More Hashing methods

[awesomized/libmemcached] / lib / memcached_hash.c

diff --git a/lib/memcached_hash.c b/lib/memcached_hash.c
index 073b0c5d81b606f6a9f7730dd326b448eee5c88e..0d83cb75a7d0b0591b9ae4f2cbb8c0ccbd960862 100644 (file)
--- a/lib/memcached_hash.c
+++ b/lib/memcached_hash.c
@@ -1,20 +1,84 @@
 #include "common.h"
 
+/* Defines */
+static uint64_t FNV_64_INIT= 0xcbf29ce484222325L;
+static uint64_t FNV_64_PRIME= 0x100000001b3L;
+
+static uint32_t FNV_32_INIT= 2166136261L;
+static uint32_t FNV_32_PRIME= 16777619;
+
 /* Prototypes */
 static unsigned int internal_generate_hash(char *key, size_t key_length);
 static uint32_t internal_generate_md5(char *key, size_t key_length);
+static uint32_t internal_generate_md5(char *key, size_t key_length);
+static uint32_t internal_generate_ketama_md5(char *key, size_t key_length);
 
 unsigned int memcached_generate_hash(memcached_st *ptr, char *key, size_t key_length)
 {
   uint32_t hash;
+  unsigned int x;
 
-  if (ptr->flags & MEM_USE_MD5)
-    hash= internal_generate_md5(key, key_length);
-  else if (ptr->flags & MEM_USE_CRC)
-    hash= hash_crc32(key, key_length);
-  else
+  switch (ptr->hash)
+  {
+  case MEMCACHED_HASH_DEFAULT:
     hash= internal_generate_hash(key, key_length);
+    break;
+  case MEMCACHED_HASH_MD5:
+    hash= internal_generate_md5(key, key_length);
+    break;
+  case MEMCACHED_HASH_CRC:
+    hash= ((hash_crc32(key, key_length) >> 16) & 0x7fff);
+    break;
+    /* FNV hash'es lifted from Dustin Sallings work */
+  case MEMCACHED_HASH_FNV1_64: 
+    {
+      /* Thanks to pierre@demartines.com for the pointer */
+      hash = FNV_64_INIT;
+      for (x= 0; x < key_length; x++) 
+      {
+        hash *= FNV_64_PRIME;
+        hash ^= key[x];
+      }
+    }
+    break;
+  case MEMCACHED_HASH_FNV1A_64: 
+    {
+      hash= FNV_64_INIT;
+      for (x= 0; x < key_length; x++) 
+      {
+        hash ^= key[x];
+        hash *= FNV_64_PRIME;
+      }
+    }
+    break;
+  case MEMCACHED_HASH_FNV1_32: 
+    {
+      hash= FNV_32_INIT;
+      for (x= 0; x < key_length; x++) 
+      {
+        hash *= FNV_32_PRIME;
+        hash ^= key[x];
+      }
+    }
+    break;
+  case MEMCACHED_HASH_FNV1A_32: 
+    {
+      hash= FNV_32_INIT;
+      for (x= 0; x < key_length; x++) 
+      {
+        hash ^= key[x];
+        hash *= FNV_32_PRIME;
+      }
+    }
+    break;
+    case MEMCACHED_HASH_KETAMA: 
+    {
+      hash= internal_generate_ketama_md5(key, key_length);
+      break;
+    }
+  }
 
+  WATCHPOINT_ASSERT(hash);
   if (ptr->flags & MEM_USE_KETAMA)
   {
     WATCHPOINT_ASSERT(0);
@@ -53,3 +117,15 @@ static uint32_t internal_generate_md5(char *key, size_t key_length)
                     | ( results[1] <<  8 )
                     |   results[0] );
 }
+
+static uint32_t internal_generate_ketama_md5(char *key, size_t key_length)
+{
+  unsigned char results[16];
+
+  md5_signature((unsigned char*)key, (unsigned int)key_length, results);
+
+  return ((uint32_t) (results[3] & 0xFF) << 24)
+    | ((uint32_t) (results[2] & 0xFF) << 16)
+    | ((uint32_t) (results[1] & 0xFF) << 8)
+    | (results[0] & 0xFF);
+}