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143 lines
3.3 KiB
143 lines
3.3 KiB
/* |
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* ZeroTier SDK - Network Virtualization Everywhere |
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* Copyright (C) 2011-2019 ZeroTier, Inc. https://www.zerotier.com/ |
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* |
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* This program is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU 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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* This program 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 this program. If not, see <http://www.gnu.org/licenses/>. |
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* |
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* -- |
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* |
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* You can be released from the requirements of the license by purchasing |
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* a commercial license. Buying such a license is mandatory as soon as you |
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* develop commercial closed-source software that incorporates or links |
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* directly against ZeroTier software without disclosing the source code |
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* of your own application. |
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*/ |
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/** |
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* @file |
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* |
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* Ring buffer implementation for network stack drivers |
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*/ |
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#include <memory.h> |
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#include <algorithm> |
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#include "RingBuffer.h" |
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bufElementType* RingBuffer::get_buf() |
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{ |
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return buf + begin; |
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} |
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size_t RingBuffer::produce(size_t n) |
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{ |
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n = std::min(n, getFree()); |
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if (n == 0) { |
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return n; |
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} |
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const size_t first_chunk = std::min(n, size - end); |
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end = (end + first_chunk) % size; |
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if (first_chunk < n) { |
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const size_t second_chunk = n - first_chunk; |
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end = (end + second_chunk) % size; |
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} |
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if (begin == end) { |
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wrap = true; |
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} |
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return n; |
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} |
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void RingBuffer::reset() |
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{ |
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consume(count()); |
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} |
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size_t RingBuffer::consume(size_t n) |
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{ |
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n = std::min(n, count()); |
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if (n == 0) { |
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return n; |
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} |
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if (wrap) { |
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wrap = false; |
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} |
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const size_t first_chunk = std::min(n, size - begin); |
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begin = (begin + first_chunk) % size; |
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if (first_chunk < n) { |
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const size_t second_chunk = n - first_chunk; |
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begin = (begin + second_chunk) % size; |
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} |
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return n; |
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} |
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size_t RingBuffer::write(const bufElementType * data, size_t n) |
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{ |
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n = std::min(n, getFree()); |
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if (n == 0) { |
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return n; |
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} |
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const size_t first_chunk = std::min(n, size - end); |
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memcpy(buf + end, data, first_chunk * sizeof(bufElementType)); |
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end = (end + first_chunk) % size; |
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if (first_chunk < n) { |
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const size_t second_chunk = n - first_chunk; |
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memcpy(buf + end, data + first_chunk, second_chunk * sizeof(bufElementType)); |
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end = (end + second_chunk) % size; |
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} |
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if (begin == end) { |
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wrap = true; |
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} |
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return n; |
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} |
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size_t RingBuffer::read(bufElementType * dest, size_t n) |
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{ |
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n = std::min(n, count()); |
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if (n == 0) { |
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return n; |
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} |
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if (wrap) { |
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wrap = false; |
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} |
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const size_t first_chunk = std::min(n, size - begin); |
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memcpy(dest, buf + begin, first_chunk * sizeof(bufElementType)); |
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begin = (begin + first_chunk) % size; |
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if (first_chunk < n) { |
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const size_t second_chunk = n - first_chunk; |
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memcpy(dest + first_chunk, buf + begin, second_chunk * sizeof(bufElementType)); |
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begin = (begin + second_chunk) % size; |
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} |
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return n; |
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} |
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size_t RingBuffer::count() |
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{ |
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if (end == begin) { |
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return wrap ? size : 0; |
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} |
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else if (end > begin) { |
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return end - begin; |
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} |
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else { |
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return size + end - begin; |
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} |
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} |
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size_t RingBuffer::getFree() |
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{ |
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return size - count(); |
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} |
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