Hash map implementation for wmem.

This has two expected uses:
- Many current users of wmem_tree don't actually need the predecessor lookup
  it provides (the lookup_le function family). A hash map provides straight
  insertion and lookup much more efficiently than a wmem_tree when predecessor
  lookup isn't needed.

- Many current users of glib's hash table and hash functions use untrusted data
  for keys, making them vulnerable to algorithmic complexity attacks. Care has
  been taken to make this implementation secure against such attacks, so it
  should be used whenever data is untrusted.

In my benchmarks it is measurably slower than GHashTable, but not excessively
so. Given the additional security it provides this seems like a reasonable
trade-off (and it is still faster than a wmem_tree).

Change-Id: I2d67a0d06029f14c153eaa42d5cfc774aefd9918
Reviewed-on: https://code.wireshark.org/review/1272
Reviewed-by: Evan Huus <eapache@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/epan/wmem/wmem_core.c b/epan/wmem/wmem_core.c
index d6ff486579..bcec1f78ad 100644
--- a/epan/wmem/wmem_core.c
+++ b/epan/wmem/wmem_core.c
@@ -27,6 +27,7 @@
 
 #include "wmem_core.h"
 #include "wmem_scopes.h"
+#include "wmem_map_int.h"
 #include "wmem_user_cb_int.h"
 #include "wmem_allocator.h"
 #include "wmem_allocator_simple.h"
@@ -206,6 +207,7 @@ wmem_init(void)
     }
 
     wmem_init_scopes();
+    wmem_init_hashing();
 }
 
 void