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- /*
- CircularBuffer - An Arduino circular buffering library for arbitrary types.
-
- Created by Ivo Pullens, Emmission, 2014-2016 -- www.emmission.nl
-
- This library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- This library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with this library; if not, write to the Free Software
- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
- /**
- * @file CircularBuffer.h
- *
- * Circular buffering for arbitrary types.
- */
-
- #ifndef CircularBuffer_h
- #define CircularBuffer_h
-
- /**
- * The circular buffer class.
- * Pass the datatype to be stored in the buffer as template parameter.
- */
- template <class T> class CircularBuffer
- {
- public:
- /**
- * Constructor
- * @param buffer Preallocated buffer of at least size records.
- * @param size Number of records available in the buffer.
- */
- CircularBuffer(T* buffer, const uint8_t size )
- : m_size(size), m_buff(buffer)
- {
- clear();
- }
-
- /**
- * Clear all entries in the circular buffer.
- */
- void clear(void)
- {
- MY_CRITICAL_SECTION {
- m_front = 0;
- m_fill = 0;
- }
- }
-
- /**
- * Test if the circular buffer is empty.
- * @return True, when empty.
- */
- inline bool empty(void) const
- {
- bool empty;
- MY_CRITICAL_SECTION {
- empty = !m_fill;
- }
- return empty;
- }
-
- /**
- * Test if the circular buffer is full.
- * @return True, when full.
- */
- inline bool full(void) const
- {
- bool full;
- MY_CRITICAL_SECTION {
- full = m_fill == m_size;
- }
- return full;
- }
-
- /**
- * Return the number of records stored in the buffer.
- * @return number of records.
- */
- inline uint8_t available(void) const
- {
- uint8_t ret_value;
- MY_CRITICAL_SECTION {
- ret_value = m_fill;
- }
- return ret_value;
- }
-
- /**
- * Aquire unused record on front of the buffer, for writing.
- * After filling the record, it has to be pushed to actually
- * add it to the buffer.
- * @return Pointer to record, or NULL when buffer is full.
- */
- T* getFront(void) const
- {
- MY_CRITICAL_SECTION {
- if (!full())
- {
- return get(m_front);
- }
- }
- return static_cast<T*>(NULL);
- }
-
- /**
- * Push record to front of the buffer.
- * @param record Record to push. If record was aquired previously (using getFront) its
- * data will not be copied as it is already present in the buffer.
- * @return True, when record was pushed successfully.
- */
- bool pushFront(T* record)
- {
- MY_CRITICAL_SECTION {
- if (!full())
- {
- T* f = get(m_front);
- if (f != record) {
- *f = *record;
- }
- m_front = (m_front+1) % m_size;
- m_fill++;
- return true;
- }
- }
- return false;
- }
-
- /**
- * Aquire record on back of the buffer, for reading.
- * After reading the record, it has to be pop'ed to actually
- * remove it from the buffer.
- * @return Pointer to record, or NULL when buffer is empty.
- */
- T* getBack(void) const
- {
- MY_CRITICAL_SECTION {
- if (!empty())
- {
- return get(back());
- }
- }
- return static_cast<T*>(NULL);
- }
-
- /**
- * Remove record from back of the buffer.
- * @return True, when record was pop'ed successfully.
- */
- bool popBack(void)
- {
- MY_CRITICAL_SECTION {
- if (!empty())
- {
- m_fill--;
- return true;
- }
- }
- return false;
- }
-
- protected:
- /**
- * Internal getter for records.
- * @param idx Record index in buffer.
- * @return Ptr to record.
- */
- inline T * get(const uint8_t idx) const
- {
- return &(m_buff[idx]);
- }
-
- /**
- * Internal getter for index of last used record in buffer.
- * @return Index of last record.
- */
- inline uint8_t back(void) const
- {
- return (m_front - m_fill + m_size) % m_size;
- }
-
- const uint8_t m_size; //!< Total number of records that can be stored in the buffer.
- T* const m_buff; //!< Ptr to buffer holding all records.
- volatile uint8_t m_front; //!< Index of front element (not pushed yet).
- volatile uint8_t m_fill; //!< Amount of records currently pushed.
- };
-
- #endif // CircularBuffer_h
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