Re: [Devel] freetype infinite looping

[Werner LEMBERG]

> When run on an unusual truetype file, I can get freetype 2.0.4 and
> later to get into an infinite loop. I think something is wrong with
> the truetype file, but I can't figure out what.

In any case, it is a bug in the autohinter.  I don't get an infinite
loop but a segfault.  Here a backtrace from

  ftview 40 flunk.ttf


Program received signal SIGSEGV, Segmentation fault.
0x0805466a in ah_outline_compute_segments (outline=0x80a8af8)
    at /home/ft/freetype2/src/autohint/ahglyph.c:739
739             if ( ABS( last->out_dir )  == major_dir &&
(gdb) p last
$1 = (AH_Point *) 0x0
(gdb) bt
#0  0x0805466a in ah_outline_compute_segments (outline=0x80a8af8)
    at /home/ft/freetype2/src/autohint/ahglyph.c:739
#1  0x080551c2 in ah_outline_detect_features (outline=0x80a8af8)
    at /home/ft/freetype2/src/autohint/ahglyph.c:1296
#2  0x0805776c in ah_hinter_load (hinter=0x80a8aa8, glyph_index=3,
    load_flags=2049, depth=0) at /home/ft/freetype2/src/autohint/ahhint.c:1096
#3  0x08057e79 in ah_hinter_load_glyph (hinter=0x80a8aa8, slot=0x80b32c8,
    size=0x80b33f0, glyph_index=3, load_flags=2049)
    at /home/ft/freetype2/src/autohint/ahhint.c:1362
#4  0x08058025 in ft_autohinter_load (module=0x80a8a88, slot=0x80b32c8,
    size=0x80b33f0, glyph_index=3, load_flags=4)
    at /home/ft/freetype2/src/autohint/ahmodule.c:73
#5  0x0804d22f in FT_Load_Glyph (face=0x80afa58, glyph_index=3, load_flags=4)
    at /home/ft/freetype2/src/base/ftobjs.c:888
#6  0x0805a90e in ftc_sbit_node_load (snode=0x80b3530, manager=0x80a9e90,
    sfam=0x80b3478, gindex=3, asize=0xbffff3a4)
    at /home/ft/freetype2/src/cache/ftcsbits.c:189
#7  0x0805aca1 in ftc_sbit_node_compare (snode=0x80b3530, squery=0xbffff450,
    cache=0x80a9f48) at /home/ft/freetype2/src/cache/ftcsbits.c:342
#8  0x08059dd8 in ftc_cache_lookup (cache=0x80a9f48, query=0xbffff450,
    anode=0xbffff44c) at /home/ft/freetype2/src/cache/ftccache.c:528
#9  0x0805aeed in FTC_SBitCache_Lookup (cache=0x80a9f48, desc=0x809886c,
    gindex=3, ansbit=0xbffff4b8, anode=0x0)
    at /home/ft/freetype2/src/cache/ftcsbits.c:481
#10 0x08049b00 in get_glyph_bitmap (Index=3, target=0xbffff504,
    left=0xbffff4f8, top=0xbffff4f4, x_advance=0xbffff4f0,
    y_advance=0xbffff4ec, aglyf=0xbffff520) at src/ftcommon.i:507
#11 0x08049e14 in Render_All (first_index=0) at src/ftview.c:59
#12 0x0804aacf in main (argc=0, argv=0xbffff610) at src/ftview.c:502
#13 0x401427ee in __libc_start_main () from /lib/libc.so.6


    Werner