/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011  Cyan Worlds, Inc.

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 3 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, see <http://www.gnu.org/licenses/>.

You can contact Cyan Worlds, Inc. by email legal@cyan.com
 or by snail mail at:
      Cyan Worlds, Inc.
      14617 N Newport Hwy
      Mead, WA   99021

*==LICENSE==*/
#include "plChecksum.h"
#include "hsStream.h"

#include <cstring>

plChecksum::plChecksum(unsigned int bufsize, const char* buffer)
{
    unsigned int wndsz = GetWindowSize(),i = 0;
    fSum = 0;

    const char* bufferAbsEnd = buffer + bufsize;
    const char* bufferEnvenEnd = buffer + bufsize - (bufsize % wndsz);

    while (buffer < bufferEnvenEnd)
    {
        fSum += hsSWAP32(*((SumStorage*)buffer));
        buffer += wndsz;
    }

    SumStorage last = 0;
    while (buffer < bufferAbsEnd)
    {
        ((char*)&last)[i % wndsz] = *buffer;
        buffer++;
    }
    fSum+= hsSWAP32(last);
}

plMD5Checksum::plMD5Checksum( UInt32 size, UInt8 *buffer )
{
    fValid = false;
    Start();
    AddTo( size, buffer );
    Finish();
}

plMD5Checksum::plMD5Checksum()
{
    Clear();
}

plMD5Checksum::plMD5Checksum( const plMD5Checksum &rhs )
{
    memcpy( fChecksum, rhs.fChecksum, sizeof( fChecksum ) );
    fValid = rhs.fValid;
}

plMD5Checksum::plMD5Checksum( const char *fileName )
{
    CalcFromFile( fileName );
}

void plMD5Checksum::Clear()
{
    memset( fChecksum, 0, sizeof( fChecksum ) );
    fValid = false;
}

void    plMD5Checksum::CalcFromFile( const char *fileName)
{
    FILE *fp;
    fValid = false;
    
    if( fp = fopen(fileName, "rb" ) )
    {
        unsigned loadLen = 1024 * 1024;
        Start();

        UInt8 *buf = TRACKED_NEW UInt8[loadLen];
    
        while(int read = fread(buf, sizeof(UInt8), loadLen, fp))
            AddTo( read, buf );
        delete[] buf;

        Finish();
        fclose(fp);
    }
}

void    plMD5Checksum::Start( void )
{
    MD5_Init( &fContext );
    fValid = false;
}

void    plMD5Checksum::AddTo( UInt32 size, const UInt8 *buffer )
{
    MD5_Update( &fContext, buffer, size );
}

void    plMD5Checksum::Finish( void )
{
    MD5_Final( fChecksum, &fContext );
    fValid = true;
}

const char  *plMD5Checksum::GetAsHexString( void ) const
{
    const int   kHexStringSize = ( 2 * MD5_DIGEST_LENGTH ) + 1;
    static char tempString[ kHexStringSize ];

    int     i;
    char    *ptr;


    hsAssert( fValid, "Trying to get string version of invalid checksum" );

    for( i = 0, ptr = tempString; i < sizeof( fChecksum ); i++, ptr += 2 )
        sprintf( ptr, "%02x", fChecksum[ i ] );

    *ptr = 0;

    return tempString;
}

UInt8   plMD5Checksum::IHexCharToInt( char c ) const
{
    switch( c )
    {
        // yes, it's ugly, but it'll be fast :)
        case '0': return 0;
        case '1': return 1;
        case '2': return 2;
        case '3': return 3;
        case '4': return 4;
        case '5': return 5;
        case '6': return 6;
        case '7': return 7;
        case '8': return 8;
        case '9': return 9;

        case 'a': return 10;
        case 'b': return 11;
        case 'c': return 12;
        case 'd': return 13;
        case 'e': return 14;
        case 'f': return 15;

        case 'A': return 10;
        case 'B': return 11;
        case 'C': return 12;
        case 'D': return 13;
        case 'E': return 14;
        case 'F': return 15;
    }

    return 0xff;
}

void        plMD5Checksum::SetFromHexString( const char *string )
{
    const char  *ptr;
    int         i;


    hsAssert( strlen( string ) == 2 * MD5_DIGEST_LENGTH, "Invalid string in MD5Checksum Set()" );

    for( i = 0, ptr = string; i < sizeof( fChecksum ); i++, ptr += 2 )
        fChecksum[ i ] = ( IHexCharToInt( ptr[ 0 ] ) << 4 ) | IHexCharToInt( ptr[ 1 ] );

    fValid = true;
}

void plMD5Checksum::SetValue(UInt8* checksum)
{
    fValid = true;
    memcpy(fChecksum, checksum, sizeof(fChecksum));
}

bool    plMD5Checksum::operator==( const plMD5Checksum &rhs ) const
{
    return (fValid && rhs.fValid && memcmp(fChecksum, rhs.fChecksum, sizeof(fChecksum)) == 0);
}