123 lines
2.6 KiB
C++
123 lines
2.6 KiB
C++
#ifndef SPACE_MAP_H
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#define SPACE_MAP_H
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#include "block.h"
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#include "block_counter.h"
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#include <boost/shared_ptr.hpp>
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#include <boost/optional.hpp>
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//----------------------------------------------------------------
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namespace persistent_data {
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typedef uint32_t ref_t;
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class space_map {
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public:
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typedef boost::shared_ptr<space_map> ptr;
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virtual ~space_map() {};
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virtual block_address get_nr_blocks() const = 0;
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virtual block_address get_nr_free() const = 0;
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virtual ref_t get_count(block_address b) const = 0;
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virtual void set_count(block_address b, ref_t c) = 0;
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virtual void commit() = 0;
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virtual void inc(block_address b) = 0;
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virtual void dec(block_address b) = 0;
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// FIXME: change these to return an optional, failure is
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// not that rare if we're restricting the area that's
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// searched.
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typedef boost::optional<block_address> maybe_block;
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virtual maybe_block new_block() = 0;
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virtual maybe_block new_block(block_address begin, block_address end) = 0;
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virtual bool count_possibly_greater_than_one(block_address b) const = 0;
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virtual void extend(block_address extra_blocks) = 0;
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struct iterator {
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virtual ~iterator() {}
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virtual void operator() (block_address b, ref_t c) = 0;
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};
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virtual void iterate(iterator &it) const {
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throw std::runtime_error("not implemented");
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}
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};
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class persistent_space_map : public space_map {
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public:
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typedef boost::shared_ptr<persistent_space_map> ptr;
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virtual size_t root_size() const = 0;
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virtual void copy_root(void *dest, size_t len) const = 0;
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};
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class checked_space_map : public persistent_space_map {
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public:
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typedef boost::shared_ptr<checked_space_map> ptr;
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virtual void check(block_counter &counter) const {
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throw std::runtime_error("not implemented");
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}
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virtual ptr clone() const = 0;
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};
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class sm_adjust {
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public:
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sm_adjust(space_map::ptr sm, block_address b, int delta)
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: sm_(sm),
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b_(b),
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delta_(delta) {
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adjust_count(delta_);
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}
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~sm_adjust() {
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adjust_count(-delta_);
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}
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void release() {
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delta_ = 0;
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}
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private:
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void adjust_count(int delta) {
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if (delta == 1)
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sm_->inc(b_);
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else if (delta == -1)
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sm_->dec(b_);
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else
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sm_->set_count(b_, sm_->get_count(b_) + delta);
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}
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space_map::ptr sm_;
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block_address b_;
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int delta_;
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};
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class sm_decrementer {
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public:
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sm_decrementer(space_map::ptr sm, block_address b);
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~sm_decrementer();
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void dont_bother();
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private:
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space_map::ptr sm_;
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block_address b_;
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bool released_;
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};
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}
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//----------------------------------------------------------------
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#endif
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