gplib/include/gp/bloomfilter.hpp

#pragma once

#include <gp/algorithm/foreach.hpp>
#include <gp/algorithm/tmp_manip.hpp>
#include <gp/array.hpp>

#include <atomic>

#include <stdint.h>

namespace gp {
	template<typename hash_type = uint64_t, uint8_t magnitude = 19, bool threading = false>
	class bloomfilter {
		constexpr static size_t phys_size = (1 << magnitude) / 32;
		gp::array<
			typename gp::either< threading, 
				std::atomic_uint32_t, 
				uint32_t
			>::type,
			phys_size
		> data;

		template<typename T>
		static void set_bit(T* value, const int v_pos) {
			*value |= (1 << v_pos);
		}

		template<typename T>
		static bool get_bit(T* value, const int v_pos) {
			return (*value >> v_pos) & 1;
		}

	public:
		bloomfilter()
		{
			fill(data, 0);
		}

		void set_hash(hash_type v)
		{
			const size_t modulo = v & ((1 << magnitude)-1);
			const size_t p_pos  = modulo / 32;
			const size_t v_pos  = modulo % 32;

			set_bit(&data[p_pos], v_pos);
		}

		bool test_hash(hash_type v)
		{
			const size_t modulo = v & ((1 << magnitude)-1);
			const size_t p_pos  = modulo / 32;
			const size_t v_pos  = modulo % 32;

			return get_bit(&data[p_pos], v_pos);
		}
	};
}