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author | px4dev <px4@purgatory.org> | 2013-08-03 18:29:26 -0700 |
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committer | px4dev <px4@purgatory.org> | 2013-08-03 18:29:26 -0700 |
commit | 42f2794dee691e03dd8a47ee80d07b60ab2b277d (patch) | |
tree | 9b1f01c41b5c8157449025e392e00d75aaa316d9 /src/drivers | |
parent | 9a97001cc849038223aa5eda6a76ac0fc6f1094f (diff) | |
parent | 234ad240818e6486d39a3149597956a534d59ea0 (diff) | |
download | px4-firmware-42f2794dee691e03dd8a47ee80d07b60ab2b277d.tar.gz px4-firmware-42f2794dee691e03dd8a47ee80d07b60ab2b277d.tar.bz2 px4-firmware-42f2794dee691e03dd8a47ee80d07b60ab2b277d.zip |
Merge branch 'master' into mpu6k_queue
Diffstat (limited to 'src/drivers')
-rw-r--r-- | src/drivers/device/ringbuffer.h | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/src/drivers/device/ringbuffer.h b/src/drivers/device/ringbuffer.h new file mode 100644 index 000000000..37686fdbe --- /dev/null +++ b/src/drivers/device/ringbuffer.h @@ -0,0 +1,192 @@ +/**************************************************************************** + * + * Copyright (C) 2013 PX4 Development Team. All rights reserved. + * Author: Lorenz Meier <lm@inf.ethz.ch> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name PX4 nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/** + * @file ringbuffer.h + * + * A simple ringbuffer template. + */ + +#pragma once + +template<typename T> +class RingBuffer { +public: + RingBuffer(unsigned size); + virtual ~RingBuffer(); + + /** + * Put an item into the buffer. + * + * @param val Item to put + * @return true if the item was put, false if the buffer is full + */ + bool put(T &val); + + /** + * Put an item into the buffer. + * + * @param val Item to put + * @return true if the item was put, false if the buffer is full + */ + bool put(const T &val); + + /** + * Get an item from the buffer. + * + * @param val Item that was gotten + * @return true if an item was got, false if the buffer was empty. + */ + bool get(T &val); + + /** + * Get an item from the buffer (scalars only). + * + * @return The value that was fetched, or zero if the buffer was + * empty. + */ + T get(void); + + /* + * Get the number of slots free in the buffer. + * + * @return The number of items that can be put into the buffer before + * it becomes full. + */ + unsigned space(void); + + /* + * Get the number of items in the buffer. + * + * @return The number of items that can be got from the buffer before + * it becomes empty. + */ + unsigned count(void); + + /* + * Returns true if the buffer is empty. + */ + bool empty() { return _tail == _head; } + + /* + * Returns true if the buffer is full. + */ + bool full() { return _next(_head) == _tail; } + +private: + T *const _buf; + const unsigned _size; + volatile unsigned _head; /**< insertion point */ + volatile unsigned _tail; /**< removal point */ + + unsigned _next(unsigned index); +}; + +template <typename T> +RingBuffer<T>::RingBuffer(unsigned size) : + _buf(new T[size + 1]), + _size(size), + _head(size), + _tail(size) +{} + +template <typename T> +RingBuffer<T>::~RingBuffer() +{ + if (_buf != nullptr) + delete[] _buf; +} + +template <typename T> +bool RingBuffer<T>::put(T &val) +{ + unsigned next = _next(_head); + if (next != _tail) { + _buf[_head] = val; + _head = next; + return true; + } else { + return false; + } +} + +template <typename T> +bool RingBuffer<T>::put(const T &val) +{ + unsigned next = _next(_head); + if (next != _tail) { + _buf[_head] = val; + _head = next; + return true; + } else { + return false; + } +} + +template <typename T> +bool RingBuffer<T>::get(T &val) +{ + if (_tail != _head) { + val = _buf[_tail]; + _tail = _next(_tail); + return true; + } else { + return false; + } +} + +template <typename T> +T RingBuffer<T>::get(void) +{ + T val; + return get(val) ? val : 0; +} + +template <typename T> +unsigned RingBuffer<T>::space(void) +{ + return (_tail >= _head) ? (_size - (_tail - _head)) : (_head - _tail - 1); +} + +template <typename T> +unsigned RingBuffer<T>::count(void) +{ + return _size - space(); +} + +template <typename T> +unsigned RingBuffer<T>::_next(unsigned index) +{ + return (0 == index) ? _size : (index - 1); +} |