audio-drain/audio/drain/CircularBuffer.h

/** @file
 * @author Edouard DUPIN 
 * @copyright 2011, Edouard DUPIN, all right reserved
 * @license APACHE v2.0 (see license file)
 */
#pragma once

#include <etk/types.h>
#include <vector>
#include <chrono>
#include <audio/Time.h>
#include <audio/Duration.h>

namespace audio {
	namespace drain {
		/**
		 * For these functions we have 4 solutions :
		 *  - Free Buffer
		 *             ----------------------------------------------------------
		 *      m_data |                            |                           |
		 *             ----------------------------------------------------------
		 *                                          m_write
		 *                                          m_read
		 *  - Full Buffer
		 *             ----------------------------------------------------------
		 *      m_data |****************************|***************************|
		 *             ----------------------------------------------------------
		 *                                          m_write
		 *                                          m_read
		 *  - Buffer in used
		 *             ----------------------------------------------------------
		 *      m_data |                |********************|                  |
		 *             ----------------------------------------------------------
		 *                              m_read                m_write
		 *  - Buffer out used
		 *             ----------------------------------------------------------
		 *      m_data |****************|                    |******************|
		 *             ----------------------------------------------------------
		 *                              m_read                m_write
		 */
		class CircularBuffer {
			private:
				std::vector<uint8_t> m_data; //!< data pointer
				void* m_write; //!< write pointer
				void* m_read; //!< read pointer
				audio::Time m_timeRead; //!< current read time
				uint32_t m_frequency;
				// TODO : Remove the m_size ==> this is a bad element to be mutex-less
				size_t m_size; //!< number of chunk availlable in this buffer
				size_t m_capacity; //!< number of chunk available in this Buffer
				size_t m_sizeChunk; //!< Size of one chunk (in byte)
			public:
				CircularBuffer();
				~CircularBuffer();
				/**
				 * @brief copy contructor.
				 * @param[in] _obj Circular buffer object
				 */
				CircularBuffer(const audio::drain::CircularBuffer& _obj);
				/**
				 * @brief copy operator.
				 * @param[in] _obj Circular buffer object
				 */
				CircularBuffer& operator=(const audio::drain::CircularBuffer& _obj);
				/**
				 * @brief set the capacity of the circular buffer.
				 * @param[in] _capacity Number of chunk in the buffer.
				 * @param[in] _chunkSize Size of one chunk.
				 * @param[in] _frequency Frequency of the buffer
				 */
				void setCapacity(size_t _capacity, size_t _chunkSize, uint32_t _frequency);
				/**
				 * @brief set the capacity of the circular buffer.
				 * @param[in] _capacity time in millisecond stored in the buffer.
				 * @param[in] _chunkSize Size of one chunk.
				 * @param[in] _frequency Frequency of the buffer
				 */
				void setCapacity(std::chrono::milliseconds _capacity, size_t _chunkSize, uint32_t _frequency);
				void setCapacity(std::chrono::microseconds _capacity, size_t _chunkSize, uint32_t _frequency) {
					setCapacity(std::chrono::milliseconds(_capacity.count()/1000), _chunkSize, _frequency);
				}
				/**
				 * @brief get free size of the buffer.
				 * @return Number of free chunk.
				 */
				size_t getFreeSize() const;
				/**
				 * @brief Get number of chunk in the buffer.
				 * @return number of chunk.
				 */
				size_t getSize() const {
					return m_size;
				}
				/**
				 * @brief Get number of chunk that can be set in the buffer.
				 * @return number of chunk.
				 */
				size_t getCapacity() const {
					return m_capacity;
				}
				/**
				 * @brief Write chunk in the buffer.
				 * @param[in] _data Pointer on the data.
				 * @param[in] _nbChunk number of chunk to copy.
				 * @param[in] _time Time to start write data (if before end ==> not replace data, write only if after end)
				 * @return Number of chunk copied.
				 */
				size_t write(const void* _data, size_t _nbChunk, const audio::Time& _time);
				size_t write(const void* _data, size_t _nbChunk);
				/**
				 * @brief Read Chunk from the buffer to the pointer data.
				 * @param[out] _data Pointer on the data.
				 * @param[in] _nbChunk number of chunk to copy.
				 * @param[in] _time Time to start read data (if before start ==> add 0 at start, if after, remove unread data)
				 * @return Number of chunk copied.
				 */
				size_t read(void* _data, size_t _nbChunk, const audio::Time& _time);
				//! @previous
				size_t read(void* _data, size_t _nbChunk);
				void setReadPosition(const audio::Time& _time);
				
				audio::Time getReadTimeStamp() {
					return m_timeRead;
				}
				/**
				 * @brief Clear the buffer.
				 */
				void clear();
			private:
				/**
				 * @brief Get number of free chunks before end of buffer.
				 * @return Number of chunk.
				 */
				size_t getFreeSizeBeforEnd() const;
				/**
				 * @brief Get number of used chunks before end of buffer.
				 * @return Number of chunk.
				 */
				size_t getUsedSizeBeforEnd() const;
		};
	}
}