X-Git-Url: https://git.m6w6.name/?a=blobdiff_plain;f=lib%2Fmemcached_hash.c;h=60c88e3bfb9da057c91eaafd4221245732479ed6;hb=9caad97a2b8b11488b2ba3583922864ac3ccbb09;hp=4d0d6cf2e782c46db99f57d12365147ede179708;hpb=f580e35770a744c60cb92e1cd581944d9da72205;p=awesomized%2Flibmemcached

diff --git a/lib/memcached_hash.c b/lib/memcached_hash.c
index 4d0d6cf2..60c88e3b 100644
--- a/lib/memcached_hash.c
+++ b/lib/memcached_hash.c
@@ -1,39 +1,114 @@
 #include "common.h"
 
+/* 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 unsigned int internal_generate_hash(char *key, size_t key_length);
+static uint32_t 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_ketama_md5(char *key, size_t key_length);
 
 unsigned int memcached_generate_hash(memcached_st *ptr, char *key, size_t key_length)
 {
-  unsigned int return_value;
+  uint32_t hash= 1; /* Just here to remove compile warning */
+  unsigned int x;
 
-  if (ptr->flags & MEM_USE_MD5)
-  {
-    unsigned char results[16];
+  WATCHPOINT_ASSERT(ptr->number_of_hosts);
 
-    md5_signature((unsigned char*)key, (unsigned int)key_length, results);
+  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);
+    if (hash == 0)
+      hash= 1;
+    break;
+    /* FNV hash'es lifted from Dustin Sallings work */
+  case MEMCACHED_HASH_FNV1_64: 
+    {
+      /* Thanks to pierre@demartines.com for the pointer */
+      uint64_t temp_hash;
 
-    return_value= (unsigned int)(( results[3] << 24 )
-				 | ( results[2] << 16 )
-				 | ( results[1] <<  8 )
-				 |   results[0] );
+      temp_hash= FNV_64_INIT;
+      for (x= 0; x < key_length; x++) 
+      {
+        temp_hash *= FNV_64_PRIME;
+        temp_hash ^= key[x];
+      }
+      hash= (uint32_t)temp_hash;
+    }
+    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;
+    }
+    case MEMCACHED_HASH_HSIEH:
+    {
+      hash= hsieh_hash(key, key_length);
+      break;
+    }
   }
-  else
-    return_value= internal_generate_hash(key, key_length);
 
-  if (ptr->flags & MEM_USE_KETAMA)
+  WATCHPOINT_ASSERT(hash);
+
+  if (ptr->distribution == MEMCACHED_DISTRIBUTION_MODULA)
   {
-    assert(0);
-    return 0;
+    return hash % ptr->number_of_hosts;
   }
   else
-    return return_value % ptr->number_of_hosts;
+  {
+    unsigned int server_key;
+
+    server_key= hash % MEMCACHED_WHEEL_SIZE;
+
+    return ptr->wheel[server_key];
+  }
 }
 
-static unsigned int internal_generate_hash(char *key, size_t key_length)
+static uint32_t internal_generate_hash(char *key, size_t key_length)
 {
   char *ptr= key;
-  unsigned int value= 0;
+  uint32_t value= 0;
 
   while (--key_length) 
   {
@@ -47,3 +122,27 @@ static unsigned int internal_generate_hash(char *key, size_t key_length)
 
   return value == 0 ? 1 : value;
 }
+
+static uint32_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 (uint32_t)(( results[3] << 24 )
+                    | ( results[2] << 16 )
+                    | ( 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);
+}