codecrypt/lib/bvector.cpp

#include "codecrypt.h"
using namespace ccr;

uint bvector::hamming_weight()
{
	uint r = 0;
	for (uint i = 0; i < size(); ++i) if ( (*this) [i]) ++r;
	return r;
}

void bvector::add (const bvector&a)
{
	if (a.size() > size() ) resize (a.size(), 0);
	for (uint i = 0; i < size(); ++i)
		item (i) = item (i) ^ a[i];
}

bool bvector::operator* (const bvector&a)
{
	bool r = 0;
	uint s = size(), i;
	if (s > a.size() ) s = a.size();
	for (i = 0; i < s; ++i) r ^= (item (i) &a[i]);
	return r;
}

bool bvector::zero() const
{
	for (uint i = 0; i < size(); ++i) if (item (i) ) return false;
	return true;
}

void bvector::to_poly (polynomial&r, gf2m&fld)
{
	r.clear();
	if (size() % fld.m) return; //impossible
	r.resize (size() / fld.m, 0);
	for (uint i = 0; i < size(); ++i)
		if (item (i) ) r[i/fld.m] |= (1 << (i % fld.m) );
}

void bvector::from_poly (const polynomial&r, gf2m&fld)
{
	clear();
	resize (r.size() *fld.m, 0);
	for (uint i = 0; i < size(); ++i)
		item (i) = (r[i/fld.m] >> (i % fld.m) ) & 1;
}