/* -*- c++ -*- */
/*
 * Copyright 2005,2011,2012 Free Software Foundation, Inc.
 * 
 * This file is part of GNU Radio
 * 
 * GNU Radio 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 3, or (at your option)
 * any later version.
 * 
 * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

/*
 * See also ISO 3309 [ISO-3309] or ITU-T V.42 [ITU-V42] for a formal specification.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <gnuradio/digital/crc32.h>

namespace gr {
  namespace digital {

    // Automatically generated CRC function
    // polynomial: 0x104C11DB7
    unsigned int
    update_crc32(unsigned int crc, const unsigned char *data, size_t len)
    {
      static const unsigned int table[256] = {
	0x00000000U,0x04C11DB7U,0x09823B6EU,0x0D4326D9U,
	0x130476DCU,0x17C56B6BU,0x1A864DB2U,0x1E475005U,
	0x2608EDB8U,0x22C9F00FU,0x2F8AD6D6U,0x2B4BCB61U,
	0x350C9B64U,0x31CD86D3U,0x3C8EA00AU,0x384FBDBDU,
	0x4C11DB70U,0x48D0C6C7U,0x4593E01EU,0x4152FDA9U,
	0x5F15ADACU,0x5BD4B01BU,0x569796C2U,0x52568B75U,
	0x6A1936C8U,0x6ED82B7FU,0x639B0DA6U,0x675A1011U,
	0x791D4014U,0x7DDC5DA3U,0x709F7B7AU,0x745E66CDU,
	0x9823B6E0U,0x9CE2AB57U,0x91A18D8EU,0x95609039U,
	0x8B27C03CU,0x8FE6DD8BU,0x82A5FB52U,0x8664E6E5U,
	0xBE2B5B58U,0xBAEA46EFU,0xB7A96036U,0xB3687D81U,
	0xAD2F2D84U,0xA9EE3033U,0xA4AD16EAU,0xA06C0B5DU,
	0xD4326D90U,0xD0F37027U,0xDDB056FEU,0xD9714B49U,
	0xC7361B4CU,0xC3F706FBU,0xCEB42022U,0xCA753D95U,
	0xF23A8028U,0xF6FB9D9FU,0xFBB8BB46U,0xFF79A6F1U,
	0xE13EF6F4U,0xE5FFEB43U,0xE8BCCD9AU,0xEC7DD02DU,
	0x34867077U,0x30476DC0U,0x3D044B19U,0x39C556AEU,
	0x278206ABU,0x23431B1CU,0x2E003DC5U,0x2AC12072U,
	0x128E9DCFU,0x164F8078U,0x1B0CA6A1U,0x1FCDBB16U,
	0x018AEB13U,0x054BF6A4U,0x0808D07DU,0x0CC9CDCAU,
	0x7897AB07U,0x7C56B6B0U,0x71159069U,0x75D48DDEU,
	0x6B93DDDBU,0x6F52C06CU,0x6211E6B5U,0x66D0FB02U,
	0x5E9F46BFU,0x5A5E5B08U,0x571D7DD1U,0x53DC6066U,
	0x4D9B3063U,0x495A2DD4U,0x44190B0DU,0x40D816BAU,
	0xACA5C697U,0xA864DB20U,0xA527FDF9U,0xA1E6E04EU,
	0xBFA1B04BU,0xBB60ADFCU,0xB6238B25U,0xB2E29692U,
	0x8AAD2B2FU,0x8E6C3698U,0x832F1041U,0x87EE0DF6U,
	0x99A95DF3U,0x9D684044U,0x902B669DU,0x94EA7B2AU,
	0xE0B41DE7U,0xE4750050U,0xE9362689U,0xEDF73B3EU,
	0xF3B06B3BU,0xF771768CU,0xFA325055U,0xFEF34DE2U,
	0xC6BCF05FU,0xC27DEDE8U,0xCF3ECB31U,0xCBFFD686U,
	0xD5B88683U,0xD1799B34U,0xDC3ABDEDU,0xD8FBA05AU,
	0x690CE0EEU,0x6DCDFD59U,0x608EDB80U,0x644FC637U,
	0x7A089632U,0x7EC98B85U,0x738AAD5CU,0x774BB0EBU,
	0x4F040D56U,0x4BC510E1U,0x46863638U,0x42472B8FU,
	0x5C007B8AU,0x58C1663DU,0x558240E4U,0x51435D53U,
	0x251D3B9EU,0x21DC2629U,0x2C9F00F0U,0x285E1D47U,
	0x36194D42U,0x32D850F5U,0x3F9B762CU,0x3B5A6B9BU,
	0x0315D626U,0x07D4CB91U,0x0A97ED48U,0x0E56F0FFU,
	0x1011A0FAU,0x14D0BD4DU,0x19939B94U,0x1D528623U,
	0xF12F560EU,0xF5EE4BB9U,0xF8AD6D60U,0xFC6C70D7U,
	0xE22B20D2U,0xE6EA3D65U,0xEBA91BBCU,0xEF68060BU,
	0xD727BBB6U,0xD3E6A601U,0xDEA580D8U,0xDA649D6FU,
	0xC423CD6AU,0xC0E2D0DDU,0xCDA1F604U,0xC960EBB3U,
	0xBD3E8D7EU,0xB9FF90C9U,0xB4BCB610U,0xB07DABA7U,
	0xAE3AFBA2U,0xAAFBE615U,0xA7B8C0CCU,0xA379DD7BU,
	0x9B3660C6U,0x9FF77D71U,0x92B45BA8U,0x9675461FU,
	0x8832161AU,0x8CF30BADU,0x81B02D74U,0x857130C3U,
	0x5D8A9099U,0x594B8D2EU,0x5408ABF7U,0x50C9B640U,
	0x4E8EE645U,0x4A4FFBF2U,0x470CDD2BU,0x43CDC09CU,
	0x7B827D21U,0x7F436096U,0x7200464FU,0x76C15BF8U,
	0x68860BFDU,0x6C47164AU,0x61043093U,0x65C52D24U,
	0x119B4BE9U,0x155A565EU,0x18197087U,0x1CD86D30U,
	0x029F3D35U,0x065E2082U,0x0B1D065BU,0x0FDC1BECU,
	0x3793A651U,0x3352BBE6U,0x3E119D3FU,0x3AD08088U,
	0x2497D08DU,0x2056CD3AU,0x2D15EBE3U,0x29D4F654U,
	0xC5A92679U,0xC1683BCEU,0xCC2B1D17U,0xC8EA00A0U,
	0xD6AD50A5U,0xD26C4D12U,0xDF2F6BCBU,0xDBEE767CU,
	0xE3A1CBC1U,0xE760D676U,0xEA23F0AFU,0xEEE2ED18U,
	0xF0A5BD1DU,0xF464A0AAU,0xF9278673U,0xFDE69BC4U,
	0x89B8FD09U,0x8D79E0BEU,0x803AC667U,0x84FBDBD0U,
	0x9ABC8BD5U,0x9E7D9662U,0x933EB0BBU,0x97FFAD0CU,
	0xAFB010B1U,0xAB710D06U,0xA6322BDFU,0xA2F33668U,
	0xBCB4666DU,0xB8757BDAU,0xB5365D03U,0xB1F740B4U,
      };
  
      while(len > 0)
	{
	  crc = table[*data ^ ((crc >> 24) & 0xff)] ^ (crc << 8);
	  data++;
	  len--;
	}
      return crc;
    }

    unsigned int
    update_crc32(unsigned int crc, const std::string s)
    {
      return update_crc32(crc, (const unsigned char *)s.data(), s.size());
    }
    
    unsigned int
    crc32(const unsigned char *buf, size_t len)
    {
      return update_crc32(0xffffffff, buf, len) ^ 0xffffffff;
    }

    unsigned int
    crc32(const std::string s)
    {
      return crc32((const unsigned char *) s.data(), s.size());
    }

  } /* namespace digital */
} /* namespace gr */
