0994e8b5e2
This utility function converts a potentially large number to a compact representation, composed of at most 4 digits and a letter appropriate to the power of two the number has to multiplied with to arrive to the original number (with some loss of precision). The different powers of two are the conventional 2 ** (N * 10) variants: * N=0: (B)ytes * N=1: (K)bytes * N=2: (M)bytes * N=3: (G)bytes * N=4: (T)bytes Examples: * 87665 will be converted to 87K * 1024 will be converted to 1K
64 lines
1.8 KiB
C++
64 lines
1.8 KiB
C++
/*
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* This file is part of Scylla.
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*
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* Scylla is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Scylla is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* Copyright (C) 2020 ScyllaDB
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*/
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#include "utils/human_readable.hh"
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#include <array>
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#include <ostream>
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namespace utils {
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std::ostream& operator<<(std::ostream& os, const human_readable_value& val) {
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os << val.value;
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if (val.suffix) {
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os << val.suffix;
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}
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return os;
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}
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static human_readable_value to_human_readable_value(uint64_t value, uint64_t step, uint64_t precision, const std::array<char, 5>& suffixes) {
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if (!value) {
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return {0, suffixes[0]};
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}
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uint64_t result = value;
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uint64_t remainder = 0;
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unsigned i = 0;
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// If there is no remainder we go below precision because we don't loose any.
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while (((!remainder && result >= step) || result >= precision)) {
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remainder = result % step;
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result /= step;
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if (i == suffixes.size()) {
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break;
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} else {
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++i;
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}
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}
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return {uint16_t(remainder < (step / 2) ? result : result + 1), suffixes[i]};
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}
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human_readable_value to_hr_size(uint64_t size) {
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const std::array<char, 5> suffixes = {'B', 'K', 'M', 'G', 'T'};
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return to_human_readable_value(size, 1024, 8192, suffixes);
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}
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} // namespace utils
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