ringbuffer.h

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#pragma once
 
// C11 stdatomic.h conflicts with MSVC's C++ <atomic> header on Windows.
// atomic_t is always defined in ascii-chat/atomic.h (wraps C11 _Atomic)
#include <ascii-chat/atomic.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include "platform/mutex.h"
#include "util/magic.h"
 
typedef struct {
  char *buffer;
  size_t element_size;
  size_t capacity;
  atomic_t head;
  atomic_t tail;
  atomic_t size;
  bool is_power_of_two;
  size_t capacity_mask;
} ringbuffer_t;
 
/* ============================================================================
 * Audio Ring Buffer - Simple ring buffer for audio samples
 * ============================================================================
 */
 
#define AUDIO_RING_BUFFER_SIZE 192000
 
#define AUDIO_JITTER_BUFFER_THRESHOLD 4800
 
#define AUDIO_JITTER_LOW_WATER_MARK 2400
 
#define AUDIO_JITTER_HIGH_WATER_MARK (AUDIO_JITTER_BUFFER_THRESHOLD * 2)
 
#define AUDIO_JITTER_TARGET_LEVEL (AUDIO_JITTER_BUFFER_THRESHOLD + 480)
 
#define AUDIO_CROSSFADE_SAMPLES 256
 
typedef struct audio_ring_buffer {
  float data[AUDIO_RING_BUFFER_SIZE];
  atomic_t write_index;
  atomic_t read_index;
  atomic_t discard_pending;
  atomic_t discard_to_index;
  atomic_t jitter_buffer_filled;
  atomic_t crossfade_samples_remaining;
  atomic_t crossfade_fade_in;
  float last_sample;
  atomic_t underrun_count;
  bool jitter_buffer_enabled;
  mutex_t mutex;
} audio_ring_buffer_t;
 
/* ============================================================================
 * Ring Buffer API
 * ============================================================================
 */
 
ringbuffer_t *ringbuffer_create(size_t element_size, size_t capacity);
 
void ringbuffer_destroy(ringbuffer_t *rb);
 
bool ringbuffer_write(ringbuffer_t *rb, const void *data);
 
bool ringbuffer_read(ringbuffer_t *rb, void *data);
 
bool ringbuffer_peek(ringbuffer_t *rb, void *data);
 
size_t ringbuffer_size(const ringbuffer_t *rb);
 
bool ringbuffer_is_empty(const ringbuffer_t *rb);
 
bool ringbuffer_is_full(const ringbuffer_t *rb);
 
void ringbuffer_clear(ringbuffer_t *rb);
 
/* ============================================================================
 * Frame Buffer Specific
 * ============================================================================
 */
 
typedef struct {
  uint64_t magic;
  size_t size;
  char *data;
} frame_t;
 
typedef struct {
  uint64_t magic;
  char source_client_id[64];
  uint32_t frame_sequence;
  uint32_t timestamp;
  size_t size;
  char *data;
} multi_source_frame_t;
 
#define FRAME_MAGIC MAGIC_FRAME_VALID
#define FRAME_FREED MAGIC_FRAME_FREED
 
typedef struct {
  ringbuffer_t *rb;
  mutex_t mutex;
} framebuffer_t;
 
framebuffer_t *framebuffer_create(size_t capacity);
 
framebuffer_t *framebuffer_create_multi(size_t capacity);
 
void framebuffer_destroy(framebuffer_t *fb);
 
bool framebuffer_write_frame(framebuffer_t *fb, const char *frame_data, size_t frame_size);
 
bool framebuffer_read_frame(framebuffer_t *fb, frame_t *frame);
 
void framebuffer_clear(framebuffer_t *fb);
 
bool framebuffer_write_multi_frame(framebuffer_t *fb, const char *frame_data, size_t frame_size,
                                   uint32_t source_client_id, uint32_t frame_sequence, uint32_t timestamp);
 
bool framebuffer_read_multi_frame(framebuffer_t *fb, multi_source_frame_t *frame);
 
bool framebuffer_peek_latest_multi_frame(framebuffer_t *fb, multi_source_frame_t *frame);