git.m6w6.name Git - awesomized/libmemcached/blob - libmemcached/memcached_generate_hash_value.rst

   1 Generating hash values directly
   2 ===============================
   3
   4 Hash a key value
   5
   6 SYNOPSIS
   7 --------
   8
   9 #include <libmemcached/memcached.h>
  10     Compile and link with -lmemcachedutil -lmemcached
  11
  12 .. function:: uint32_t memcached_generate_hash_value (const char *key, size_t key_length, memcached_hash_t hash_algorithm)
  13
  14     :param key: the key to generate a hash of
  15     :param key_length: the length of the `key` without any terminating zero
  16     :param hash_algorithm: `memcached_hash_t`, the algorithm to use
  17     :returns: a 32 bit hash value
  18
  19 .. function:: uint32_t memcached_generate_hash (memcached_st *ptr, const char *key, size_t key_length)
  20
  21     :param ptr: pointer to an initialized `memcached_st` struct
  22     :param key: the key to generate a hash of
  23     :param key_length: the length of the `key` without any terminating zero
  24     :returns: a 32 bit hash value
  25
  26 .. c:type:: enum memcached_hash_t memcached_hash_t
  27
  28 .. enum:: memcached_hash_t
  29
  30     .. enumerator::  MEMCACHED_HASH_DEFAULT
  31
  32     .. enumerator::  MEMCACHED_HASH_MD5
  33
  34     .. enumerator::  MEMCACHED_HASH_CRC
  35
  36     .. enumerator::  MEMCACHED_HASH_FNV1_64
  37
  38     .. enumerator::  MEMCACHED_HASH_FNV1A_64
  39
  40     .. enumerator::  MEMCACHED_HASH_FNV1_32
  41
  42     .. enumerator::  MEMCACHED_HASH_FNV1A_32
  43
  44     .. enumerator::  MEMCACHED_HASH_HSIEH
  45
  46     .. enumerator::  MEMCACHED_HASH_MURMUR
  47
  48     .. enumerator::  MEMCACHED_HASH_JENKINS
  49
  50     .. enumerator::  MEMCACHED_HASH_MURMUR3
  51
  52     .. enumerator::  MEMCACHED_HASH_CUSTOM
  53
  54
  55
  56 DESCRIPTION
  57 -----------
  58
  59 :func:`memcached_generate_hash_value` allows you to hash a key using one of
  60 the hash functions defined in the library. This method is provided for
  61 the convenience of higher-level language bindings and is not necessary
  62 for normal memcache operations.
  63
  64 Support for `MEMCACHED_HASH_HSIEH` is a compile time option that is
  65 disabled by default. To enable tests for this hashing algorithm,
  66 configure and build libmemcached with the Hsieh hash enabled.
  67
  68 :func:`memcached_generate_hash` takes a :type:`memcached_st` structure
  69 and produces the hash value that would have been generated based on the
  70 defaults of :type:`memcached_st`.
  71
  72 As of version 0.36 all hash methods have been placed into the library
  73 libhashkit(3) which is linked with libmemcached(3). For more information please see its documentation.
  74
  75 RETURN VALUE
  76 ------------
  77
  78 A 32-bit integer which is the result of hashing the given key.
  79 For 64-bit hash algorithms, only the least-significant 32 bits are
  80 returned.
  81
  82 SEE ALSO
  83 --------
  84
  85 .. only:: man
  86
  87   :manpage:`memcached(1)` :manpage:`libmemcached(3)` :manpage:`memcached_strerror(3)`