Bug 101352

Created attachment 131807 [details] [review]
Possible fix in 'git format-patch' format

Hello,

As written at: https://lists.freedesktop.org/archives/fontconfig/2017-June/005929.html

The following looks odd to me in src/fccharset.c:

#define FC_CHAR_SET_HASH_SIZE    67

[...]

static FcBool
FcCharSetFreezeOrig (FcCharSetFreezer *freezer, const FcCharSet *orig, const FcCharSet *frozen)
{
    FcCharSetOrigEnt	**bucket = &freezer->orig_hash_table[((uintptr_t) orig) & FC_CHAR_SET_HASH_SIZE];

[...]

static const FcCharSet *
FcCharSetFindFrozen (FcCharSetFreezer *freezer, const FcCharSet *orig)
{
    FcCharSetOrigEnt    **bucket = &freezer->orig_hash_table[((uintptr_t) orig) & FC_CHAR_SET_HASH_SIZE];

[...]

It seems to me that either FC_CHAR_SET_HASH_SIZE should be defined as a
power of two minus one (2**n - 1 for some n), or the two occurrences of
the & operator in the above lines should be replaced with a % operator.
Otherwise, at most 8 buckets among the 67 available in
freezer->orig_hash_table can effectively be used
(67 = 64 + 2 + 1 and 2**3 = 8).