Ringbuffer¶
Implements a ringbuffer to maintain past samples in memory for real-time DSP
One of the main goals of the LuckyLoop real-time-process is to calculate phase and power of a specific frequency for a specific channel. To calculate phase and power, we need more than a current sample. To achieve this, data is collected by one of EtherCat slave devices and continually read in the EtherCat main process into a ringbuffer.
Defines
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BUFFERSIZE a sensible default for the buffersize
Functions
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ringbuf *
ringbuf_new(int buffersize) creates a new buffer, returns a pointer to it
- Parameters
buffersize – the size of the ringbuf in samples
- Returns
a new ringbuf
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void
ringbuf_destroy(ringbuf *ringbuffer) destroy a ringbuf and free the allocated memory
- Parameters
ringbuffer – the ringbuf to be destroyed
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int
write_to_buffer(ringbuf *ringbuffer, double sample) writes a new sample into the ringbuff
- Parameters
ringbuffer – the ringbuffer to be written into
sample – a double value written into the the head of the buffer
-
int
write_array_to_buffer(ringbuf *ringbuffer, int chunklen, double *chunk) write an array of samples into the ringbuf
- Parameters
chunk – the array of samples to write into the buffer
chunklen – the size of the array in samples
ringbuffer – the ringbuffer to be written into The last value in the array will be the newest in the ringbuffer
- Returns
int will return 2 if the array is larger than the buffersize, suggesting an overflow
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void
print_rbuf(ringbuf *ringbuffer) print the whole buffer in circular fashion starting at the current head
- Parameters
ringbuffer – the ringbuffer to print
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double
read_ringbuf_pos(ringbuf *ringbuffer, int position) return a sample relative to the current head
- Parameters
ringbuffer – the ringbuffer to read from
position – int the newest value is at 0, the oldest at buffersize-1
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struct
ringbuf - #include <ringbuf.h>
A structure to represent a ringbuffer
Public Members
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double *
buffer the dynamically allocated buffer array
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int
buffersize the size of the buffer in samples
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int
head the current position of the buffer
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double *