Francois Berder / CircularBuffer

Small library for using circular buffers

Dependents:   CircularBufferExample

This library provides circular buffers. The main difference with other circular buffer libraries is that it does not use dynamic memory allocation for storing data. Instead, the buffer is allocated statically.

Three types of buffer exist by default :

  • SmallCircularBuffer (32 bytes)
  • MediumCircularBuffer (128 bytes)
  • BigCircularBuffer (512 bytes)

You can also define buffers with specific size :

CircularBuffer<4> buffer;    // 4 bytes buffer
CircularBuffer<102> buffer2; // 102 bytes buffer

Import programCircularBufferExample

This example shows how to use the CircularBuffer library.

Last commit 20 Sep 2013 by Francois Berder

CircularBuffer.h

Committer:
feb11
Date:
2013-09-20
Revision:
2:6f3630f5fa06
Parent:
1:9953890d59e2
Child:
3:9a45d6675e65

File content as of revision 2:6f3630f5fa06:

#ifndef CIRCULAR_BUFFER_H
#define CIRCULAR_BUFFER_H

template<size_t T>
class CircularBuffer
{
    public :
    
        CircularBuffer();
        
        uint32_t read(uint8_t *data, uint32_t length);
        uint32_t write(uint8_t *data, uint32_t length);
        uint32_t getCapacity() const;
        uint32_t getSize() const;
        
    private :
    
        uint16_t readIndex, writeIndex;
        uint8_t buffer[T]; 
    
};

template<size_t T>
CircularBuffer<T>::CircularBuffer():
readIndex(0),
writeIndex(0)
{
}

template<size_t T>
uint32_t CircularBuffer<T>::read(uint8_t *data, uint32_t length)
{
    uint32_t n = 0;
    while(n < length && getSize() < T)
    {
        if(readIndex == T)
            readIndex = 0;
        data[n++] = buffer[readIndex++];
    }
    
    return n;
}

template<size_t T>
uint32_t CircularBuffer<T>::write(uint8_t *data, uint32_t length)
{
    uint32_t n = 0;
    while(n < length && getSize() > 0)
    {
        if(writeIndex == T)
            writeIndex = 0;
        buffer[writeIndex++] = data[n++];
    }
    
    return n;
}

template<size_t T>
uint32_t CircularBuffer<T>::getCapacity() const
{
    return T;
}
        
template<size_t T>
uint32_t CircularBuffer<T>::getSize() const
{
    return ((writeIndex >= readIndex) ? (T - writeIndex + readIndex) : (readIndex - writeIndex));
}

typedef CircularBuffer<32> SmallCircularBuffer;
typedef CircularBuffer<128> MediumCircularBuffer;
typedef CircularBuffer<512> BigCircularBuffer;

#endif