Merge in conversion to C++.

[awesomized/libmemcached] / libhashkit / ketama.cc

diff --git a/libhashkit/ketama.cc b/libhashkit/ketama.cc
new file mode 100644 (file)
index 0000000..45052c2
--- /dev/null
+++ b/libhashkit/ketama.cc
@@ -0,0 +1,164 @@
+/* HashKit
+ * Copyright (C) 2006-2009 Brian Aker
+ * All rights reserved.
+ *
+ * Use and distribution licensed under the BSD license.  See
+ * the COPYING file in the parent directory for full text.
+ */
+
+#include <libhashkit/common.h>
+#include <math.h>
+
+#if 0
+static uint32_t ketama_server_hash(const char *key, unsigned int key_length, int alignment)
+{
+  unsigned char results[16];
+
+  md5_signature((unsigned char*)key, key_length, results);
+  return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
+    | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
+    | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
+    | (results[0 + alignment * 4] & 0xFF);
+}
+
+static int continuum_points_cmp(const void *t1, const void *t2)
+{
+  hashkit_continuum_point_st *ct1= (hashkit_continuum_point_st *)t1;
+  hashkit_continuum_point_st *ct2= (hashkit_continuum_point_st *)t2;
+
+  if (ct1->value == ct2->value)
+    return 0;
+  else if (ct1->value > ct2->value)
+    return 1;
+  else
+    return -1;
+}
+
+int update_continuum(hashkit_st *hashkit)
+{
+  uint32_t count;
+  uint32_t continuum_index= 0;
+  uint32_t value;
+  uint32_t points_index;
+  uint32_t points_count= 0;
+  uint32_t points_per_server;
+  uint32_t points_per_hash;
+  uint64_t total_weight= 0;
+  uint32_t live_servers;
+  uint8_t *context;
+
+  if (hashkit->active_fn != NULL || hashkit->weight_fn != NULL)
+  {
+    live_servers= 0;
+
+    for (count= 0, context= hashkit->list; count < hashkit->list_size;
+         count++, context+= hashkit->context_size)
+    {
+      if (hashkit->active_fn != NULL)
+      {
+        if (hashkit->active_fn(context))
+          live_servers++;
+        else
+          continue;
+      }
+
+      if (hashkit->weight_fn != NULL)
+        total_weight+= hashkit->weight_fn(context);
+    }
+  }
+
+  if (hashkit->active_fn == NULL)
+    live_servers= (uint32_t)hashkit->list_size;
+
+  if (live_servers == 0)
+    return 0;
+
+  if (hashkit->weight_fn == NULL)
+  {
+    points_per_server= HASHKIT_POINTS_PER_NODE;
+    points_per_hash= 1;
+  }
+  else
+  {
+    points_per_server= HASHKIT_POINTS_PER_NODE_WEIGHTED;
+    points_per_hash= 4;
+  }
+
+  if (live_servers > hashkit->continuum_count)
+  {
+    hashkit_continuum_point_st *new_continuum;
+
+    new_continuum= realloc(hashkit->continuum,
+                           sizeof(hashkit_continuum_point_st) *
+                           (live_servers + HASHKIT_CONTINUUM_ADDITION) *
+                           points_per_server);
+
+    if (new_continuum == NULL)
+      return ENOMEM;
+
+    hashkit->continuum= new_continuum;
+    hashkit->continuum_count= live_servers + HASHKIT_CONTINUUM_ADDITION;
+  }
+
+  for (count= 0, context= hashkit->list; count < hashkit->list_size;
+       count++, context+= hashkit->context_size)
+  {
+    if (hashkit->active_fn != NULL && hashkit->active_fn(context) == false)
+      continue;
+
+    if (hashkit->weight_fn != NULL)
+    {
+        float pct = (float)hashkit->weight_fn(context) / (float)total_weight;
+        points_per_server= (uint32_t) ((floorf((float) (pct * HASHKIT_POINTS_PER_NODE_WEIGHTED / 4 * (float)live_servers + 0.0000000001))) * 4);
+    }
+
+    for (points_index= 0;
+         points_index < points_per_server / points_per_hash;
+         points_index++)
+    {
+      char sort_host[HASHKIT_CONTINUUM_KEY_SIZE]= "";
+      size_t sort_host_length;
+
+      if (hashkit->continuum_key_fn == NULL)
+      {
+        sort_host_length= (size_t) snprintf(sort_host, HASHKIT_CONTINUUM_KEY_SIZE, "%u",
+                                            points_index);
+      }
+      else
+      {
+        sort_host_length= hashkit->continuum_key_fn(sort_host, HASHKIT_CONTINUUM_KEY_SIZE,
+                                                 points_index, context);
+      }
+
+      if (hashkit->weight_fn == NULL)
+      {
+        if (hashkit->continuum_hash_fn == NULL)
+          value= hashkit_default(sort_host, sort_host_length);
+        else
+          value= hashkit->continuum_hash_fn(sort_host, sort_host_length);
+
+        hashkit->continuum[continuum_index].index= count;
+        hashkit->continuum[continuum_index++].value= value;
+      }
+      else
+      {
+        unsigned int i;
+        for (i = 0; i < points_per_hash; i++)
+        {
+           value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
+           hashkit->continuum[continuum_index].index= count;
+           hashkit->continuum[continuum_index++].value= value;
+        }
+      }
+    }
+
+    points_count+= points_per_server;
+  }
+
+  hashkit->continuum_points_count= points_count;
+  qsort(hashkit->continuum, hashkit->continuum_points_count, sizeof(hashkit_continuum_point_st),
+        continuum_points_cmp);
+
+  return 0;
+}
+#endif