = path->els[i++].v;
-			bezier(gel, &ctm, flatness, cx, cy, x1, y1, x2, y2, x3, y3);
+			bezier(gel, &ctm, flatness, cx, cy, x1, y1, x2, y2, x3, y3, 0);
 			cx = x3;
 			cy = y3;
 			break;
diff --git a/draw/pathstroke.c b/draw/pathstroke.c
index b68dcd4f..50343b3f 100644
--- a/draw/pathstroke.c
+++ b/draw/pathstroke.c
@@ -1,5 +1,7 @@
 #include "fitz.h"
 
+#define MAXDEPTH 8
+
 enum { BUTT = 0, ROUND = 1, SQUARE = 2, MITER = 0, BEVEL = 2 };
 
 struct sctx
@@ -336,7 +338,7 @@ fz_strokebezier(struct sctx *s,
 	float xa, float ya,
 	float xb, float yb,
 	float xc, float yc,
-	float xd, float yd)
+	float xd, float yd, int depth)
 {
 	float dmax;
 	float xab, yab;
@@ -351,7 +353,8 @@ fz_strokebezier(struct sctx *s,
 	dmax = MAX(dmax, ABS(ya - yb));
 	dmax = MAX(dmax, ABS(xd - xc));
 	dmax = MAX(dmax, ABS(yd - yc));
-	if (dmax < s->flatness) {
+	if (dmax < s->flatness || depth >= MAXDEPTH)
+	{
 		fz_point p;
 		p.x = xd;
 		p.y = yd;
@@ -383,8 +386,8 @@ fz_strokebezier(struct sctx *s,
 
 	xabcd *= 0.125f; yabcd *= 0.125f;
 
-	fz_strokebezier(s, xa, ya, xab, yab, xabc, yabc, xabcd, yabcd);
-	fz_strokebezier(s, xabcd, yabcd, xbcd, ybcd, xcd, ycd, xd, yd);
+	fz_strokebezier(s, xa, ya, xab, yab, xabc, yabc, xabcd, yabcd, depth + 1);
+	fz_strokebezier(s, xabcd, yabcd, xbcd, ybcd, xcd, ycd, xd, yd, depth + 1);
 }
 
 void
@@ -441,7 +444,7 @@ fz_strokepath(fz_gel *gel, fz_path *path, fz_strokestate *stroke, fz_matrix ctm,
 			p2.y = path->els[i++].v;
 			p3.x = path->els[i++].v;
 			p3.y = path->els[i++].v;
-			fz_strokebezier(&s, p0.x, p0.y, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+			fz_strokebezier(&s, p0.x, p0.y, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y, 0);
 			p0 = p3;
 			break;
 
@@ -522,7 +525,7 @@ fz_dashbezier(struct sctx *s,
 	float xa, float ya,
 	float xb, float yb,
 	float xc, float yc,
-	float xd, float yd)
+	float xd, float yd, int depth)
 {
 	float dmax;
 	float xab, yab;
@@ -537,7 +540,8 @@ fz_dashbezier(struct sctx *s,
 	dmax = MAX(dmax, ABS(ya - yb));
 	dmax = MAX(dmax, ABS(xd - xc));
 	dmax = MAX(dmax, ABS(yd - yc));
-	if (dmax < s->flatness) {
+	if (dmax < s->flatness || depth >= MAXDEPTH)
+	{
 		fz_point p;
 		p.x = xd;
 		p.y = yd;
@@ -569,8 +573,8 @@ fz_dashbezier(struct sctx *s,
 
 	xabcd *= 0.125f; yabcd *= 0.125f;
 
-	fz_dashbezier(s, xa, ya, xab, yab, xabc, yabc, xabcd, yabcd);
-	fz_dashbezier(s, xabcd, yabcd, xbcd, ybcd, xcd, ycd, xd, yd);
+	fz_dashbezier(s, xa, ya, xab, yab, xabc, yabc, xabcd, yabcd, depth + 1);
+	fz_dashbezier(s, xabcd, yabcd, xbcd, ybcd, xcd, ycd, xd, yd, depth + 1);
 }
 
 void
@@ -634,7 +638,7 @@ fz_dashpath(fz_gel *gel, fz_path *path, fz_strokestate *stroke, fz_matrix ctm, f
 			p2.y = path->els[i++].v;
 			p3.x = path->els[i++].v;
 			p3.y = path->els[i++].v;
-			fz_dashbezier(&s, p0.x, p0.y, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+			fz_dashbezier(&s, p0.x, p0.y, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y, 0);
 			p0 = p3;
 			break;
 
diff --git a/mupdf/pdf_interpret.c b/mupdf/pdf_interpret.c
index f33a7ef4..e8cdf20d 100644
--- a/mupdf/pdf_interpret.c
+++ b/mupdf/pdf_interpret.c
@@ -1330,7 +1330,7 @@ defaultcase:
 	return fz_okay;
 
 syntaxerror:
-	return fz_throw("syntaxerror near '%s'", buf);
+	return fz_throw("syntax error near '%s' with %d items on the stack", buf, csi->top);
 }
 
 static fz_error
@@ -1460,7 +1460,7 @@ pdf_runcsifile(pdf_csi *csi, fz_obj *rdb, fz_stream *file, char *buf, int buflen
 			{
 				error = pdf_runkeyword(csi, rdb, buf);
 				if (error)
-					return fz_rethrow(error, "cannot run '%s'", buf);
+					return fz_rethrow(error, "cannot run keyword '%s'", buf);
 				pdf_clearstack(csi);
 			}
 			break;
-- 
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