File syn_pingpong.h¶

FileList > src > syntropic > util > syn_pingpong.h

Ping-pong (double) buffer — header-only, zero-copy DMA pattern. More...

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

Classes¶

Type	Name
struct	SYN_PingPong Ping-pong (double) buffer — zero-copy DMA pattern.

Public Static Functions¶

Type	Name
uint8_t *	syn_pingpong_active (const SYN_PingPong * pp) Get pointer to the active (being-filled) buffer.
void	syn_pingpong_consume (SYN_PingPong * pp) Mark the ready buffer as consumed. Call after processing.
void	syn_pingpong_init (SYN_PingPong * pp, uint8_t * buf_a, uint8_t * buf_b, size_t size) Initialize with two user-provided buffers of equal size.
bool	syn_pingpong_ready (const SYN_PingPong * pp) Check if the ready buffer has unprocessed data.
uint8_t *	syn_pingpong_ready_buf (const SYN_PingPong * pp) Get pointer to the ready (available-for-reading) buffer.
size_t	syn_pingpong_size (const SYN_PingPong * pp) Get the buffer size.
void	syn_pingpong_swap (SYN_PingPong * pp) Swap buffers. Call from ISR/DMA complete.

Detailed Description¶

One buffer is "active" (being filled by DMA/ISR), the other is "ready" (available for processing). Call swap() when the active buffer is full to exchange them atomically.

** **

uint8_t pool_a[256], pool_b[256];
SYN_PingPong pp;
syn_pingpong_init(&pp, pool_a, pool_b, 256);

// DMA writes into active buffer:
uint8_t *dma_buf = syn_pingpong_active(&pp);
start_dma(dma_buf, 256);

// DMA complete ISR:
syn_pingpong_swap(&pp);

// Main loop processes the ready buffer:
if (syn_pingpong_ready(&pp)) {
    uint8_t *data = syn_pingpong_ready_buf(&pp);
    process(data, 256);
    syn_pingpong_consume(&pp);
}

Public Static Functions Documentation¶

function syn_pingpong_active¶

Get pointer to the active (being-filled) buffer.

static inline uint8_t * syn_pingpong_active (
    const SYN_PingPong * pp
)

Parameters:

pp Ping-pong instance.

Returns:

Active buffer pointer.

function syn_pingpong_consume¶

Mark the ready buffer as consumed. Call after processing.

static inline void syn_pingpong_consume (
    SYN_PingPong * pp
)

Parameters:

pp Ping-pong instance.

function syn_pingpong_init¶

Initialize with two user-provided buffers of equal size.

static inline void syn_pingpong_init (
    SYN_PingPong * pp,
    uint8_t * buf_a,
    uint8_t * buf_b,
    size_t size
)

Parameters:

pp Ping-pong instance.
buf_a First buffer.
buf_b Second buffer.
size Size of each buffer in bytes.

function syn_pingpong_ready¶

Check if the ready buffer has unprocessed data.

static inline bool syn_pingpong_ready (
    const SYN_PingPong * pp
)

Parameters:

pp Ping-pong instance.

Returns:

true if data is ready.

function syn_pingpong_ready_buf¶

Get pointer to the ready (available-for-reading) buffer.

static inline uint8_t * syn_pingpong_ready_buf (
    const SYN_PingPong * pp
)

Parameters:

pp Ping-pong instance.

Returns:

Ready buffer pointer.

function syn_pingpong_size¶

Get the buffer size.

static inline size_t syn_pingpong_size (
    const SYN_PingPong * pp
)

Parameters:

pp Ping-pong instance.

Returns:

Buffer size in bytes.

function syn_pingpong_swap¶

Swap buffers. Call from ISR/DMA complete.

static inline void syn_pingpong_swap (
    SYN_PingPong * pp
)

The previously-active buffer becomes ready for processing. The previously-ready buffer becomes the new active buffer.

Parameters:

pp Ping-pong instance.

The documentation for this class was generated from the following file src/syntropic/util/syn_pingpong.h