X-Git-Url: https://git.m6w6.name/?a=blobdiff_plain;f=lib%2Fmemcached_hash.c;h=33c1055bbfd70ffd60aa1e902739367136b08705;hb=5845b33395414c577e0d88cc13a011db55cffa02;hp=3e5eddfe55ab332285de495d14080eee7c220aaa;hpb=a95ca4ad9c0f9d23c8a83bd337acdecc221021ef;p=awesomized%2Flibmemcached

diff --git a/lib/memcached_hash.c b/lib/memcached_hash.c
index 3e5eddfe..33c1055b 100644
--- a/lib/memcached_hash.c
+++ b/lib/memcached_hash.c
@@ -1,12 +1,100 @@
 #include "common.h"
 
-unsigned int memcached_generate_hash(char *key, size_t key_length)
+/* Defines */
+static uint64_t FNV_64_INIT= 0xcbf29ce484222325LL;
+static uint64_t FNV_64_PRIME= 0x100000001b3LL;
+
+static uint32_t FNV_32_INIT= 2166136261UL;
+static uint32_t FNV_32_PRIME= 16777619;
+
+/* Prototypes */
+static uint64_t internal_generate_hash(char *key, size_t key_length);
+static uint64_t internal_generate_md5(char *key, size_t key_length);
+static uint64_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)
 {
-  unsigned int x = key_length;
-  char *ptr = key;
-  unsigned int value = 0;
+  uint64_t hash= 1; /* Just here to remove compile warning */
+  unsigned int x;
+
+  WATCHPOINT_ASSERT(ptr->number_of_hosts);
+
+  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;
+    }
+  }
 
-  while (x--) 
+  WATCHPOINT_ASSERT(hash);
+  if (ptr->flags & MEM_USE_KETAMA)
+  {
+    WATCHPOINT_ASSERT(0);
+    return 0;
+  }
+  else
+    return hash % ptr->number_of_hosts;
+}
+
+static uint64_t internal_generate_hash(char *key, size_t key_length)
+{
+  char *ptr= key;
+  uint64_t value= 0;
+
+  while (--key_length) 
   {
     value += *ptr++;
     value += (value << 10);
@@ -18,3 +106,27 @@ unsigned int memcached_generate_hash(char *key, size_t key_length)
 
   return value == 0 ? 1 : value;
 }
+
+static uint64_t internal_generate_md5(char *key, size_t key_length)
+{
+  unsigned char results[16];
+
+  md5_signature((unsigned char*)key, (unsigned int)key_length, results);
+
+  return (uint64_t)(( results[3] << 24 )
+                    | ( results[2] << 16 )
+                    | ( results[1] <<  8 )
+                    |   results[0] );
+}
+
+static uint64_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);
+}