/*
 * Copyright (c) 2004-2006 Maxim Sobolev <sobomax@FreeBSD.org>
 * Copyright (c) 2006-2014 Sippy Software, Inc., http://www.sippysoft.com
 * 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 AUTHOR 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 AUTHOR 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 <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "rtpp_pearson.h"

void
rtpp_pearson_shuffle(struct rtpp_pearson *rpp)
{
    int i;
    uint8_t rval;

    memset(rpp->rand_table, '\0', sizeof(rpp->rand_table));
    for (i = 1; i < 256; i++) {
        do {
            rval = random() & 0xff;
        } while (rpp->rand_table[rval] != 0);
        rpp->rand_table[rval] = i;
    }
}

uint8_t
rtpp_pearson_hash8(struct rtpp_pearson *rpp, const char *bp, const char *ep)
{
    uint8_t res;

    for (res = rpp->rand_table[0]; bp[0] != '\0' && bp != ep; bp++) {
        res = rpp->rand_table[res ^ bp[0]];
    }
    return res;
}

uint8_t
rtpp_pearson_hash8b(struct rtpp_pearson *rpp, const uint8_t *bp, size_t blen)
{
    uint8_t res;
    const uint8_t *ep;

    ep = bp + blen;
    for (res = rpp->rand_table[0]; bp != ep; bp++) {
        res = rpp->rand_table[res ^ bp[0]];
    }
    return res;
}
