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da34e5e2c8
This adds a reusable class for a FIFO ringbuffer that accepts variable length packets. It is using the Ringbuffer class internally. Signed-off-by: Julian Oes <julian@oes.ch>
107 lines
3.3 KiB
C++
107 lines
3.3 KiB
C++
/****************************************************************************
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*
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* Copyright (C) 2023 PX4 Development Team. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name PX4 nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#include "VariableLengthRingbuffer.hpp"
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#include <assert.h>
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#include <string.h>
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VariableLengthRingbuffer::~VariableLengthRingbuffer()
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{
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deallocate();
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}
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bool VariableLengthRingbuffer::allocate(size_t buffer_size)
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{
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return _ringbuffer.allocate(buffer_size);
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}
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void VariableLengthRingbuffer::deallocate()
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{
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_ringbuffer.deallocate();
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}
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bool VariableLengthRingbuffer::push_back(const uint8_t *packet, size_t packet_len)
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{
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if (packet_len == 0 || packet == nullptr) {
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// Nothing to add, we better don't try.
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return false;
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}
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size_t space_required = packet_len + sizeof(Header);
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if (space_required > _ringbuffer.space_available()) {
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return false;
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}
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Header header{static_cast<uint32_t>(packet_len)};
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bool result = _ringbuffer.push_back(reinterpret_cast<const uint8_t * >(&header), sizeof(header));
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assert(result);
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result = _ringbuffer.push_back(packet, packet_len);
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assert(result);
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// In case asserts are commented out to prevent unused warnings.
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(void)result;
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return true;
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}
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size_t VariableLengthRingbuffer::pop_front(uint8_t *buf, size_t buf_max_len)
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{
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if (buf == nullptr) {
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// User needs to supply a valid pointer.
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return 0;
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}
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// Check next header
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Header header;
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if (_ringbuffer.pop_front(reinterpret_cast<uint8_t *>(&header), sizeof(header)) < sizeof(header)) {
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return 0;
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}
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// We can't fit the packet into the user supplied buffer.
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// This should never happen as the user has to supply a big // enough buffer.
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assert(static_cast<uint32_t>(header.len) <= buf_max_len);
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size_t bytes_read = _ringbuffer.pop_front(buf, header.len);
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assert(bytes_read == header.len);
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return bytes_read;
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}
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