/*
crclib.c - generate crc stuff
Copyright (C) 2007 Uncle Mike

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.
*/

#include "crclib.h"
#include "crtlib.h"
#include <string.h>
#include <stdlib.h>

#define NUM_BYTES		256
#define CRC32_INIT_VALUE	0xFFFFFFFFUL
#define CRC32_XOR_VALUE	0xFFFFFFFFUL

static const uint32_t crc32table[NUM_BYTES] =
{
0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};

void GAME_EXPORT CRC32_Init( uint32_t *pulCRC )
{
	*pulCRC = CRC32_INIT_VALUE;
}

uint32_t GAME_EXPORT CRC32_Final( uint32_t pulCRC )
{
	return pulCRC ^ CRC32_XOR_VALUE;
}

void GAME_EXPORT CRC32_ProcessByte( uint32_t *pulCRC, byte ch )
{
	uint32_t	ulCrc = *pulCRC;

	*pulCRC = crc32table[((byte)ulCrc ^ ch)] ^ (ulCrc >> 8);
}

void GAME_EXPORT CRC32_ProcessBuffer( uint32_t *pulCRC, const void *pBuffer, int nBuffer )
{
	uint32_t	ulCrc = *pulCRC, tmp;
	byte	*pb = (byte *)pBuffer;

	while( nBuffer >= sizeof( uint64_t ))
	{
		memcpy( &tmp, pb, sizeof( tmp ));
		ulCrc ^= LittleLong( tmp );
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		memcpy( &tmp, pb + sizeof( tmp ), sizeof( tmp ));
		ulCrc ^= LittleLong( tmp );
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		nBuffer -= sizeof( uint64_t );
		pb += sizeof( uint64_t );
	}

	if( nBuffer & sizeof( uint32_t ))
	{
		memcpy( &tmp, pb, sizeof( tmp ));
		ulCrc ^= LittleLong( tmp );
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		ulCrc  = crc32table[(byte)ulCrc] ^ (ulCrc >> 8);
		nBuffer -= sizeof( uint32_t );
		pb += sizeof( uint32_t );
	}

	while( nBuffer-- )
	{
		ulCrc  = crc32table[((byte)ulCrc ^ *pb++)] ^ (ulCrc >> 8);
	}

	*pulCRC = ulCrc;
}

/*
====================
CRC32_BlockSequence

For proxy protecting
====================
*/
byte CRC32_BlockSequence( byte *base, int length, int sequence )
{
	uint32_t	CRC;
	char	*ptr;
	char	buffer[64];

	if( sequence < 0 ) sequence = abs( sequence );
	ptr = (char *)crc32table + (sequence % 0x3FC);

	if( length > 60 ) length = 60;
	memcpy( buffer, base, length );

	buffer[length+0] = ptr[0];
	buffer[length+1] = ptr[1];
	buffer[length+2] = ptr[2];
	buffer[length+3] = ptr[3];

	length += 4;

	CRC32_Init( &CRC );
	CRC32_ProcessBuffer( &CRC, buffer, length );
	CRC = CRC32_Final( CRC );

	return (byte)CRC;
}

void MD5Transform( uint buf[4], const uint in[16] );

/*
==================
MD5Init

Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious initialization constants.
==================
*/
void MD5Init( MD5Context_t *ctx )
{
	ctx->buf[0] = 0x67452301;
	ctx->buf[1] = 0xefcdab89;
	ctx->buf[2] = 0x98badcfe;
	ctx->buf[3] = 0x10325476;

	ctx->bits[0] = 0;
	ctx->bits[1] = 0;
}

/*
===================
MD5Update

Update context to reflect the concatenation of another buffer full of bytes.
===================
*/
void MD5Update( MD5Context_t *ctx, const byte *buf, uint len )
{
	uint	t;

	// update bitcount
	t = ctx->bits[0];

	if(( ctx->bits[0] = t + ((uint) len << 3 )) < t )
		ctx->bits[1]++;	// carry from low to high
	ctx->bits[1] += len >> 29;

	t = (t >> 3) & 0x3f;	// bytes already in shsInfo->data

	// handle any leading odd-sized chunks
	if( t )
	{
		byte	*p = (byte *)ctx->in + t;

		t = 64 - t;
		if( len < t )
		{
			memcpy( p, buf, len );
			return;
		}

		memcpy( p, buf, t );
		MD5Transform( ctx->buf, ctx->in );
		buf += t;
		len -= t;
	}

	// process data in 64-byte chunks
	while( len >= 64 )
	{
		memcpy( ctx->in, buf, 64 );
		MD5Transform( ctx->buf, ctx->in );
		buf += 64;
		len -= 64;
	}

	// handle any remaining bytes of data.
	memcpy( ctx->in, buf, len );
}

/*
===============
MD5Final

Final wrapup - pad to 64-byte boundary with the bit pattern
1 0* (64-bit count of bits processed, MSB-first)
===============
*/
void MD5Final( byte digest[16], MD5Context_t *ctx )
{
	uint	count;
	byte	*p;

	// compute number of bytes mod 64
	count = ( ctx->bits[0] >> 3 ) & 0x3F;

	// set the first char of padding to 0x80.
	// this is safe since there is always at least one byte free
	p = (byte*)ctx->in + count;
	*p++ = 0x80;

	// bytes of padding needed to make 64 bytes
	count = 64 - 1 - count;

	// pad out to 56 mod 64
	if( count < 8 )
	{

		// two lots of padding: pad the first block to 64 bytes
		memset( p, 0, count );
		MD5Transform( ctx->buf, ctx->in );

		// now fill the next block with 56 bytes
		memset( ctx->in, 0, 56 );
	}
	else
	{
		// pad block to 56 bytes
		memset( p, 0, count - 8 );
	}

	// append length in bits and transform
	ctx->in[14] = ctx->bits[0];
	ctx->in[15] = ctx->bits[1];

	MD5Transform( ctx->buf, ctx->in );
	memcpy( digest, ctx->buf, 16 );
	memset( ctx, 0, sizeof( *ctx ));	// in case it's sensitive
}

// The four core functions
#define F1( x, y, z ) ( z ^ ( x & ( y ^ z )))
#define F2( x, y, z ) F1( z, x, y )
#define F3( x, y, z ) ( x ^ y ^ z )
#define F4( x, y, z ) ( y ^ ( x | ~z ))

// this is the central step in the MD5 algorithm.
#define MD5STEP( f, w, x, y, z, data, s )	( w += f( x, y, z ) + data,  w = w << s|w >> (32 - s), w += x )

/*
=================
MD5Transform

The core of the MD5 algorithm, this alters an existing MD5 hash to
reflect the addition of 16 longwords of new data.  MD5Update blocks
the data and converts bytes into longwords for this routine.
=================
*/
void MD5Transform( uint buf[4], const uint in[16] )
{
	register uint	a, b, c, d;

	a = buf[0];
	b = buf[1];
	c = buf[2];
	d = buf[3];

	MD5STEP( F1, a, b, c, d, in[0] + 0xd76aa478, 7 );
	MD5STEP( F1, d, a, b, c, in[1] + 0xe8c7b756, 12 );
	MD5STEP( F1, c, d, a, b, in[2] + 0x242070db, 17 );
	MD5STEP( F1, b, c, d, a, in[3] + 0xc1bdceee, 22 );
	MD5STEP( F1, a, b, c, d, in[4] + 0xf57c0faf, 7 );
	MD5STEP( F1, d, a, b, c, in[5] + 0x4787c62a, 12 );
	MD5STEP( F1, c, d, a, b, in[6] + 0xa8304613, 17 );
	MD5STEP( F1, b, c, d, a, in[7] + 0xfd469501, 22 );
	MD5STEP( F1, a, b, c, d, in[8] + 0x698098d8, 7 );
	MD5STEP( F1, d, a, b, c, in[9] + 0x8b44f7af, 12 );
	MD5STEP( F1, c, d, a, b, in[10] + 0xffff5bb1, 17 );
	MD5STEP( F1, b, c, d, a, in[11] + 0x895cd7be, 22 );
	MD5STEP( F1, a, b, c, d, in[12] + 0x6b901122, 7 );
	MD5STEP( F1, d, a, b, c, in[13] + 0xfd987193, 12 );
	MD5STEP( F1, c, d, a, b, in[14] + 0xa679438e, 17 );
	MD5STEP( F1, b, c, d, a, in[15] + 0x49b40821, 22 );

	MD5STEP( F2, a, b, c, d, in[1] + 0xf61e2562, 5 );
	MD5STEP( F2, d, a, b, c, in[6] + 0xc040b340, 9 );
	MD5STEP( F2, c, d, a, b, in[11] + 0x265e5a51, 14 );
	MD5STEP( F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20 );
	MD5STEP( F2, a, b, c, d, in[5] + 0xd62f105d, 5 );
	MD5STEP( F2, d, a, b, c, in[10] + 0x02441453, 9 );
	MD5STEP( F2, c, d, a, b, in[15] + 0xd8a1e681, 14 );
	MD5STEP( F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20 );
	MD5STEP( F2, a, b, c, d, in[9] + 0x21e1cde6, 5 );
	MD5STEP( F2, d, a, b, c, in[14] + 0xc33707d6, 9 );
	MD5STEP( F2, c, d, a, b, in[3] + 0xf4d50d87, 14 );
	MD5STEP( F2, b, c, d, a, in[8] + 0x455a14ed, 20 );
	MD5STEP( F2, a, b, c, d, in[13] + 0xa9e3e905, 5 );
	MD5STEP( F2, d, a, b, c, in[2] + 0xfcefa3f8, 9 );
	MD5STEP( F2, c, d, a, b, in[7] + 0x676f02d9, 14 );
	MD5STEP( F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20 );

	MD5STEP( F3, a, b, c, d, in[5] + 0xfffa3942, 4 );
	MD5STEP( F3, d, a, b, c, in[8] + 0x8771f681, 11 );
	MD5STEP( F3, c, d, a, b, in[11] + 0x6d9d6122, 16 );
	MD5STEP( F3, b, c, d, a, in[14] + 0xfde5380c, 23 );
	MD5STEP( F3, a, b, c, d, in[1] + 0xa4beea44, 4 );
	MD5STEP( F3, d, a, b, c, in[4] + 0x4bdecfa9, 11 );
	MD5STEP( F3, c, d, a, b, in[7] + 0xf6bb4b60, 16 );
	MD5STEP( F3, b, c, d, a, in[10] + 0xbebfbc70, 23 );
	MD5STEP( F3, a, b, c, d, in[13] + 0x289b7ec6, 4 );
	MD5STEP( F3, d, a, b, c, in[0] + 0xeaa127fa, 11 );
	MD5STEP( F3, c, d, a, b, in[3] + 0xd4ef3085, 16 );
	MD5STEP( F3, b, c, d, a, in[6] + 0x04881d05, 23 );
	MD5STEP( F3, a, b, c, d, in[9] + 0xd9d4d039, 4 );
	MD5STEP( F3, d, a, b, c, in[12] + 0xe6db99e5, 11 );
	MD5STEP( F3, c, d, a, b, in[15] + 0x1fa27cf8, 16 );
	MD5STEP( F3, b, c, d, a, in[2] + 0xc4ac5665, 23 );

	MD5STEP( F4, a, b, c, d, in[0] + 0xf4292244, 6 );
	MD5STEP( F4, d, a, b, c, in[7] + 0x432aff97, 10 );
	MD5STEP( F4, c, d, a, b, in[14] + 0xab9423a7, 15 );
	MD5STEP( F4, b, c, d, a, in[5] + 0xfc93a039, 21 );
	MD5STEP( F4, a, b, c, d, in[12] + 0x655b59c3, 6 );
	MD5STEP( F4, d, a, b, c, in[3] + 0x8f0ccc92, 10 );
	MD5STEP( F4, c, d, a, b, in[10] + 0xffeff47d, 15 );
	MD5STEP( F4, b, c, d, a, in[1] + 0x85845dd1, 21 );
	MD5STEP( F4, a, b, c, d, in[8] + 0x6fa87e4f, 6 );
	MD5STEP( F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10 );
	MD5STEP( F4, c, d, a, b, in[6] + 0xa3014314, 15 );
	MD5STEP( F4, b, c, d, a, in[13] + 0x4e0811a1, 21 );
	MD5STEP( F4, a, b, c, d, in[4] + 0xf7537e82, 6 );
	MD5STEP( F4, d, a, b, c, in[11] + 0xbd3af235, 10 );
	MD5STEP( F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15 );
	MD5STEP( F4, b, c, d, a, in[9] + 0xeb86d391, 21 );

	buf[0] += a;
	buf[1] += b;
	buf[2] += c;
	buf[3] += d;
}

/*
=================
MD5_Print

transform hash to hexadecimal printable symbols
=================
*/
char *MD5_Print( byte hash[16] )
{
	static char	szReturn[64];
	int		i;

	memset( szReturn, 0, 64 );

	for( i = 0; i < 16; i++ )
		COM_Hex2String( hash[i], &szReturn[i * 2] );

	return szReturn;
}

/*
=================
COM_HashKey

returns hash key for string
=================
*/
uint COM_HashKey( const char *string, uint hashSize )
{
	uint hashKey = 5381;
	unsigned char i;

	while(( i = *string++ ))
	{
		i = Q_tolower( i );
		hashKey = ( hashKey << 5 ) + hashKey + ( i & 0xDF );
	}

	return hashKey & ( hashSize - 1 );
}
