CircularBuffer
The CircularBuffer class provides APIs to push and pop data from a buffer. You should check if the buffer is full before pushing the data because a full buffer overwrites the data. The empty API is available to check contents in buffer before performing the pop operation.
CircularBuffer class is interrupt safe; all data operations are performed inside the critical section.
CircularBuffer is a templated class supporting different datatypes. The declaration of the CircularBuffer class must specify datatype and buffer size.
Memory considerations
The actual data buffer is allocated as part of the CircularBuffer object memory.
Declaration example
This is an example of BUF_SIZE long integer CircularBuffer:
CircularBuffer<int, BUF_SIZE> buf;
CircularBuffer class reference
| Public Member Functions | |
| void | push (const T &data) |
| Push the transaction to the buffer. More... | |
| void | push (const T *src, CounterType len) |
| Push the transaction to the buffer. More... | |
| void | push (mbed::Span< const T > src) |
| Push the transaction to the buffer. More... | |
| bool | pop (T &data) |
| Pop from the buffer. More... | |
| CounterType | pop (T *dest, CounterType len) |
| Pop multiple elements from the buffer. More... | |
| mbed::Span< T > | pop (mbed::Span< T > dest) |
| Pop multiple elements from the buffer. More... | |
| bool | empty () const |
| Check if the buffer is empty. More... | |
| bool | full () const |
| Check if the buffer is full. More... | |
| void | reset () |
| Reset the buffer. More... | |
| CounterType | size () const |
| Get the number of elements currently stored in the circular_buffer. More... | |
| bool | peek (T &data) const |
| Peek into circular buffer without popping. More... | |
CircularBuffer example
/*
* Copyright (c) 2017 - 2020 Arm Limited and affiliates.
* SPDX-License-Identifier: Apache-2.0
*/
#include "mbed.h"
#include "platform/CircularBuffer.h"
#define BUF_SIZE 10
CircularBuffer<char, BUF_SIZE> buf;
char data_stream[] = "DataToBeAddedToBuffer";
int main()
{
uint32_t bytes_written = 0;
while (!buf.full()) {
buf.push(data_stream[bytes_written++]);
}
printf("Circular buffer is full: \"%s\" or empty: \"%s\" \n",
(buf.full() ? "true" : "false"),
(buf.empty() ? "true" : "false"));
printf("Bytes written %ld \n", bytes_written);
// If buffer is full, contents will be over-written
buf.push(data_stream[bytes_written++]);
char data = 0;
printf("Buffer contents: ");
while (!buf.empty()) {
buf.pop(data);
printf("%c", data);
}
printf("\n");
printf("Circular buffer is full: \"%s\" or empty: \"%s\" \n",
(buf.full() ? "true" : "false"),
(buf.empty() ? "true" : "false"));
return 0;
}