diff options
Diffstat (limited to 'repo/cairo/pdf-font-subset-Generate-valid-font-names.patch')
| -rw-r--r-- | repo/cairo/pdf-font-subset-Generate-valid-font-names.patch | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/repo/cairo/pdf-font-subset-Generate-valid-font-names.patch b/repo/cairo/pdf-font-subset-Generate-valid-font-names.patch new file mode 100644 index 0000000..d5cfe2f --- /dev/null +++ b/repo/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 + |