plugins-wimax-crc_c.c

Intel的WIMAX代码,主要是mac层code

plugins/wimax/crc.c - Google Code Search这是 Google 取自 
      http://anonsvn.wireshark.org/wireshark/trunk 的 plugins/wimax/crc.c 缓存副本

      Google 和网页作者无关，不对网页的内容负责。



http://anonsvn.wireshark.org/wireshark/trunk/plugins/wimax/
          AUTHORS
COPYING
ChangeLog
Makefile.am
Makefile.common
Makefile.nmake
README.wimax
crc.c
crc.h
crc_data.c
mac_hd_generic_decoder.c
mac_hd_type1_decoder.c
mac_hd_type2_decoder.c
mac_mgmt_msg_decoder.c
moduleinfo.h
moduleinfo.nmake
msg_aas_beam.c
msg_aas_fbck.c
msg_arq.c
msg_clk_cmp.c
msg_dcd.c
msg_dlmap.c
msg_dreg.c
msg_dsa.c
msg_dsc.c
msg_dsd.c
msg_dsx_rvd.c
msg_fpc.c
msg_pkm.c
msg_pmc.c
msg_prc_lt_ctrl.c
msg_reg_req.c
msg_reg_rsp.c
msg_rep.c
msg_res_cmd.c
msg_rng_req.c
msg_rng_rsp.c
msg_sbc.c
msg_ucd.c
msg_ulmap.c
packet-wmx.c
plugin.rc.in
wimax_bits.h
wimax_cdma_code_decoder.c
wimax_compact_dlmap_ie_decoder.c
wimax_compact_ulmap_ie_decoder.c
wimax_fch_decoder.c
wimax_ffb_decoder.c
wimax_hack_decoder.c
wimax_harq_map_decoder.c
wimax_mac.h
wimax_pdu_decoder.c
wimax_phy_attributes_decoder.c
wimax_tlv.c
wimax_tlv.h
wimax_utils.c
wimax_utils.h
    /* crc.c
 * crc checksum generation and calculation functions: crc.c
 *
 * Copyright (c) 2007 by Intel Corporation.
 *
 * Author: Mike Harvey <[e-mail]>
 *
 * $Id$
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <[e-mail]>
 * Copyright 1999 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include "crc.h"

#define WMAX_MAC_CRC32_POLYNOMIAL 0x04c11db7L /* polynomial used in calculating the CRC-32 checksum */
#define CCITT_X25_CRC16_POLYNOMIAL 0x1021     /* polynomial used in calculating the CRC-16 checksum */
#define WMAX_MAC_CRC8_POLYNOMIAL  0x07	      /* polynomial used in calculating the CRC-8 checksum */
#define CRC32_INITIAL_VALUE       0xFFFFFFFF
#define CRC16_INITIAL_VALUE       0xFFFF

#ifndef STATIC_DATA
static guint8  crc8_table[256];
static guint32 crc32_table[256];

extern guint16 crc16_table[256];

/*
  void wimax_mac_gen_crc32_table(void)

  REQUIRES: The functions must be called only once to initialze CRC table

  DESCRIPTION:  Generate the table of CRC remainders
                for all possible bytes

  ARGS:

  RETURNS:

  SIDE EFFECTS:

*/
void wimax_mac_gen_crc32_table(void)
{
  guint32 index, bit;
  guint32 crc;

  /* little-endian (reflected) algorithm */
          for ( index = 0;  index < 256;  index++ )
	  {
		    crc = ( index << 24 );
			
		    for ( bit = 0;  bit < 8;  bit++ )
		    {
			      if ( crc & 0x80000000L )
			        crc = ( crc << 1 ) ^ WMAX_MAC_CRC32_POLYNOMIAL;
			      else
			        crc = ( crc << 1 );
		    }
			
		    crc32_table[index] = crc;
	  }
}

/*
  void wimax_mac_gen_crc8_table(void)

  REQUIRES: The functions must be called only once to initialze CRC table

  DESCRIPTION:  Generate the table of CRC remainders
                for all possible bytes

  ARGS:

  RETURNS:

  SIDE EFFECTS:

*/
void wimax_mac_gen_crc8_table(void)
{
  guint  index, bit;
  guint8 crc;

  for ( index = 0;  index < 256;  index++ )
  {
    crc = index;
    for ( bit = 0;  bit < 8;  bit++ )
    {
      if ( crc & 0x80 )
        crc = ( crc << 1 ) ^ WMAX_MAC_CRC8_POLYNOMIAL;
      else
        crc = ( crc << 1 );
    }
    crc8_table[index] = crc;
  }
}
#endif

/*

  guint32 wimax_mac_calc_crc32(guint8 *data, guint data_len)

  REQUIRES: wimax_mac_gen_crc32_table() must be called before

  DESCRIPTION: Calculate the 32-bit CRC from a given data block

  ARGS:  data - pointer to data
         data_len - length of data (in bytes)

  RETURNS:  calculated crc32

  SIDE EFFECTS:

*/
guint32 wimax_mac_calc_crc32(guint8 *data, guint data_len)
{
  guint32 crc=CRC32_INITIAL_VALUE;
  guint i, j;

  for ( j = 0;  j < data_len;  j++ )
  {
    i = ( (guint8)(crc>>24) ^ data[j] ) & 0xff;
    crc = ( crc<<8 ) ^ crc32_table[i];
  }
  return ~crc;
}

/*

  guint16 wimax_mac_calc_crc16(guint8 *data, guint data_len)

  REQUIRES: crc16_table[] in crc_data.c

  DESCRIPTION: Calculate the 16-bit CRC from a given data block

  ARGS:  data - pointer to data
         data_len - length of data (in bytes)

  RETURNS:  calculated crc16

  SIDE EFFECTS:

*/
guint16 wimax_mac_calc_crc16(guint8 *data, guint data_len)
{
  guint32 crc=CRC16_INITIAL_VALUE;
  guint j;

  for ( j = 0;  j < data_len;  j++ )
  {
    crc ^= data[j] << 8;
    crc = (crc << 8) ^ crc16_table[(crc & 0xff00) >> 8];
  }
  crc ^= 0xFFFF;	/* Invert the output. */
  crc &= 0xFFFF;
  return crc;
}

/*

  guint8 wimax_mac_calc_crc8(guint8 *data, guint data_len)

  REQUIRES: wimax_mac_gen_crc8_table() must be called before

  DESCRIPTION: Calculate the 8-bit CRC from a given data block

  ARGS:  data - pointer to data
         data_len - length of data (in bytes)

  RETURNS:  calculated crc8

  SIDE EFFECTS:

*/
guint8 wimax_mac_calc_crc8(guint8 *data, guint data_len)
{
  guint8 crc=0;
  guint i;

  for(i = 0; i < data_len; i++)
  {
    crc = crc8_table[data[i]^crc];
  }
  return crc;
}



      取自 
      http://anonsvn.wireshark.org/wireshark/trunk 的 plugins/wimax/crc.c - LGPL 
      - C