Small library for using circular buffers (forked from François Berder's implementation in order to add methods and fix problems)
Dependents: CircularBufferTest XBeeApi
Fork of CircularBuffer by
Test suite can be found in this application, CircularBufferTest
CircularBuffer.h@6:242d0e9f13d1, 2014-01-18 (annotated)
- Committer:
- johnb
- Date:
- Sat Jan 18 18:01:03 2014 +0000
- Revision:
- 6:242d0e9f13d1
- Parent:
- 5:abe8909f9603
- Child:
- 7:e2d532183250
Attempt to fix bug whereby getSize() would not return correctly. Previously:; ; char c;; // getSize == 0; x.write( &c, 1 );; // getSize == 1; w.read( &c, 1 );; // getSize() == 512 !
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
feb11 | 0:5d058c917599 | 1 | #ifndef CIRCULAR_BUFFER_H |
feb11 | 0:5d058c917599 | 2 | #define CIRCULAR_BUFFER_H |
feb11 | 0:5d058c917599 | 3 | |
johnb | 5:abe8909f9603 | 4 | #include <cstddef> |
johnb | 5:abe8909f9603 | 5 | #include <stdint.h> |
johnb | 5:abe8909f9603 | 6 | |
feb11 | 4:e15dee1d59ee | 7 | /** This class implements a static circular buffer. |
johnb | 5:abe8909f9603 | 8 | |
johnb | 5:abe8909f9603 | 9 | CirularBuffer class originally by François Berder ( see http://mbed.org/users/feb11/code/CircularBuffer/ ) |
johnb | 5:abe8909f9603 | 10 | Additions by John Bailey ( http://mbed.org/users/johnb/ ) |
feb11 | 4:e15dee1d59ee | 11 | */ |
feb11 | 0:5d058c917599 | 12 | template<size_t T> |
feb11 | 0:5d058c917599 | 13 | class CircularBuffer |
feb11 | 0:5d058c917599 | 14 | { |
feb11 | 0:5d058c917599 | 15 | public : |
johnb | 5:abe8909f9603 | 16 | |
feb11 | 4:e15dee1d59ee | 17 | /** Default constructor |
feb11 | 4:e15dee1d59ee | 18 | */ |
feb11 | 0:5d058c917599 | 19 | CircularBuffer(); |
feb11 | 0:5d058c917599 | 20 | |
johnb | 5:abe8909f9603 | 21 | /** Reads data from buffer (data is removed from the buffer as |
johnb | 5:abe8909f9603 | 22 | opposed to the peek method which allows inspection of the |
johnb | 5:abe8909f9603 | 23 | contents without modifying the buffer) |
feb11 | 4:e15dee1d59ee | 24 | |
feb11 | 4:e15dee1d59ee | 25 | \param data output buffer |
feb11 | 4:e15dee1d59ee | 26 | \param length Maximum number of bytes to read |
feb11 | 4:e15dee1d59ee | 27 | \return Number of bytes read |
feb11 | 4:e15dee1d59ee | 28 | |
feb11 | 4:e15dee1d59ee | 29 | \note The return value cannot exceed max(length,capacity) |
feb11 | 4:e15dee1d59ee | 30 | */ |
feb11 | 2:6f3630f5fa06 | 31 | uint32_t read(uint8_t *data, uint32_t length); |
johnb | 5:abe8909f9603 | 32 | |
johnb | 5:abe8909f9603 | 33 | /** Reads data from buffer leaving the data in the buffer |
johnb | 5:abe8909f9603 | 34 | (as opposed to the read method which removed the returned |
johnb | 5:abe8909f9603 | 35 | data from the buffer) |
johnb | 5:abe8909f9603 | 36 | |
johnb | 5:abe8909f9603 | 37 | \param data output buffer |
johnb | 5:abe8909f9603 | 38 | \param length Maximum number of bytes to read |
johnb | 5:abe8909f9603 | 39 | \return Number of bytes read |
johnb | 5:abe8909f9603 | 40 | |
johnb | 5:abe8909f9603 | 41 | \note The return value cannot exceed max(length,capacity) |
johnb | 5:abe8909f9603 | 42 | */ |
johnb | 5:abe8909f9603 | 43 | uint32_t peek(uint8_t *data, uint32_t length) const; |
feb11 | 4:e15dee1d59ee | 44 | |
feb11 | 4:e15dee1d59ee | 45 | /** Writes data in buffer |
feb11 | 4:e15dee1d59ee | 46 | |
feb11 | 4:e15dee1d59ee | 47 | \param data input buffer |
feb11 | 4:e15dee1d59ee | 48 | \param length Maximum number of bytes to write |
feb11 | 4:e15dee1d59ee | 49 | \return Number of bytes wrote |
feb11 | 4:e15dee1d59ee | 50 | |
feb11 | 4:e15dee1d59ee | 51 | \note The return value cannot exceed max(length,capacity) |
feb11 | 4:e15dee1d59ee | 52 | */ |
feb11 | 2:6f3630f5fa06 | 53 | uint32_t write(uint8_t *data, uint32_t length); |
feb11 | 3:9a45d6675e65 | 54 | |
feb11 | 4:e15dee1d59ee | 55 | /** Returns the total capacity of this buffer |
feb11 | 4:e15dee1d59ee | 56 | \return Capacity of buffer |
feb11 | 4:e15dee1d59ee | 57 | */ |
feb11 | 2:6f3630f5fa06 | 58 | uint32_t getCapacity() const; |
feb11 | 4:e15dee1d59ee | 59 | |
feb11 | 4:e15dee1d59ee | 60 | /** Returns the number of bytes available in the buffer |
feb11 | 4:e15dee1d59ee | 61 | \return Number of bytes available in the buffer |
feb11 | 4:e15dee1d59ee | 62 | */ |
feb11 | 3:9a45d6675e65 | 63 | uint32_t getSize() const; |
feb11 | 4:e15dee1d59ee | 64 | |
feb11 | 4:e15dee1d59ee | 65 | /** Checks if this buffer is empty |
feb11 | 4:e15dee1d59ee | 66 | \return True if the buffer is empty, false otherwise |
feb11 | 4:e15dee1d59ee | 67 | */ |
feb11 | 3:9a45d6675e65 | 68 | bool isEmpty() const; |
feb11 | 4:e15dee1d59ee | 69 | |
feb11 | 4:e15dee1d59ee | 70 | /** Checks if this buffer is full |
feb11 | 4:e15dee1d59ee | 71 | \return True if the buffer is full, false otherwise |
feb11 | 4:e15dee1d59ee | 72 | */ |
feb11 | 3:9a45d6675e65 | 73 | bool isFull() const; |
feb11 | 2:6f3630f5fa06 | 74 | |
feb11 | 0:5d058c917599 | 75 | private : |
johnb | 5:abe8909f9603 | 76 | |
johnb | 5:abe8909f9603 | 77 | typedef uint16_t CircularBufferIndex_t; |
feb11 | 0:5d058c917599 | 78 | |
johnb | 5:abe8909f9603 | 79 | CircularBufferIndex_t readIndex, writeIndex; |
feb11 | 0:5d058c917599 | 80 | uint8_t buffer[T]; |
feb11 | 0:5d058c917599 | 81 | |
feb11 | 0:5d058c917599 | 82 | }; |
feb11 | 0:5d058c917599 | 83 | |
feb11 | 0:5d058c917599 | 84 | template<size_t T> |
feb11 | 0:5d058c917599 | 85 | CircularBuffer<T>::CircularBuffer(): |
johnb | 6:242d0e9f13d1 | 86 | readIndex(0), |
feb11 | 1:9953890d59e2 | 87 | writeIndex(0) |
feb11 | 0:5d058c917599 | 88 | { |
feb11 | 0:5d058c917599 | 89 | } |
feb11 | 0:5d058c917599 | 90 | |
feb11 | 0:5d058c917599 | 91 | template<size_t T> |
feb11 | 2:6f3630f5fa06 | 92 | uint32_t CircularBuffer<T>::read(uint8_t *data, uint32_t length) |
feb11 | 0:5d058c917599 | 93 | { |
feb11 | 2:6f3630f5fa06 | 94 | uint32_t n = 0; |
feb11 | 3:9a45d6675e65 | 95 | while(n < length && getSize() > 0) |
feb11 | 0:5d058c917599 | 96 | { |
feb11 | 2:6f3630f5fa06 | 97 | if(readIndex == T) |
feb11 | 2:6f3630f5fa06 | 98 | readIndex = 0; |
feb11 | 2:6f3630f5fa06 | 99 | data[n++] = buffer[readIndex++]; |
feb11 | 0:5d058c917599 | 100 | } |
feb11 | 0:5d058c917599 | 101 | |
feb11 | 2:6f3630f5fa06 | 102 | return n; |
feb11 | 0:5d058c917599 | 103 | } |
feb11 | 0:5d058c917599 | 104 | |
feb11 | 0:5d058c917599 | 105 | template<size_t T> |
johnb | 5:abe8909f9603 | 106 | uint32_t CircularBuffer<T>::peek(uint8_t *data, uint32_t length) const |
johnb | 5:abe8909f9603 | 107 | { |
johnb | 5:abe8909f9603 | 108 | uint32_t n = 0; |
johnb | 5:abe8909f9603 | 109 | CircularBufferIndex_t src = readIndex; |
johnb | 5:abe8909f9603 | 110 | while(n < length && getSize() > 0) |
johnb | 5:abe8909f9603 | 111 | { |
johnb | 5:abe8909f9603 | 112 | if(src == T) { |
johnb | 5:abe8909f9603 | 113 | src = 0; |
johnb | 5:abe8909f9603 | 114 | } |
johnb | 5:abe8909f9603 | 115 | data[n++] = buffer[src++]; |
johnb | 5:abe8909f9603 | 116 | } |
johnb | 5:abe8909f9603 | 117 | |
johnb | 5:abe8909f9603 | 118 | return n; |
johnb | 5:abe8909f9603 | 119 | } |
johnb | 5:abe8909f9603 | 120 | |
johnb | 5:abe8909f9603 | 121 | template<size_t T> |
feb11 | 2:6f3630f5fa06 | 122 | uint32_t CircularBuffer<T>::write(uint8_t *data, uint32_t length) |
feb11 | 0:5d058c917599 | 123 | { |
feb11 | 2:6f3630f5fa06 | 124 | uint32_t n = 0; |
feb11 | 3:9a45d6675e65 | 125 | while(n < length && getSize() < T) |
feb11 | 0:5d058c917599 | 126 | { |
feb11 | 0:5d058c917599 | 127 | if(writeIndex == T) |
feb11 | 0:5d058c917599 | 128 | writeIndex = 0; |
feb11 | 2:6f3630f5fa06 | 129 | buffer[writeIndex++] = data[n++]; |
feb11 | 0:5d058c917599 | 130 | } |
feb11 | 0:5d058c917599 | 131 | |
feb11 | 2:6f3630f5fa06 | 132 | return n; |
feb11 | 2:6f3630f5fa06 | 133 | } |
feb11 | 2:6f3630f5fa06 | 134 | |
feb11 | 2:6f3630f5fa06 | 135 | template<size_t T> |
feb11 | 2:6f3630f5fa06 | 136 | uint32_t CircularBuffer<T>::getCapacity() const |
feb11 | 2:6f3630f5fa06 | 137 | { |
feb11 | 2:6f3630f5fa06 | 138 | return T; |
feb11 | 2:6f3630f5fa06 | 139 | } |
feb11 | 2:6f3630f5fa06 | 140 | |
feb11 | 2:6f3630f5fa06 | 141 | template<size_t T> |
feb11 | 2:6f3630f5fa06 | 142 | uint32_t CircularBuffer<T>::getSize() const |
feb11 | 2:6f3630f5fa06 | 143 | { |
johnb | 6:242d0e9f13d1 | 144 | return ((writeIndex >= readIndex) ? (writeIndex - readIndex) : (T + writeIndex - readIndex)); |
feb11 | 3:9a45d6675e65 | 145 | } |
feb11 | 3:9a45d6675e65 | 146 | |
feb11 | 3:9a45d6675e65 | 147 | template<size_t T> |
feb11 | 3:9a45d6675e65 | 148 | bool CircularBuffer<T>::isEmpty() const |
feb11 | 3:9a45d6675e65 | 149 | { |
feb11 | 3:9a45d6675e65 | 150 | return getSize() == 0; |
feb11 | 3:9a45d6675e65 | 151 | } |
feb11 | 3:9a45d6675e65 | 152 | |
feb11 | 3:9a45d6675e65 | 153 | template<size_t T> |
feb11 | 3:9a45d6675e65 | 154 | bool CircularBuffer<T>::isFull() const |
feb11 | 3:9a45d6675e65 | 155 | { |
feb11 | 3:9a45d6675e65 | 156 | return getSize() == T; |
feb11 | 0:5d058c917599 | 157 | } |
feb11 | 0:5d058c917599 | 158 | |
feb11 | 0:5d058c917599 | 159 | typedef CircularBuffer<32> SmallCircularBuffer; |
feb11 | 0:5d058c917599 | 160 | typedef CircularBuffer<128> MediumCircularBuffer; |
feb11 | 2:6f3630f5fa06 | 161 | typedef CircularBuffer<512> BigCircularBuffer; |
feb11 | 0:5d058c917599 | 162 | |
feb11 | 0:5d058c917599 | 163 | #endif |