Ring Buffer Module (C)

A lightweight, statically allocated ring (circular) buffer implementation in C, designed for embedded systems. This module is thread- and ISR-safe via optional locking hooks.

Features

• Fixed-size buffer with user-defined capacity
• Single-byte and multi-byte read/write APIs
• Optional lock/unlock hooks for safe access in concurrent environments
• Support for buffer peek, reset, and size queries
• Minimal dependencies (<stdint.h> only)

Files

• ring_buffer.h – Header file with API declarations and ring_buffer_t structure
• ring_buffer.c – Implementation of all ring buffer functions

Usage

Initialization

ring_buffer_t rb;
ring_buffer_init(&rb);

(Optional) Thread/ISR-Safety

You can provide locking hooks to ensure atomic operations:

void lock_fn(void) { __disable_irq(); }
void unlock_fn(void) { __enable_irq(); }

ring_buffer_set_lock_hooks(&rb, lock_fn, unlock_fn);

Writing to the Buffer

ring_buffer_put(&rb, 0x55); // Write one byte

uint8_t data[] = {1, 2, 3};
ring_buffer_write(&rb, data, sizeof(data)); // Write multiple bytes

Reading from the Buffer

uint8_t byte;
if (ring_buffer_get(&rb, &byte)) {
    // byte contains valid data
}

uint8_t out[3];
ring_buffer_read(&rb, out, 3); // Read up to 3 bytes

Peek and Status

uint8_t peeked;
ring_buffer_peek(&rb, &peeked); // Peek next byte without removing

ring_buffer_is_empty(&rb);
ring_buffer_is_full(&rb);
ring_buffer_size(&rb);

Resetting

ring_buffer_reset(&rb); // Clears buffer

Configuration

• Maximum size is defined in ring_buffer.h:

  #define RING_BUFFER_MAX_SIZE (256)