fsfw/container/SimpleRingBuffer.h

130 lines
4.2 KiB
C++

#ifndef FSFW_CONTAINER_SIMPLERINGBUFFER_H_
#define FSFW_CONTAINER_SIMPLERINGBUFFER_H_
#include "RingBufferBase.h"
#include <cstddef>
/**
* @brief Circular buffer implementation, useful for buffering
* into data streams.
* @details
* Note that the deleteData() has to be called to increment the read pointer.
* This class allocated dynamically, so
* @ingroup containers
*/
class SimpleRingBuffer: public RingBufferBase<> {
public:
/**
* This constructor allocates a new internal buffer with the supplied size.
*
* @param size
* @param overwriteOld If the ring buffer is overflowing at a write
* operation, the oldest data will be overwritten.
* @param maxExcessBytes These additional bytes will be allocated in addtion
* to the specified size to accomodate contiguous write operations
* with getFreeElement.
*
*/
SimpleRingBuffer(const size_t size, bool overwriteOld,
size_t maxExcessBytes = 0);
/**
* This constructor takes an external buffer with the specified size.
* @param buffer
* @param size
* @param overwriteOld
* If the ring buffer is overflowing at a write operartion, the oldest data
* will be overwritten.
* @param maxExcessBytes
* If the buffer can accomodate additional bytes for contigous write
* operations with getFreeElement, this is the maximum allowed additional
* size
*/
SimpleRingBuffer(uint8_t* buffer, const size_t size, bool overwriteOld,
size_t maxExcessBytes = 0);
virtual ~SimpleRingBuffer();
/**
* Write to circular buffer and increment write pointer by amount.
* @param data
* @param amount
* @return -@c RETURN_OK if write operation was successfull
* -@c RETURN_FAILED if
*/
ReturnValue_t writeData(const uint8_t* data, size_t amount);
/**
* Returns a pointer to a free element. If the remaining buffer is
* not large enough, the data will be written past the actual size
* and the amount of excess bytes will be cached. This function
* does not increment the write pointer!
* @param writePointer Pointer to a pointer which can be used to write
* contiguous blocks into the ring buffer
* @param amount
* @return
*/
ReturnValue_t getFreeElement(uint8_t** writePointer, size_t amount);
/**
* This increments the write pointer and also copies the excess bytes
* to the beginning. It should be called if the write operation
* conducted after calling getFreeElement() was performed.
* @return
*/
void confirmBytesWritten(size_t amount);
virtual size_t getExcessBytes() const;
/**
* Helper functions which moves any excess bytes to the start
* of the ring buffer.
* @return
*/
virtual void moveExcessBytesToStart();
/**
* Read from circular buffer at read pointer.
* @param data
* @param amount
* @param incrementReadPtr
* If this is set to true, the read pointer will be incremented.
* If readRemaining is set to true, the read pointer will be incremented
* accordingly.
* @param readRemaining
* If this is set to true, the data will be read even if the amount
* specified exceeds the read data available.
* @param trueAmount [out]
* If readRemaining was set to true, the true amount read will be assigned
* to the passed value.
* @return
* - @c RETURN_OK if data was read successfully
* - @c RETURN_FAILED if not enough data was available and readRemaining
* was set to false.
*/
ReturnValue_t readData(uint8_t* data, size_t amount,
bool incrementReadPtr = false, bool readRemaining = false,
size_t* trueAmount = nullptr);
/**
* Delete data by incrementing read pointer.
* @param amount
* @param deleteRemaining
* If the amount specified is larger than the remaing size to read and this
* is set to true, the remaining amount will be deleted as well
* @param trueAmount [out]
* If deleteRemaining was set to true, the amount deleted will be assigned
* to the passed value.
* @return
*/
ReturnValue_t deleteData(size_t amount, bool deleteRemaining = false,
size_t* trueAmount = nullptr);
private:
static const uint8_t READ_PTR = 0;
uint8_t* buffer = nullptr;
size_t maxExcessBytes;
size_t excessBytes = 0;
};
#endif /* FSFW_CONTAINER_SIMPLERINGBUFFER_H_ */