ucx: src/hash_key.c@69a83fad8a35 (annotated)

src/hash_key.c@69a83fad8a35 (annotated)

src/hash_key.c

Wed, 08 Jun 2022 21:33:31 +0200

author: Mike Becker <universe@uap-core.de>
date: Wed, 08 Jun 2022 21:33:31 +0200
changeset 563: 69a83fad8a35
child 603: c49104015a6b
permissions: -rw-r--r--

improve hash key handling

 /*
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
  *
  * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *   1. Redistributions of source code must retain the above copyright
  *      notice, this list of conditions and the following disclaimer.
  *
  *   2. Redistributions in binary form must reproduce the above copyright
  *      notice, this list of conditions and the following disclaimer in the
  *      documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include "cx/hash_key.h"
 #include <string.h>
 void cx_hash_murmur(CxHashKey *key) {
     size_t len = key->len;
     unsigned char const *data = key->data.cbytes;
     unsigned m = 0x5bd1e995;
     unsigned r = 24;
     unsigned h = 25 ^ len;
     unsigned i = 0;
     while (len >= 4) {
         unsigned k = data[i + 0] & 0xFF;
         k |= (data[i + 1] & 0xFF) << 8;
         k |= (data[i + 2] & 0xFF) << 16;
         k |= (data[i + 3] & 0xFF) << 24;
         k *= m;
         k ^= k >> r;
         k *= m;
         h *= m;
         h ^= k;
         i += 4;
         len -= 4;
     }
     switch (len) {
         case 3:
             h ^= (data[i + 2] & 0xFF) << 16;
                     __attribute__((__fallthrough__));
         case 2:
             h ^= (data[i + 1] & 0xFF) << 8;
                     __attribute__((__fallthrough__));
         case 1:
             h ^= (data[i + 0] & 0xFF);
             h *= m;
                     __attribute__((__fallthrough__));
         default:
             /* do nothing */;
     }
     h ^= h >> 13;
     h *= m;
     h ^= h >> 15;
     key->hash = h;
 }
 CxHashKey cx_hash_key_str(char const *str) {
     CxHashKey key;
     key.data.cstr = str;
     key.len = str == NULL ? 0 : (1 + strlen(str));
     cx_hash_murmur(&key);
     return key;
 }
 CxHashKey cx_hash_key_bytes(
         unsigned char const *bytes,
         size_t len
 ) {
     CxHashKey key;
     key.data.cbytes = bytes;
     key.len = len;
     cx_hash_murmur(&key);
     return key;
 }
 CxHashKey cx_hash_key(
         void *obj,
         size_t len
 ) {
     CxHashKey key;
     key.data.obj = obj;
     key.len = len;
     cx_hash_murmur(&key);
     return key;
 }

Mercurial > hg > ucx / annotate

src/hash_key.c@69a83fad8a35 (annotated)

src/hash_key.c