bit_vector.cpp

#include <iostream>
#include "bit_vector.h"

bool findCommonOne(bit_vector* a, bit_vector* b) {
	int num_int64 = a->num_bytes/8;
	int left_bytes = a->num_bytes%8;
	uint64_t tmp = 0l;
	for (int i = 0; i < num_int64; i++) {
		tmp = static_cast<uint64_t*>(a->_db)[i]&static_cast<uint64_t*>(b->_db)[i];
		if (tmp!=0)
			return true;
	}
	for (int i = 0; i < left_bytes; i++) {
		tmp = static_cast<unsigned char*>(a->_db)[i]&static_cast<unsigned char*>(b->_db)[i];
		if (tmp!=0)
			return true;
	}
	return false;
}

bit_vector::bit_vector(): _num_bits(0), _db(NULL)
{
	num_bytes = 0;
}

bit_vector::bit_vector(int64_t num_bits)
    : _num_bits(num_bits), _db(NULL)
{
  num_bytes = _num_bits / 8;
  if (_num_bits % 8 != 0)
  {
    num_bytes += 1;
  }

  if ((size_t)num_bytes < num_bytes)
  {
    std::cout << "Error: won't be able to calloc " << num_bytes << " bytes on architecture with sizeof(size_t) " << sizeof(size_t) << "\n";
  }

  if ((_db = calloc(num_bytes, 1)) == NULL)
  {
    cout << "calloc bit_vector()" << endl;
    std::cout << "num_bytes " << num_bytes << "\n";
    exit(1);
  }
}

bit_vector::~bit_vector()
{
	free(_db);
}