Merging Trond

[awesomized/libmemcached] / libmemcached / memcached_hash.c

diff --git a/libmemcached/memcached_hash.c b/libmemcached/memcached_hash.c
index f365cc0ee6815b817e3304573b316a0d3f098144..e6747db5f7b2de3ba64ae67a658c9e25a60ebba6 100644 (file)
--- a/libmemcached/memcached_hash.c
+++ b/libmemcached/memcached_hash.c
@@ -1,5 +1,6 @@
 #include "common.h"
 
+
 /* Defines */
 static uint64_t FNV_64_INIT= 0xcbf29ce484222325LL;
 static uint64_t FNV_64_PRIME= 0x100000001b3LL;
@@ -8,21 +9,15 @@ static uint32_t FNV_32_INIT= 2166136261UL;
 static uint32_t FNV_32_PRIME= 16777619;
 
 /* Prototypes */
-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);
+static uint32_t internal_generate_hash(const char *key, size_t key_length);
+static uint32_t internal_generate_md5(const char *key, size_t key_length);
 
-unsigned int memcached_generate_hash(memcached_st *ptr, char *key, size_t key_length)
+uint32_t memcached_generate_hash_value(const char *key, size_t key_length, memcached_hash hash_algorithm)
 {
   uint32_t hash= 1; /* Just here to remove compile warning */
-  unsigned int x;
-
-  WATCHPOINT_ASSERT(ptr->number_of_hosts);
+  uint32_t x= 0;
 
-  if (ptr->number_of_hosts == 1)
-    return 0;
-
-  switch (ptr->hash)
+  switch (hash_algorithm)
   {
   case MEMCACHED_HASH_DEFAULT:
     hash= internal_generate_hash(key, key_length);
@@ -80,14 +75,11 @@ unsigned int memcached_generate_hash(memcached_st *ptr, char *key, size_t key_le
       }
     }
     break;
-    case MEMCACHED_HASH_KETAMA: 
-    {
-      hash= internal_generate_ketama_md5(key, key_length);
-      break;
-    }
     case MEMCACHED_HASH_HSIEH:
     {
+#ifdef HAVE_HSIEH_HASH
       hash= hsieh_hash(key, key_length);
+#endif
       break;
     }
     case MEMCACHED_HASH_MURMUR:
@@ -95,30 +87,116 @@ unsigned int memcached_generate_hash(memcached_st *ptr, char *key, size_t key_le
       hash= murmur_hash(key, key_length);
       break;
     }
+    case MEMCACHED_HASH_JENKINS:
+    {
+      hash=jenkins_hash(key, key_length, 13);
+      break;
+    }
   }
+  return hash;
+}
+
+uint32_t generate_hash(memcached_st *ptr, const char *key, size_t key_length)
+{
+  uint32_t hash= 1; /* Just here to remove compile warning */
+
+
+  WATCHPOINT_ASSERT(ptr->number_of_hosts);
+
+  if (ptr->number_of_hosts == 1)
+    return 0;
 
+  hash= memcached_generate_hash_value(key, key_length, ptr->hash);
   WATCHPOINT_ASSERT(hash);
+  return hash;
+}
 
-  if (ptr->distribution == MEMCACHED_DISTRIBUTION_MODULA)
+static uint32_t dispatch_host(memcached_st *ptr, uint32_t hash)
+{
+  switch (ptr->distribution) 
   {
+  case MEMCACHED_DISTRIBUTION_CONSISTENT:
+  case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
+    {
+      uint32_t num= ptr->continuum_points_counter;
+      WATCHPOINT_ASSERT(ptr->continuum);
+
+      hash= hash;
+      memcached_continuum_item_st *begin, *end, *left, *right, *middle;
+      begin= left= ptr->continuum;
+      end= right= ptr->continuum + num;
+
+      while (left < right)
+      {
+        middle= left + (right - left) / 2;
+        if (middle->value < hash)
+          left= middle + 1;
+        else
+          right= middle;
+      }
+      if (right == end)
+        right= begin;
+      return right->index;
+    } 
+    break;
+  case MEMCACHED_DISTRIBUTION_MODULA:
+    return hash % ptr->number_of_hosts;
+  case MEMCACHED_DISTRIBUTION_RANDOM:
+    return random() % ptr->number_of_hosts;
+  default:
+    WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
     return hash % ptr->number_of_hosts;
   }
+
+  /* NOTREACHED */
+}
+
+/* 
+  One day make this public, and have it return the actual memcached_server_st 
+  to the calling application.
+*/
+uint32_t memcached_generate_hash(memcached_st *ptr, const char *key, size_t key_length)
+{
+  uint32_t hash= 1; /* Just here to remove compile warning */
+
+  WATCHPOINT_ASSERT(ptr->number_of_hosts);
+
+  if (ptr->number_of_hosts == 1)
+    return 0;
+
+  if (ptr->flags & MEM_HASH_WITH_PREFIX_KEY)
+  {
+    int temp_len= ptr->prefix_key_length + key_length;
+    char *temp= (char *)malloc(temp_len);
+    strncpy(temp, ptr->prefix_key, ptr->prefix_key_length);
+    strncpy(temp + ptr->prefix_key_length, key, key_length);
+    hash= generate_hash(ptr, temp, temp_len);
+    free(temp);
+  }
   else
   {
-    unsigned int server_key;
+    hash= generate_hash(ptr, key, key_length);
+  }
 
-    server_key= hash % MEMCACHED_WHEEL_SIZE;
+  WATCHPOINT_ASSERT(hash);
 
-    return ptr->wheel[server_key];
+  if (memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS) && ptr->next_distribution_rebuild) {
+    struct timeval now;
+
+    if (gettimeofday(&now, NULL) == 0 &&
+        now.tv_sec > ptr->next_distribution_rebuild)
+      run_distribution(ptr);
   }
+
+  return dispatch_host(ptr, hash);
 }
 
-static uint32_t internal_generate_hash(char *key, size_t key_length)
+static uint32_t internal_generate_hash(const char *key, size_t key_length)
 {
-  char *ptr= key;
+  const char *ptr= key;
   uint32_t value= 0;
 
-  while (--key_length) 
+  while (key_length--) 
   {
     value += *ptr++;
     value += (value << 10);
@@ -131,19 +209,7 @@ static uint32_t 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)
+static uint32_t internal_generate_md5(const char *key, size_t key_length)
 {
   unsigned char results[16];