view src/core/ngx_murmurhash.c @ 4497:95ab6658654a

Fix of rbtree lookup on hash collisions. Previous code incorrectly assumed that nodes with identical keys are linked together. This might not be true after tree rebalance. Patch by Lanshun Zhou.
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 27 Feb 2012 22:15:39 +0000
parents 203eb026ec07
children f38647c651a8
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/*
 * Copyright (C) Austin Appleby
 */


#include <ngx_config.h>
#include <ngx_core.h>


uint32_t
ngx_murmur_hash2(u_char *data, size_t len)
{
    uint32_t  h, k;

    h = 0 ^ len;

    while (len >= 4) {
        k  = data[0];
        k |= data[1] << 8;
        k |= data[2] << 16;
        k |= data[3] << 24;

        k *= 0x5bd1e995;
        k ^= k >> 24;
        k *= 0x5bd1e995;

        h *= 0x5bd1e995;
        h ^= k;

        data += 4;
        len -= 4;
    }

    switch (len) {
    case 3:
        h ^= data[2] << 16;
    case 2:
        h ^= data[1] << 8;
    case 1:
        h ^= data[0];
        h *= 0x5bd1e995;
    }

    h ^= h >> 13;
    h *= 0x5bd1e995;
    h ^= h >> 15;

    return h;
}