ring-buffer v0.1.0

Fixed-size byte ring buffer with explicit full and empty results.

Application scenarios

• A UART receive ISR pushes bytes and the main loop pops them.
• An IR capture queue stores edge timestamps before decoding.
• A logger keeps the last N events without allocation.

Contract

void ring_buffer_init(ring_buffer_t *buffer, uint8_t *data, uint16_t size);
uint8_t ring_buffer_push(ring_buffer_t *buffer, uint8_t value);
uint8_t ring_buffer_pop(ring_buffer_t *buffer, uint8_t *value);
uint16_t ring_buffer_count(const ring_buffer_t *buffer);
uint8_t ring_buffer_full(const ring_buffer_t *buffer);
uint8_t ring_buffer_empty(const ring_buffer_t *buffer);
void ring_buffer_clear(ring_buffer_t *buffer);

• Caller owns data; size must be at least 1.
• push returns 0 when full; pop returns 0 when empty.
• Drop-newest on full; the caller can choose a different policy.
• No allocation.

Parameters

• size: worst-case burst plus main-loop latency.
• Memory is 2*size bytes plus 12 bytes of state.

Memory and timing

• O(1) push/pop; no locks.
• Single producer and single consumer are safe when each owns one index.

Integration

uint8_t storage[64];
ring_buffer_t rx;
ring_buffer_init(&rx, storage, sizeof(storage));
/* ISR: */ ring_buffer_push(&rx, byte);
/* main: */ while (ring_buffer_pop(&rx, &byte)) { handle(byte); }

When not to use

• Multiple producers without a critical section.
• Variable-size records; use a byte stream plus a frame parser.

Verification

make test covers wrap, full, empty, count, clear, and size 0.

uint8_t *data;
uint16_t size;
uint16_t read;
uint16_t write;
uint16_t count;