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@4:e15dee1d59ee, 2013-09-20 (annotated)

Committer:
feb11
Date:
Fri Sep 20 10:32:30 2013 +0000
Revision:
4:e15dee1d59ee
Parent:
3:9a45d6675e65
Child:
5:8204677dc3c4
added comments

Who changed what in which revision?

UserRevisionLine numberNew contents of line
feb11 0:5d058c917599 1 #ifndef CIRCULAR_BUFFER_H
feb11 0:5d058c917599 2 #define CIRCULAR_BUFFER_H
feb11 0:5d058c917599 3
feb11 4:e15dee1d59ee 4 /** This class implements a static circular buffer.
feb11 4:e15dee1d59ee 5 */
feb11 0:5d058c917599 6 template<size_t T>
feb11 0:5d058c917599 7 class CircularBuffer
feb11 0:5d058c917599 8 {
feb11 0:5d058c917599 9 public :
feb11 0:5d058c917599 10
feb11 4:e15dee1d59ee 11 /** Default constructor
feb11 4:e15dee1d59ee 12 */
feb11 0:5d058c917599 13 CircularBuffer();
feb11 0:5d058c917599 14
feb11 4:e15dee1d59ee 15 /** Reads data from buffer
feb11 4:e15dee1d59ee 16
feb11 4:e15dee1d59ee 17 \param data output buffer
feb11 4:e15dee1d59ee 18 \param length Maximum number of bytes to read
feb11 4:e15dee1d59ee 19 \return Number of bytes read
feb11 4:e15dee1d59ee 20
feb11 4:e15dee1d59ee 21 \note The return value cannot exceed max(length,capacity)
feb11 4:e15dee1d59ee 22 */
feb11 2:6f3630f5fa06 23 uint32_t read(uint8_t *data, uint32_t length);
feb11 4:e15dee1d59ee 24
feb11 4:e15dee1d59ee 25 /** Writes data in buffer
feb11 4:e15dee1d59ee 26
feb11 4:e15dee1d59ee 27 \param data input buffer
feb11 4:e15dee1d59ee 28 \param length Maximum number of bytes to write
feb11 4:e15dee1d59ee 29 \return Number of bytes wrote
feb11 4:e15dee1d59ee 30
feb11 4:e15dee1d59ee 31 \note The return value cannot exceed max(length,capacity)
feb11 4:e15dee1d59ee 32 */
feb11 2:6f3630f5fa06 33 uint32_t write(uint8_t *data, uint32_t length);
feb11 3:9a45d6675e65 34
feb11 4:e15dee1d59ee 35 /** Returns the total capacity of this buffer
feb11 4:e15dee1d59ee 36 \return Capacity of buffer
feb11 4:e15dee1d59ee 37 */
feb11 2:6f3630f5fa06 38 uint32_t getCapacity() const;
feb11 4:e15dee1d59ee 39
feb11 4:e15dee1d59ee 40 /** Returns the number of bytes available in the buffer
feb11 4:e15dee1d59ee 41 \return Number of bytes available in the buffer
feb11 4:e15dee1d59ee 42 */
feb11 3:9a45d6675e65 43 uint32_t getSize() const;
feb11 4:e15dee1d59ee 44
feb11 4:e15dee1d59ee 45 /** Checks if this buffer is empty
feb11 4:e15dee1d59ee 46 \return True if the buffer is empty, false otherwise
feb11 4:e15dee1d59ee 47 */
feb11 3:9a45d6675e65 48 bool isEmpty() const;
feb11 4:e15dee1d59ee 49
feb11 4:e15dee1d59ee 50 /** Checks if this buffer is full
feb11 4:e15dee1d59ee 51 \return True if the buffer is full, false otherwise
feb11 4:e15dee1d59ee 52 */
feb11 3:9a45d6675e65 53 bool isFull() const;
feb11 2:6f3630f5fa06 54
feb11 0:5d058c917599 55 private :
feb11 0:5d058c917599 56
feb11 2:6f3630f5fa06 57 uint16_t readIndex, writeIndex;
feb11 0:5d058c917599 58 uint8_t buffer[T];
feb11 0:5d058c917599 59
feb11 0:5d058c917599 60 };
feb11 0:5d058c917599 61
feb11 0:5d058c917599 62 template<size_t T>
feb11 0:5d058c917599 63 CircularBuffer<T>::CircularBuffer():
feb11 3:9a45d6675e65 64 readIndex(T),
feb11 1:9953890d59e2 65 writeIndex(0)
feb11 0:5d058c917599 66 {
feb11 0:5d058c917599 67 }
feb11 0:5d058c917599 68
feb11 0:5d058c917599 69 template<size_t T>
feb11 2:6f3630f5fa06 70 uint32_t CircularBuffer<T>::read(uint8_t *data, uint32_t length)
feb11 0:5d058c917599 71 {
feb11 2:6f3630f5fa06 72 uint32_t n = 0;
feb11 3:9a45d6675e65 73 while(n < length && getSize() > 0)
feb11 0:5d058c917599 74 {
feb11 2:6f3630f5fa06 75 if(readIndex == T)
feb11 2:6f3630f5fa06 76 readIndex = 0;
feb11 2:6f3630f5fa06 77 data[n++] = buffer[readIndex++];
feb11 0:5d058c917599 78 }
feb11 0:5d058c917599 79
feb11 2:6f3630f5fa06 80 return n;
feb11 0:5d058c917599 81 }
feb11 0:5d058c917599 82
feb11 0:5d058c917599 83 template<size_t T>
feb11 2:6f3630f5fa06 84 uint32_t CircularBuffer<T>::write(uint8_t *data, uint32_t length)
feb11 0:5d058c917599 85 {
feb11 2:6f3630f5fa06 86 uint32_t n = 0;
feb11 3:9a45d6675e65 87 while(n < length && getSize() < T)
feb11 0:5d058c917599 88 {
feb11 0:5d058c917599 89 if(writeIndex == T)
feb11 0:5d058c917599 90 writeIndex = 0;
feb11 2:6f3630f5fa06 91 buffer[writeIndex++] = data[n++];
feb11 0:5d058c917599 92 }
feb11 0:5d058c917599 93
feb11 2:6f3630f5fa06 94 return n;
feb11 2:6f3630f5fa06 95 }
feb11 2:6f3630f5fa06 96
feb11 2:6f3630f5fa06 97 template<size_t T>
feb11 2:6f3630f5fa06 98 uint32_t CircularBuffer<T>::getCapacity() const
feb11 2:6f3630f5fa06 99 {
feb11 2:6f3630f5fa06 100 return T;
feb11 2:6f3630f5fa06 101 }
feb11 2:6f3630f5fa06 102
feb11 2:6f3630f5fa06 103 template<size_t T>
feb11 2:6f3630f5fa06 104 uint32_t CircularBuffer<T>::getSize() const
feb11 2:6f3630f5fa06 105 {
feb11 3:9a45d6675e65 106 return ((writeIndex > readIndex) ? (writeIndex - readIndex) : (T + writeIndex - readIndex));
feb11 3:9a45d6675e65 107 }
feb11 3:9a45d6675e65 108
feb11 3:9a45d6675e65 109 template<size_t T>
feb11 3:9a45d6675e65 110 bool CircularBuffer<T>::isEmpty() const
feb11 3:9a45d6675e65 111 {
feb11 3:9a45d6675e65 112 return getSize() == 0;
feb11 3:9a45d6675e65 113 }
feb11 3:9a45d6675e65 114
feb11 3:9a45d6675e65 115 template<size_t T>
feb11 3:9a45d6675e65 116 bool CircularBuffer<T>::isFull() const
feb11 3:9a45d6675e65 117 {
feb11 3:9a45d6675e65 118 return getSize() == T;
feb11 0:5d058c917599 119 }
feb11 0:5d058c917599 120
feb11 0:5d058c917599 121 typedef CircularBuffer<32> SmallCircularBuffer;
feb11 0:5d058c917599 122 typedef CircularBuffer<128> MediumCircularBuffer;
feb11 2:6f3630f5fa06 123 typedef CircularBuffer<512> BigCircularBuffer;
feb11 0:5d058c917599 124
feb11 0:5d058c917599 125 #endif