#include <MvdOfflineTBAnalysis_Topix4/PndCRCCalculator.h>
#include <vector>
#include <iostream>
#include <cmath>

ClassImp(PndCRCCalculator);

PndCRCCalculator::PndCRCCalculator() :
	fOrder(16), fPolynom(0x8005), fCRCXor(0x0000), fRefIn(0), fRefOut(0), fCRCInit_direct(0)
{
	fCRCMask = ((((unsigned long)1<<(fOrder-1))-1)<<1)|1;
	fCRCHighBit = (unsigned long)1<<(fOrder-1);

	GenerateCRCTable();
}

PndCRCCalculator::PndCRCCalculator(UInt_t order, ULong64_t polynom, ULong64_t CRCXor, UInt_t refIn, UInt_t refOut, UInt_t CRCInit_direct) :
	fOrder(order), fPolynom(polynom), fCRCXor(CRCXor), fRefIn(refIn), fRefOut(refOut), fCRCInit_direct(CRCInit_direct)
{
	fCRCMask = ((((unsigned long)1<<(fOrder-1))-1)<<1)|1;
	fCRCHighBit = (unsigned long)1<<(fOrder-1);

	GenerateCRCTable();
}


PndCRCCalculator::~PndCRCCalculator() {
	// TODO Auto-generated destructor stub
}

//std::vector<char> PndCRCCalculator::ConvertData(std::vector<ULong64_t> topixFrame)
//{
//	std::vector<char> topix_data;
//	for (int i = 1; i < topixFrame.size() - 1; i++) {
//		for (int j = 0; j < 8; j++) {
//			if (j == 0 or j == 1 or j == 2) {
//				topix_data.push_back(0x00);
//			} else {
//				topix_data.push_back((topixFrame[i] >> (7 - j) * 2 * 4) & 0xff);
//			}
//		}
//	}
//	return topix_data;
//}

ULong64_t PndCRCCalculator::CalculateCRCTableFast(std::vector<char> p, ULong64_t len) {

	// fast lookup table algorithm without augmented zero bytes, e.g. used in pkzip.
	// only usable with polynom orders of 8, 16, 24 or 32.

	ULong64_t crc = fCRCInit_direct;

	std::vector<char>::iterator it = p.begin();

	if (fRefIn) {
		crc = ReflectBitsStream(crc, fOrder);
	}

	if (!fRefIn) {
		while (len--) {
			crc = (crc << 8) ^ fCRCTab[((crc >> (fOrder - 8)) & 0xff) ^ (*it & 0xff)];
			it++;
		}
	} else {
		while (len--) {
			crc = (crc >> 8) ^ fCRCTab[(crc & 0xff) ^ (*it & 0xff)];
			it++;
		}
	}
	if (fRefOut ^ fRefIn) {
		crc = ReflectBitsStream(crc, fOrder);
	}
	crc ^= fCRCXor;
	crc &= fCRCMask;

	return (crc);
}

void PndCRCCalculator::GenerateCRCTable() {
  // make CRC lookup table used by table algorithms
	ULong64_t bit, crc;
	for (int i=0; i<256; i++) {
		crc=(ULong64_t)i;
		if (fRefIn)
		  {
		    crc=ReflectBitsStream(crc, 8);
		  }
		crc<<= fOrder-8;

		for (int j=0; j<8; j++)
		  {
			bit = crc & fCRCHighBit;
			crc<<= 1;
			if (bit)
			  {
			    crc^= fPolynom;
			  }
		  }
		if (fRefIn)
		  {
		    crc = ReflectBitsStream(crc, fOrder);
		  }
		crc&= fCRCMask;
		fCRCTab[i]= crc;
	}
}

void PndCRCCalculator::PrintCRCTable()
{
	for (int i = 0; i < 16; i++){
		for (int j = 0; j < 16; j++){
			std::cout << std::hex << fCRCTab[i*16 + j] << " ";
		}
		std::cout << std::endl;
	}
}

ULong64_t PndCRCCalculator::ReflectBitsStream(ULong64_t crc, int bitnum) {

	// reflects the lower 'bitnum' bits of 'crc'

	ULong64_t i, j=1, crcout=0;

	for (i=(ULong64_t)1<<(bitnum-1); i; i>>=1)
	  {
		if (crc & i)
		  {
		    crcout|=j;
		  }
		j<<= 1;
	  }
	return (crcout);
}