1 files changed, 58 insertions, 0 deletions
diff --git a/repo/system/cairo/pdf-font-subset-Generate-valid-font-names.patch b/repo/system/cairo/pdf-font-subset-Generate-valid-font-names.patch
new file mode 100644
index 0000000..d5cfe2f
--- /dev/null
+++ b/repo/system/cairo/pdf-font-subset-Generate-valid-font-names.patch
@@ -0,0 +1,58 @@
+From a3b69a0215fdface0fd5730872a4b3242d979dca Mon Sep 17 00:00:00 2001
+From: Uli Schlachter <psychon@znc.in>
+Date: Tue, 9 Feb 2021 16:54:35 +0100
+Subject: [PATCH] pdf font subset: Generate valid font names
+
+A hash value is encoded in base 26 with upper case letters for font
+names.
+
+Commit ed984146 replaced "numerator = abs (hash);" with "numerator =
+hash;" in this code, because hash has type uint32_t and the compiler
+warned about taking the absolute value of an unsigned value.  However,
+abs() is actually defined to take an int argument. Thus, there was some
+implicit cast.
+
+Since numerator has type long, i.e. is signed, it is now actually
+possible to get an overflow in the implicit cast and then have a
+negative number. The following code is not prepared for this and
+produces non-letters when encoding the hash.
+
+This commit fixes that problem by not using ldiv() and instead using /
+and % to directly compute the needed values. This gets rid of the need
+to convert to type long. Since now everything works with uint32_t, there
+is no more chance for negative numbers messing things up.
+
+Fixes: https://gitlab.freedesktop.org/cairo/cairo/-/issues/449
+Signed-off-by: Uli Schlachter <psychon@znc.in>
+---
+ src/cairo-pdf-surface.c | 8 ++------
+ 1 file changed, 2 insertions(+), 6 deletions(-)
+
+diff --git a/src/cairo-pdf-surface.c b/src/cairo-pdf-surface.c
+index 6da460878..52c49b6d2 100644
+--- a/src/cairo-pdf-surface.c
++++ b/src/cairo-pdf-surface.c
+@@ -5310,18 +5310,14 @@ _create_font_subset_tag (cairo_scaled_font_subset_t	*font_subset,
+ {
+     uint32_t hash;
+     int i;
+-    long numerator;
+-    ldiv_t d;
+ 
+     hash = _hash_data ((unsigned char *) font_name, strlen(font_name), 0);
+     hash = _hash_data ((unsigned char *) (font_subset->glyphs),
+ 		       font_subset->num_glyphs * sizeof(unsigned long), hash);
+ 
+-    numerator = hash;
+     for (i = 0; i < 6; i++) {
+-	d = ldiv (numerator, 26);
+-	numerator = d.quot;
+-        tag[i] = 'A' + d.rem;
++	tag[i] = 'A' + (hash % 26);
++	hash /= 26;
+     }
+     tag[i] = 0;
+ }
+-- 
+GitLab
+