thin-provisioning-tools/btree.h

#ifndef BTREE_H
#define BTREE_H

#include "endian.h"
#include "transaction_manager.h"

//----------------------------------------------------------------

namespace persistent_data {
	template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
	class btree {
	public:
		typedef uint64_t key[Levels];
		typedef typename ValueTraits::value_type value_type;
		typedef boost::optional<value_type> maybe_value;
		typedef boost::optional<std::pair<unsigned, value_type> > maybe_pair;
		typedef boost::shared_ptr<btree<Levels, ValueTraits, BlockSize> > ptr;
		typedef typename block_manager<BlockSize>::read_ref read_ref;
		typedef typename block_manager<BlockSize>::write_ref write_ref;

		btree(typename persistent_data::transaction_manager<BlockSize>::ptr tm);
		btree(typename transaction_manager<BlockSize>::ptr tm,
		      block_address root);
		~btree();

		maybe_value lookup(key const &key) const;
		maybe_pair lookup_le(key const &key) const;
		maybe_pair lookup_ge(key const &key) const;

		void insert(key const &key, typename ValueTraits::value_type const &value);
		void remove(key const &key);

		void set_root(block_address root);
		block_address get_root() const;

		ptr clone() const;

		// free the on disk btree when the destructor is called
		void destroy();

	private:
		typename persistent_data::transaction_manager<BlockSize>::ptr tm_;
		bool destroy_;
		block_address root_;
	};

	struct uint64_traits {
		typedef base::__le64 disk_type;
		typedef uint64_t value_type;

		static value_type construct(void *data) {
			// extra memcpy because I'm paranoid about alignment issues
			base::__le64 disk;

			::memcpy(&disk, data, sizeof(disk));
			return base::to_cpu<uint64_t>(disk);
		}
	};
};

#include "btree.tcc"

//----------------------------------------------------------------

#endif