e928bcaf19
Like boost::dynamic_bitset, but less capable. On the other hand it avoids very large allocations, which are incurred by the bloom filter's bitset on even moderately sized sstables.
31 lines
896 B
C++
31 lines
896 B
C++
/*
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* Copyright (C) 2015 Cloudius Systems, Ltd.
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*/
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#include "large_bitset.hh"
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#include <algorithm>
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#include <seastar/core/align.hh>
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large_bitset::large_bitset(size_t nr_bits) : _nr_bits(nr_bits) {
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auto nr_blocks = align_up(nr_bits, bits_per_block()) / bits_per_block();
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_storage.reserve(nr_blocks);
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size_t nr_ints = align_up(nr_bits, bits_per_int()) / bits_per_int();
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while (nr_ints) {
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auto now = std::min(ints_per_block(), nr_ints);
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_storage.push_back(std::make_unique<int_type[]>(now));
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std::fill_n(_storage.back().get(), now, 0);
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nr_ints -= now;
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}
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}
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void
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large_bitset::clear() {
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size_t nr_ints = align_up(_nr_bits, bits_per_int()) / bits_per_int();
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auto bp = _storage.begin();
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while (nr_ints) {
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auto now = std::min(ints_per_block(), nr_ints);
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std::fill_n(bp++->get(), now, 0);
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nr_ints -= now;
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}
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}
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