65 lines
1.5 KiB
C++
65 lines
1.5 KiB
C++
#ifndef SPAN_ITERATOR_H
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#define SPAN_ITERATOR_H
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#include "persistent-data/space_map.h"
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#include "persistent-data/run_set.h"
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#include <set>
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//----------------------------------------------------------------
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namespace persistent_data {
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class subtracting_span_iterator : public space_map::span_iterator {
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public:
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typedef typename base::run_set<block_address> block_set;
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typedef space_map::span span;
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subtracting_span_iterator(block_address max,
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span_iterator &sub_it,
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block_set const &forbidden_blocks)
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: max_(max) {
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for (maybe_span ms = sub_it.first(); ms; ms = sub_it.next())
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runs_.add(ms->first, ms->second);
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block_set bs(forbidden_blocks);
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runs_.negate();
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runs_.merge(bs);
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runs_.negate();
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}
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virtual maybe_span first() {
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current_ = runs_.begin();
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return get_current();
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}
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virtual maybe_span next() {
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if (current_ != runs_.end())
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++current_;
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return get_current();
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}
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private:
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maybe_span get_current() {
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// FIXME: unsafe deref of begin and end
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return (current_ == runs_.end()) ?
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maybe_span() :
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maybe_span(std::make_pair(maybe_default(current_->begin_, 0ULL),
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maybe_default(current_->end_, max_)));
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}
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typedef boost::optional<block_address> maybe;
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static block_address maybe_default(maybe const &m, block_address default_) {
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return m ? *m : default_;
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}
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block_address max_;
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block_set runs_;
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block_set::const_iterator current_;
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};
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}
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//----------------------------------------------------------------
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#endif
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