view src/core/ngx_murmurhash.c @ 8509:5b0c229ba5fe quic

QUIC: fixed padding calculation. Sometimes, QUIC packets need to be of certain (or minimal) size. This is achieved by adding PADDING frames. It is possible, that adding padding will affect header size, thus forcing us to recalculate padding size once more.
author Vladimir Homutov <vl@nginx.com>
date Mon, 05 Jul 2021 13:17:10 +0300
parents f38647c651a8
children
line wrap: on
line source


/*
 * 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;
        /* fall through */
    case 2:
        h ^= data[1] << 8;
        /* fall through */
    case 1:
        h ^= data[0];
        h *= 0x5bd1e995;
    }

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

    return h;
}