/* Copyright (c) <2009> <Newton Game Dynamics>
* 
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* 
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely
*/

#include "dContainersStdAfx.h"
#include "dCRC.h"


static unsigned randBits[] = 
{
	0x00000001, 0x2C11F801, 0xDFD8F60E, 0x6C8FA2B7, 
	0xB573754C, 0x1522DCDD, 0x21615D3A, 0xE1B307F3, 
	0x12AFA158, 0x53D18179, 0x70950126, 0x941702EF, 
	0x756FE824, 0x694801D5, 0x36DF4DD2, 0x63D80FAB, 
	0xB8AE95B0, 0x902439F1, 0x090C6F3E, 0x2B7C6A27, 
	0x8344B5FC, 0x67D3C5CD, 0x22F5516A, 0x2FB00E63, 
	0xFC761508, 0x87B00169, 0x27EBA056, 0x8CC0B85F, 
	0xE33D3ED4, 0x95DA08C5, 0x13E5C802, 0x9DD9E41B, 
	0xD4577F60, 0x3DD6B7E1, 0x096AF46E, 0x1A00CD97, 
	0x4B10E2AC, 0x22EAAABD, 0x683F119A, 0x62D070D3, 
	0xA8D034B8, 0xAA363D59, 0x58CECB86, 0x40F589CF, 
	0x4F630184, 0x38918BB5, 0xB85B8E32, 0x0A6A948B, 
	0x9A099510, 0x402871D1, 0x11E7859E, 0xEE73CD07, 
	0x4142FB5C, 0x39D68BAD, 0x0FE19DCA, 0xE35B2F43, 
	0x75590068, 0x66433549, 0x929182B6, 0x71EC773F, 
	0xBBAC3034, 0xF2BD8AA5, 0x5743A062, 0x5AB120FB, 
	0x5ABFD6C0, 0xDDD867C1, 0xDC3522CE, 0xD0EC6877, 
	0xE106000C, 0xB7C6689D, 0xED3FF5FA, 0xC75749B3, 
	0x126B7818, 0x1A75E939, 0x0546C5E6, 0x8A9C80AF, 
	0x48A3CAE4, 0x756D0595, 0x7060FE92, 0xA594896B, 
	0x12354470, 0x896599B1, 0xDAC6CBFE, 0xCB419FE7, 
	0x9C44F0BC, 0xAFA9418D, 0xB87D1A2A, 0x428BC023, 
	0x33229BC8, 0xC92D5929, 0xB1C19516, 0x0FBCA61F, 
	0xE594D194, 0x716EFC85, 0x0036A8C2, 0xD7BBCDDB, 
	0x16E4DE20, 0xD10F07A1, 0x68CF812E, 0x390A7357, 
	0x8BAACD6C, 0x2C2E167D, 0x3E7C0A5A, 0x167F9293, 
	0x3D596B78, 0x08888519, 0x9994F046, 0x0FC3E78F, 
	0x008A4444, 0x87526F75, 0xB0079EF2, 0x238DEE4B, 
	0xCA09A3D0, 0x4ED3B191, 0xFA42425E, 0x379DE2C7, 
	0x1EA2961C, 0x1FC3E76D, 0x90DFC68A, 0x0279C103, 
	0xF9AAE728, 0xF2666D09, 0xEF13D776, 0x92E944FF, 
	0x364F22F4, 0x37665E65, 0x05D6E122, 0x7131EABB, 
	0x479E9580, 0x98729781, 0x4BD20F8E, 0x1612EE37, 
	0xCB574ACC, 0x5499B45D, 0x360B4EBA, 0x33814B73, 
	0x43720ED8, 0x146610F9, 0x45514AA6, 0x0B23BE6F, 
	0x026E6DA4, 0xD1B9C955, 0x94676F52, 0xCE8EC32B, 
	0x165EB330, 0x2F6AB971, 0x92F1E8BE, 0xC54095A7, 
	0xBEB3EB7C, 0x5C9E7D4D, 0x5921A2EA, 0xB45D31E3, 
	0xB8C9E288, 0x5FE670E9, 0xC02049D6, 0xC42A53DF, 
	0x6F332454, 0x661BB045, 0x2B3C4982, 0xDF4B779B, 
	0xD7C4FCE0, 0x70FB1761, 0xADD4CDEE, 0x47BDD917, 
	0x8C63782C, 0x8181423D, 0xFA05C31A, 0xDD947453, 
	0x6A8D6238, 0x1A068CD9, 0x4413D506, 0x5374054F, 
	0xC5A84704, 0xB41B1335, 0x06986FB2, 0x4CCF080B, 
	0xF80C7290, 0x8622B151, 0x536DBF1E, 0x21E1B887, 
	0xDED0F0DC, 0xB4B1032D, 0x1D5AAF4A, 0xC56E12C3, 
	0x8C578DE8, 0xCBA564C9, 0xA67EEC36, 0x0837D2BF, 
	0x3D98D5B4, 0x1B06F225, 0xFF7EE1E2, 0x3640747B, 
	0x5E301440, 0x53A08741, 0x436FBC4E, 0xC9C333F7, 
	0x2727558C, 0x7F5CC01D, 0xFC83677A, 0xAFF10D33, 
	0x24836598, 0x3161F8B9, 0xDD748F66, 0x5B6CBC2F, 
	0xAD8FD064, 0x89EE4D15, 0xBBB2A012, 0xA086BCEB, 
	0x1BEAE1F0, 0x69F39931, 0x764DC57E, 0x17394B67, 
	0x4D51A63C, 0xF273790D, 0x35A2EBAA, 0x7EE463A3, 
	0xBC2BE948, 0x2B9B48A9, 0x2FC7BE96, 0x5FC9C19F, 
	0x3AD83714, 0x6FA02405, 0xDDB6AA42, 0xE648E15B, 
	0x1DB7DBA0, 0xF55AE721, 0x4D3ADAAE, 0xB3DAFED7, 
	0x5FFAE2EC, 0x96A42DFD, 0xFB9C3BDA, 0x21CF1613, 
	0x0F2C18F8, 0xAE705499, 0x650B79C6, 0x31C5E30F, 
	0x097D09C4, 0xAAAB76F5, 0x34CE0072, 0x27EDE1CB, 
	0xDAD20150, 0xADD57111, 0xC229FBDE, 0x8AFF4E47, 
	0x448E0B9C, 0x5C5DDEED, 0x4612580A, 0x05F82483, 
	0xBC1EF4A8, 0xB1C01C89, 0xF592C0F6, 0x6798207F, 
	0xEC494874, 0x795F45E5, 0xECFBA2A2, 0xBB9CBE3B, 
	0xF567104f, 0x47289407, 0x25683fa6, 0x2fde5836, 
};


// calculate a 32 bit crc of a string
unsigned dCRC (const char* const name, unsigned crc)
{
	if (!name) {
		return 0;
	}

	for (unsigned char *ptr = (unsigned char*)name; *ptr; ptr ++) {
		unsigned c = *ptr;
		unsigned val = randBits[((crc >> 24) ^ c) & 0xff];
		crc = (crc << 8) ^ val;
	}
	return crc;
}


unsigned dCRC (const void* const buffer, int size, unsigned crcAcc)
{
	unsigned char *ptr = (unsigned char*)buffer;

	for (int i = 0; i < size; i ++) {
		unsigned c = ptr[i];
		unsigned val = randBits[((crcAcc >> 24) ^ c) & 0xff];
		crcAcc = (crcAcc << 8) ^ val;
	}
	return crcAcc;
}