[sfnt] Fix charmap type 2 iterator (#52646).

The subsetted demo font of the report that exhibits the bug has a
very unusual type 2 cmap for Unicode(!): It contains only two
sub-headers, one for one-byte characters (covering the range 0x20 to
0xFA), and a second one for higher byte 0x01 (just for character
code U+0131).

Before this commit, the iterator wasn't able to correctly handle a
sub-header for higher byte 0x01.

* src/sfnt/ttcmap.c (tt_cmap2_char_next): Fix character increment
for outer loop.
This commit is contained in:
Werner Lemberg 2017-12-18 23:32:32 +01:00
parent bdab6578af
commit 2df73b397d
2 changed files with 28 additions and 2 deletions

View File

@ -1,3 +1,19 @@
2017-12-18 Werner Lemberg <wl@gnu.org>
[sfnt] Fix charmap type 2 iterator (#52646).
The subsetted demo font of the report that exhibits the bug has a
very unusual type 2 cmap for Unicode(!): It contains only two
sub-headers, one for one-byte characters (covering the range 0x20 to
0xFA), and a second one for higher byte 0x01 (just for character
code U+0131).
Before this commit, the iterator wasn't able to correctly handle a
sub-header for higher byte 0x01.
* src/sfnt/ttcmap.c (tt_cmap2_char_next): Fix character increment
for outer loop.
2017-12-18 Matthias Clasen <matthias.clasen@gmail.com>
[truetype] Minor code beautification.

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@ -547,9 +547,19 @@
}
}
/* jump to next sub-header, i.e. higher byte value */
/* If `charcode' is <= 0xFF, retry with `charcode + 1'. If */
/* `charcode' is 0x100 after the loop, do nothing since we have */
/* just reached the first sub-header for two-byte character codes. */
/* */
/* For all other cases, we jump to the next sub-header and adjust */
/* `charcode' accordingly. */
Next_SubHeader:
charcode = FT_PAD_FLOOR( charcode, 256 ) + 256;
if ( charcode <= 0xFF )
charcode++;
else if ( charcode == 0x100 )
;
else
charcode = FT_PAD_FLOOR( charcode, 0x100 ) + 0x100;
}
Exit: