commit 60e1fe550ae5d945c45a7ad04b46ec78da0309aa
author Florent Rougon <f.rougon@free.fr> Thu Jun 08 16:13:29 2017 +0200
committer Akira TAGOH <akira@tagoh.org> Mon Jun 12 17:03:37 2017 +0900
tree 16e2d74a9241a0b11855058580b452b56ce36966
parent 7940ada7a89115455b493e64f961e9c3d2cc5045

FcCharSetFreezeOrig(), FcCharSetFindFrozen(): use all buckets of freezer->orig_hash_table

As written at:

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

I think FcCharSetFreezeOrig() and FcCharSetFindFrozen() should use the %
operator instead of & when computing the bucket index for
freezer->orig_hash_table, otherwise at most 8 buckets among the 67
available (FC_CHAR_SET_HASH_SIZE) are used.

Another way would be to change FC_CHAR_SET_HASH_SIZE to be of the form
2**n -1 (i.e., a power of two minus one). In such a case, the & and %
operators would be equivalent.

src/fccharset.c

diff --git a/src/fccharset.c b/src/fccharset.c
index 6e69f66..69fbf66 100644
--- a/src/fccharset.c
+++ b/src/fccharset.c
@@ -1120,7 +1120,7 @@
 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];
+    FcCharSetOrigEnt	**bucket = &freezer->orig_hash_table[((uintptr_t) orig) % FC_CHAR_SET_HASH_SIZE];
     FcCharSetOrigEnt	*ent;
 
     ent = malloc (sizeof (FcCharSetOrigEnt));
@@ -1204,7 +1204,7 @@
 static const FcCharSet *
 FcCharSetFindFrozen (FcCharSetFreezer *freezer, const FcCharSet *orig)
 {
-    FcCharSetOrigEnt    **bucket = &freezer->orig_hash_table[((uintptr_t) orig) & FC_CHAR_SET_HASH_SIZE];
+    FcCharSetOrigEnt    **bucket = &freezer->orig_hash_table[((uintptr_t) orig) % FC_CHAR_SET_HASH_SIZE];
     FcCharSetOrigEnt	*ent;
 
     for (ent = *bucket; ent; ent = ent->next)