boost/compute/container/dynamic_bitset.hpp
//---------------------------------------------------------------------------//
// Copyright (c) 2013-2014 Kyle Lutz <kyle.r.lutz@gmail.com>
//
// Distributed under the Boost Software License, Version 1.0
// See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt
//
// See http://boostorg.github.com/compute for more information.
//---------------------------------------------------------------------------//
#ifndef BOOST_COMPUTE_CONTAINER_DYNAMIC_BITSET_HPP
#define BOOST_COMPUTE_CONTAINER_DYNAMIC_BITSET_HPP
#include <boost/compute/lambda.hpp>
#include <boost/compute/algorithm/any_of.hpp>
#include <boost/compute/algorithm/fill.hpp>
#include <boost/compute/algorithm/transform_reduce.hpp>
#include <boost/compute/container/vector.hpp>
#include <boost/compute/functional/integer.hpp>
#include <boost/compute/types/fundamental.hpp>
namespace boost {
namespace compute {
/// \class dynamic_bitset
/// \brief The dynamic_bitset class contains a resizable bit array.
///
/// For example, to create a dynamic-bitset with space for 1000 bits on the
/// device:
/// \code
/// boost::compute::dynamic_bitset<> bits(1000, queue);
/// \endcode
///
/// The Boost.Compute \c dynamic_bitset class provides a STL-like API and is
/// modeled after the \c boost::dynamic_bitset class from Boost.
///
/// \see \ref vector "vector<T>"
template<class Block = ulong_, class Alloc = buffer_allocator<Block> >
class dynamic_bitset
{
public:
typedef Block block_type;
typedef Alloc allocator_type;
typedef vector<Block, Alloc> container_type;
typedef typename container_type::size_type size_type;
BOOST_STATIC_CONSTANT(size_type, bits_per_block = sizeof(block_type) * CHAR_BIT);
BOOST_STATIC_CONSTANT(size_type, npos = static_cast<size_type>(-1));
/// Creates a new dynamic bitset with storage for \p size bits. Initializes
/// all bits to zero.
dynamic_bitset(size_type size, command_queue &queue)
: m_bits(size / sizeof(block_type), queue.get_context()),
m_size(size)
{
// initialize all bits to zero
reset(queue);
}
/// Creates a new dynamic bitset as a copy of \p other.
dynamic_bitset(const dynamic_bitset &other)
: m_bits(other.m_bits),
m_size(other.m_size)
{
}
/// Copies the data from \p other to \c *this.
dynamic_bitset& operator=(const dynamic_bitset &other)
{
if(this != &other){
m_bits = other.m_bits;
m_size = other.m_size;
}
return *this;
}
/// Destroys the dynamic bitset.
~dynamic_bitset()
{
}
/// Returns the size of the dynamic bitset.
size_type size() const
{
return m_size;
}
/// Returns the number of blocks to store the bits in the dynamic bitset.
size_type num_blocks() const
{
return m_bits.size();
}
/// Returns the maximum possible size for the dynamic bitset.
size_type max_size() const
{
return m_bits.max_size() * bits_per_block;
}
/// Returns \c true if the dynamic bitset is empty (i.e. \c size() == \c 0).
bool empty() const
{
return size() == 0;
}
/// Returns the number of set bits (i.e. '1') in the bitset.
size_type count(command_queue &queue) const
{
ulong_ count = 0;
transform_reduce(
m_bits.begin(),
m_bits.end(),
&count,
popcount<block_type>(),
plus<ulong_>(),
queue
);
return static_cast<size_type>(count);
}
/// Resizes the bitset to contain \p num_bits. If the new size is greater
/// than the current size the new bits are set to zero.
void resize(size_type num_bits, command_queue &queue)
{
// resize bits
const size_type current_block_count = m_bits.size();
m_bits.resize(num_bits * bits_per_block, queue);
// fill new block with zeros (if new blocks were added)
const size_type new_block_count = m_bits.size();
if(new_block_count > current_block_count){
fill_n(
m_bits.begin() + current_block_count,
new_block_count - current_block_count,
block_type(0),
queue
);
}
// store new size
m_size = num_bits;
}
/// Sets the bit at position \p n to \c true.
void set(size_type n, command_queue &queue)
{
set(n, true, queue);
}
/// Sets the bit at position \p n to \p value.
void set(size_type n, bool value, command_queue &queue)
{
const size_type bit = n % bits_per_block;
const size_type block = n / bits_per_block;
// load current block
block_type block_value;
copy_n(m_bits.begin() + block, 1, &block_value, queue);
// update block value
if(value){
block_value |= (size_type(1) << bit);
}
else {
block_value &= ~(size_type(1) << bit);
}
// store new block
copy_n(&block_value, 1, m_bits.begin() + block, queue);
}
/// Returns \c true if the bit at position \p n is set (i.e. '1').
bool test(size_type n, command_queue &queue)
{
const size_type bit = n % (sizeof(block_type) * CHAR_BIT);
const size_type block = n / (sizeof(block_type) * CHAR_BIT);
block_type block_value;
copy_n(m_bits.begin() + block, 1, &block_value, queue);
return block_value & (size_type(1) << bit);
}
/// Flips the value of the bit at position \p n.
void flip(size_type n, command_queue &queue)
{
set(n, !test(n, queue), queue);
}
/// Returns \c true if any bit in the bitset is set (i.e. '1').
bool any(command_queue &queue) const
{
return any_of(
m_bits.begin(), m_bits.end(), lambda::_1 != block_type(0), queue
);
}
/// Returns \c true if all of the bits in the bitset are set to zero.
bool none(command_queue &queue) const
{
return !any(queue);
}
/// Sets all of the bits in the bitset to zero.
void reset(command_queue &queue)
{
fill(m_bits.begin(), m_bits.end(), block_type(0), queue);
}
/// Sets the bit at position \p n to zero.
void reset(size_type n, command_queue &queue)
{
set(n, false, queue);
}
/// Empties the bitset (e.g. \c resize(0)).
void clear()
{
m_bits.clear();
}
/// Returns the allocator used to allocate storage for the bitset.
allocator_type get_allocator() const
{
return m_bits.get_allocator();
}
private:
container_type m_bits;
size_type m_size;
};
} // end compute namespace
} // end boost namespace
#endif // BOOST_COMPUTE_CONTAINER_DYNAMIC_BITSET_HPP