/*
 * Cisco router simulation platform.
 * Copyright (c) 2006 Christophe Fillot (cf@utc.fr)
 *
 * CRC functions.
 */

#ifndef __CRC_H__
#define __CRC_H__

#include <sys/types.h>
#include "utils.h"

extern m_uint16_t crc12_array[], crc16_array[];
extern m_uint32_t crc32_array[];

/* Compute a CRC-12 hash on a 32-bit integer */
static forced_inline m_uint32_t crc12_hash_u32 (m_uint32_t val)
{
    register m_uint32_t crc = 0;
    register int i;

    for (i = 0; i < 4; i++) {
        crc = (crc >> 8) ^ crc12_array[(crc ^ val) & 0xff];
        val >>= 8;
    }

    return (crc);
}

/* Compute a CRC-16 hash on a 32-bit integer */
static forced_inline m_uint32_t crc16_hash_u32 (m_uint32_t val)
{
    register m_uint32_t crc = 0;
    register int i;

    for (i = 0; i < 4; i++) {
        crc = (crc >> 8) ^ crc16_array[(crc ^ val) & 0xff];
        val >>= 8;
    }

    return (crc);
}

/* Compute a CRC-32 on the specified block */
static forced_inline m_uint32_t crc32_compute (m_uint32_t crc_accum,
    m_uint8_t * ptr, int len)
{
    unsigned long c = crc_accum;
    int n;

    for (n = 0; n < len; n++) {
        c = crc32_array[(c ^ ptr[n]) & 0xff] ^ (c >> 8);
    }

    return (~c);
}

/* Initialize CRC algorithms */
void crc_init (void);

#endif