From: Brian Aker <brian@tangent.org>
Date: Tue, 30 Oct 2007 18:31:25 +0000 (-0700)
Subject: Adding support for CRC Hashing
X-Git-Tag: 0.8~11
X-Git-Url: https://git.m6w6.name/?a=commitdiff_plain;h=ffe371b7498a26133a892591c7dc56d3e6212d10;p=m6w6%2Flibmemcached

Adding support for CRC Hashing
---

diff --git a/ChangeLog b/ChangeLog
index f0f7805f..a18c7851 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+0.8
+  * Adding support for CRC hash method 
+
 0.7 Tue Oct 30 09:24:05 PDT 2007
   * Poved to poll() from select()
   * Fixes in internal string class for allocation of large numbers of
diff --git a/configure.in b/configure.in
index adbfd5dd..241212ee 100644
--- a/configure.in
+++ b/configure.in
@@ -1,7 +1,7 @@
 AC_INIT(src/memcat.c)
 AC_CONFIG_AUX_DIR(config)
 AM_CONFIG_HEADER(include/libmemcached_config.h)
-AM_INIT_AUTOMAKE("libmemcached", 0.7)
+AM_INIT_AUTOMAKE("libmemcached", 0.8)
 
 AC_PROG_CC
 AC_PROG_LIBTOOL
diff --git a/include/memcached.h b/include/memcached.h
index 2cdc34d0..4cff494e 100644
--- a/include/memcached.h
+++ b/include/memcached.h
@@ -65,6 +65,7 @@ typedef enum {
   MEMCACHED_BEHAVIOR_NO_BLOCK,
   MEMCACHED_BEHAVIOR_TCP_NODELAY,
   MEMCACHED_BEHAVIOR_MD5_HASHING,
+  MEMCACHED_BEHAVIOR_CRC_HASHING,
   MEMCACHED_BEHAVIOR_KETAMA,
   MEMCACHED_BEHAVIOR_SOCKET_SEND_SIZE,
   MEMCACHED_BEHAVIOR_SOCKET_RECV_SIZE,
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 2f115bca..46534a5a 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -25,7 +25,8 @@ noinst_HEADERS = libmemcached_probes.h \
                  common.h
 
 lib_LTLIBRARIES = libmemcached.la
-libmemcached_la_SOURCES = memcached.c \
+libmemcached_la_SOURCES = crc.c \
+			  memcached.c \
 			  memcached_auto.c \
 			  memcached_behavior.c \
 			  memcached_connect.c \
diff --git a/lib/common.h b/lib/common.h
index 1f6f678e..ab5f9385 100644
--- a/lib/common.h
+++ b/lib/common.h
@@ -40,9 +40,14 @@ typedef enum {
   MEM_REUSE_MEMORY= (1 << 2),
   MEM_USE_MD5= (1 << 3),
   MEM_USE_KETAMA= (1 << 4),
+  MEM_USE_CRC= (1 << 5),
 } memcached_flags;
 
+/* Hashing algo */
 void md5_signature(unsigned char *key, unsigned int length, unsigned char *result);
+uint32_t hash_crc32(const char *data,
+                    size_t data_len);
+
 memcached_return memcached_connect(memcached_st *ptr, unsigned int server_key);
 memcached_return memcached_response(memcached_st *ptr, 
                                     char *buffer, size_t buffer_length,
diff --git a/lib/crc.c b/lib/crc.c
new file mode 100644
index 00000000..ec7e0d44
--- /dev/null
+++ b/lib/crc.c
@@ -0,0 +1,87 @@
+/* The crc32 functions and data was originally written by Spencer
+ * Garrett <srg@quick.com> and was gleaned from the PostgreSQL source
+ * tree via the files contrib/ltree/crc32.[ch] and from FreeBSD at
+ * src/usr.bin/cksum/crc32.c.
+ */
+
+#include "common.h"
+
+static const uint32_t crc32tab[256] = {
+  0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
+  0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
+  0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+  0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
+  0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
+  0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+  0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
+  0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
+  0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+  0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+  0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
+  0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+  0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
+  0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
+  0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+  0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
+  0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
+  0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+  0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
+  0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+  0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+  0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
+  0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
+  0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+  0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
+  0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
+  0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+  0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
+  0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
+  0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+  0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
+  0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
+  0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+  0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
+  0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
+  0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+  0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
+  0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
+  0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+  0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+  0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
+  0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+  0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
+  0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
+  0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+  0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
+  0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
+  0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+  0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
+  0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+  0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+  0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
+  0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
+  0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+  0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
+  0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
+  0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+  0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
+  0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
+  0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+  0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
+  0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
+  0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+  0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d,
+};
+
+
+uint32_t hash_crc32(const char *data, size_t data_len)
+{
+  uint32_t x;
+  uint32_t crc;
+  crc = ~0;
+
+  for (x = 0; x < data_len; x++)
+    crc = (crc >> 8) ^ crc32tab[(crc ^ (data[x])) & 0xff];
+
+  return ~crc;
+}
diff --git a/lib/memcached_behavior.c b/lib/memcached_behavior.c
index 319c3fa3..783d411b 100644
--- a/lib/memcached_behavior.c
+++ b/lib/memcached_behavior.c
@@ -35,6 +35,9 @@ memcached_return memcached_behavior_set(memcached_st *ptr,
   case MEMCACHED_BEHAVIOR_MD5_HASHING:
     set_behavior_flag(ptr, MEM_USE_MD5, data);
     break;
+  case MEMCACHED_BEHAVIOR_CRC_HASHING:
+    set_behavior_flag(ptr, MEM_USE_CRC, data);
+    break;
   case MEMCACHED_BEHAVIOR_KETAMA:
     set_behavior_flag(ptr, MEM_USE_KETAMA, data);
     break;
@@ -73,6 +76,9 @@ unsigned long long memcached_behavior_get(memcached_st *ptr,
   case MEMCACHED_BEHAVIOR_MD5_HASHING:
     temp_flag= MEM_USE_MD5;
     break;
+  case MEMCACHED_BEHAVIOR_CRC_HASHING:
+    temp_flag= MEM_USE_CRC;
+    break;
   case MEMCACHED_BEHAVIOR_KETAMA:
     temp_flag= MEM_USE_KETAMA;
     break;
diff --git a/lib/memcached_hash.c b/lib/memcached_hash.c
index 0e26fbbe..073b0c5d 100644
--- a/lib/memcached_hash.c
+++ b/lib/memcached_hash.c
@@ -2,22 +2,16 @@
 
 /* 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);
 
 unsigned int memcached_generate_hash(memcached_st *ptr, char *key, size_t key_length)
 {
-  unsigned int hash;
+  uint32_t hash;
 
   if (ptr->flags & MEM_USE_MD5)
-  {
-    unsigned char results[16];
-
-    md5_signature((unsigned char*)key, (unsigned int)key_length, results);
-
-    hash= (unsigned int)(( results[3] << 24 )
-				 | ( results[2] << 16 )
-				 | ( results[1] <<  8 )
-				 |   results[0] );
-  }
+    hash= internal_generate_md5(key, key_length);
+  else if (ptr->flags & MEM_USE_CRC)
+    hash= hash_crc32(key, key_length);
   else
     hash= internal_generate_hash(key, key_length);
 
@@ -30,7 +24,7 @@ unsigned int memcached_generate_hash(memcached_st *ptr, char *key, size_t key_le
     return hash % ptr->number_of_hosts;
 }
 
-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;
@@ -47,3 +41,15 @@ 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] );
+}
diff --git a/support/libmemcached.spec b/support/libmemcached.spec
index 40e10658..90873440 100644
--- a/support/libmemcached.spec
+++ b/support/libmemcached.spec
@@ -1,6 +1,6 @@
 Summary: memcached C library and command line tools
 Name: libmemcached
-Version: 0.7
+Version: 0.8
 Release: 1
 License: BSD
 Group: System Environment/Libraries
diff --git a/tests/test.c b/tests/test.c
index 5653271a..3945df8b 100644
--- a/tests/test.c
+++ b/tests/test.c
@@ -810,6 +810,11 @@ void pre_md5(memcached_st *memc)
   memcached_behavior_set(memc, MEMCACHED_BEHAVIOR_MD5_HASHING, NULL);
 }
 
+void pre_crc(memcached_st *memc)
+{
+  memcached_behavior_set(memc, MEMCACHED_BEHAVIOR_CRC_HASHING, NULL);
+}
+
 void pre_nodelay(memcached_st *memc)
 {
   memcached_behavior_set(memc, MEMCACHED_BEHAVIOR_NO_BLOCK, NULL);
@@ -917,6 +922,7 @@ int main(int argc, char *argv[])
     {"nonblock", pre_nonblock, 0, tests},
     {"nodelay", pre_nodelay, 0, tests},
     {"md5", pre_md5, 0, tests},
+    {"crc", pre_crc, 0, tests},
     {"string", 0, 0, string_tests},
     {"user", 0, 0, user_tests},
     {0, 0, 0, 0}