// Copyright (C) 1999-2005 Open Source Telecom Corporation.
// Copyright (C) 2006-2010 David Sugar, Tycho Softworks.
//
// 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.
//
// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.
//
// This exception applies only to the code released under the name GNU
// Common C++.  If you copy code from other releases into a copy of GNU
// Common C++, as the General Public License permits, the exception does
// not apply to the code that you add in this way.  To avoid misleading
// anyone as to the status of such modified files, you must delete
// this exception notice from them.
//
// If you write modifications of your own for GNU Common C++, it is your choice
// whether to permit this exception to apply to your modifications.
// If you do not wish that, delete this exception notice.
//

#include <cc++/config.h>
#include <cc++/string.h>
#include <cc++/exception.h>
#include <cc++/thread.h>
#include <cc++/export.h>
#include <cc++/digest.h>

#include <cstdio>
#include <iomanip>

#ifdef  WIN32
#include <io.h>
#endif

#ifdef  CCXX_NAMESPACES
namespace ost {
using namespace std;
#endif

Digest::Digest() :
streambuf()
#ifdef  HAVE_OLD_IOSTREAM
,ostream()
#else
,ostream((streambuf *)this)
#endif
{
#ifdef  HAVE_OLD_IOSTREAM
    init((streambuf *)this);
#endif
    }

Digest::~Digest()
{
}

ChecksumDigest::ChecksumDigest() :
Digest()
{
    csum = 0;
}

int ChecksumDigest::overflow(int c)
{
    csum += c;
    return c;
}

unsigned ChecksumDigest::getDigest(unsigned char *buffer)
{
    *buffer = csum;
    return 1;
}

void ChecksumDigest::putDigest(const unsigned char *buffer, unsigned len)
{
    while(len--)
        csum += *(buffer++);
}

ostream &ChecksumDigest::strDigest(ostream &os)
{
    char buf[3];

    sprintf(buf, "%02x", csum);
    os << buf;
    return os;
}

CRC16Digest::CRC16Digest() : Digest()
{
    crc16 = 0;
}

CRC16Digest::CRC16Digest (const CRC16Digest &crc ) : Digest()
{
    crc16 = crc.crc16;
}

CRC16Digest& CRC16Digest::operator= ( const CRC16Digest &right )
{
    if ( this == &right ) return *this;
    crc16 = right.crc16;
    return *this;
}

int CRC16Digest::overflow ( int c )
{
    crc16 = ( unsigned char ) ( crc16 >> 8 ) | ( crc16 << 8 );
    crc16 ^= ( unsigned char ) ( c );
    crc16 ^= ( unsigned char ) ( crc16 & 0xff ) >> 4;
    crc16 ^= ( crc16 << 8 ) << 4;
    crc16 ^= ( ( crc16 & 0xff ) << 4 ) << 1;
    return c;
}

unsigned CRC16Digest::getDigest ( unsigned char *buffer )
{
    memcpy ( buffer, &crc16, sizeof(crc16) );
    return sizeof(crc16);
}

void CRC16Digest::putDigest ( const unsigned char *buffer, unsigned len )
{
    while (len--)
        overflow (*buffer++);
}

ostream &CRC16Digest::strDigest ( ostream &os )
{
    return os << std::setw(4) << std::setfill('0') << std::hex << (unsigned)crc16 << std::dec;
}


CRC32Digest::CRC32Digest() : Digest()
{
    initDigest();
    crc32 = 0;
}

CRC32Digest::CRC32Digest(const CRC32Digest &crc) : Digest()
{
    crc32 = crc.crc32;
    crc_reg = crc.crc_reg;
    register int32 i;
    for (i = 0; i < 256; i++) {
        crc_table[i] = crc.crc_table[i];
    }
}

void CRC32Digest::initDigest(void)
{
    // the generator polynomial used here is the same as Ethernet
    // x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1
    const uint32 POLYNOMIAL = 0x04C11DB7;

    // Initialize the accumulator to all ones
    crc_reg = 0xFFFFFFFF;

    // Initialize the lookup table
    register int32 i,j;
    register uint32 crc;

    for (i = 0; i < 256; i++) {
        crc = ( (uint32) i << 24 );
        for (j = 0; j < 8; j++) {
            if (crc & 0x80000000)
                crc = (crc << 1) ^ POLYNOMIAL;
            else
                crc <<= 1;
        }
        crc_table[i] = crc;
    }
}


unsigned char CRC32Digest::overflow(unsigned char octet)
{
    crc_reg = crc_table[((crc_reg >> 24) ^ octet) & 0xFF] ^ (crc_reg << 8);
    crc32 = ~crc_reg;

    return octet;
}

unsigned CRC32Digest::getDigest(unsigned char *buffer)
{
    memcpy(buffer, &crc32, sizeof(crc32));
    return sizeof(crc32);
}

void CRC32Digest::putDigest(const unsigned char *buffer, unsigned len)
{
    while(len--)
        overflow(*buffer++);
}

ostream& CRC32Digest::strDigest(ostream &os)
{
  return os << std::setw(8) << std::setfill('0') << std::hex << (unsigned)crc32 << std::dec;
}

CRC32Digest& CRC32Digest::operator= (const CRC32Digest &right)
{
    if ( this == &right ) return *this;
  crc32   = right.crc32;
    crc_reg = right.crc_reg;

    register int32 i;
    for (i = 0; i < 256; i++) {
        crc_table[i] = right.crc_table[i];
    }

    return *this;
}


#ifdef  CCXX_NAMESPACES
}
#endif