/* -*- 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 */
