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mbed-os/platform/CircularBuffer.h
- Committer:
- kadonotakashi
- Date:
- 2018-10-10
- Revision:
- 0:8fdf9a60065b
File content as of revision 0:8fdf9a60065b:
/* mbed Microcontroller Library * Copyright (c) 2015 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef MBED_CIRCULARBUFFER_H #define MBED_CIRCULARBUFFER_H #include "platform/mbed_critical.h" #include "platform/mbed_assert.h" namespace mbed { namespace internal { /* Detect if CounterType of the Circular buffer is of unsigned type. */ template<typename T> struct is_unsigned { static const bool value = false; }; template<> struct is_unsigned<unsigned char> { static const bool value = true; }; template<> struct is_unsigned<unsigned short> { static const bool value = true; }; template<> struct is_unsigned<unsigned int> { static const bool value = true; }; template<> struct is_unsigned<unsigned long> { static const bool value = true; }; template<> struct is_unsigned<unsigned long long> { static const bool value = true; }; }; /** \addtogroup platform */ /** @{*/ /** * \defgroup platform_CircularBuffer CircularBuffer functions * @{ */ /** Templated Circular buffer class * * @note Synchronization level: Interrupt safe * @note CounterType must be unsigned and consistent with BufferSize */ template<typename T, uint32_t BufferSize, typename CounterType = uint32_t> class CircularBuffer { public: CircularBuffer() : _head(0), _tail(0), _full(false) { MBED_STATIC_ASSERT( internal::is_unsigned<CounterType>::value, "CounterType must be unsigned" ); MBED_STATIC_ASSERT( (sizeof(CounterType) >= sizeof(uint32_t)) || (BufferSize < (((uint64_t) 1) << (sizeof(CounterType) * 8))), "Invalid BufferSize for the CounterType" ); } ~CircularBuffer() { } /** Push the transaction to the buffer. This overwrites the buffer if it's * full * * @param data Data to be pushed to the buffer */ void push(const T &data) { core_util_critical_section_enter(); if (full()) { _tail++; if (_tail == BufferSize) { _tail = 0; } } _pool[_head++] = data; if (_head == BufferSize) { _head = 0; } if (_head == _tail) { _full = true; } core_util_critical_section_exit(); } /** Pop the transaction from the buffer * * @param data Data to be popped from the buffer * @return True if the buffer is not empty and data contains a transaction, false otherwise */ bool pop(T &data) { bool data_popped = false; core_util_critical_section_enter(); if (!empty()) { data = _pool[_tail++]; if (_tail == BufferSize) { _tail = 0; } _full = false; data_popped = true; } core_util_critical_section_exit(); return data_popped; } /** Check if the buffer is empty * * @return True if the buffer is empty, false if not */ bool empty() const { core_util_critical_section_enter(); bool is_empty = (_head == _tail) && !_full; core_util_critical_section_exit(); return is_empty; } /** Check if the buffer is full * * @return True if the buffer is full, false if not */ bool full() const { core_util_critical_section_enter(); bool full = _full; core_util_critical_section_exit(); return full; } /** Reset the buffer * */ void reset() { core_util_critical_section_enter(); _head = 0; _tail = 0; _full = false; core_util_critical_section_exit(); } /** Get the number of elements currently stored in the circular_buffer */ CounterType size() const { core_util_critical_section_enter(); CounterType elements; if (!_full) { if (_head < _tail) { elements = BufferSize + _head - _tail; } else { elements = _head - _tail; } } else { elements = BufferSize; } core_util_critical_section_exit(); return elements; } /** Peek into circular buffer without popping * * @param data Data to be peeked from the buffer * @return True if the buffer is not empty and data contains a transaction, false otherwise */ bool peek(T &data) const { bool data_updated = false; core_util_critical_section_enter(); if (!empty()) { data = _pool[_tail]; data_updated = true; } core_util_critical_section_exit(); return data_updated; } private: T _pool[BufferSize]; CounterType _head; CounterType _tail; bool _full; }; /**@}*/ /**@}*/ } #endif