buffer_pool.h

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#pragma once
 
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <ascii-chat/atomic.h>
#include "platform/mutex.h"
#include "util/magic.h"
 
/* ============================================================================
 * Configuration Constants
 * ============================================================================
 */
 
#define BUFFER_POOL_MAX_BYTES (337 * 1024 * 1024)
 
#define BUFFER_POOL_SHRINK_DELAY_NS 5000000000ULL
 
#define BUFFER_POOL_MIN_SIZE 64
 
#define BUFFER_POOL_MAX_SINGLE_SIZE (4 * 1024 * 1024)
 
#define BUFFER_POOL_MAGIC MAGIC_BUFFER_POOL_VALID
#define BUFFER_POOL_MAGIC_FALLBACK MAGIC_BUFFER_POOL_FALLBACK
 
/* ============================================================================
 * Data Structures
 * ============================================================================
 */
 
typedef struct buffer_node {
  uint32_t magic;                         
  uint32_t _pad;                          
  size_t size;                            
  atomic_ptr_t next;                      
  atomic_t returned_at_ns;                
  struct buffer_pool *pool;               
} buffer_node_t;
 
typedef struct buffer_pool {
  atomic_ptr_t free_list;                 
  mutex_t shrink_mutex;                   
 
  size_t max_bytes;         
  uint64_t shrink_delay_ns; 
 
  atomic_t current_bytes;   
  atomic_t used_bytes;      
  atomic_t peak_bytes;      
  atomic_t peak_pool_bytes; 
 
  atomic_t hits;             
  atomic_t allocs;           
  atomic_t returns;          
  atomic_t shrink_freed;     
  atomic_t malloc_fallbacks; 
} buffer_pool_t;
 
/* ============================================================================
 * Buffer Pool API
 * ============================================================================
 */
 
buffer_pool_t *buffer_pool_create(size_t max_bytes, uint64_t shrink_delay_ns);
 
void buffer_pool_destroy(buffer_pool_t *pool);
 
void *buffer_pool_alloc(buffer_pool_t *pool, size_t size);
 
void buffer_pool_free(buffer_pool_t *pool, const void *data, size_t size);
 
void buffer_pool_shrink(buffer_pool_t *pool);
 
void buffer_pool_get_stats(buffer_pool_t *pool, size_t *current_bytes, size_t *used_bytes, size_t *free_bytes);
 
void buffer_pool_log_stats(buffer_pool_t *pool, const char *name);
 
/* ============================================================================
 * Global Buffer Pool
 * ============================================================================
 */
 
void buffer_pool_init_global(void);
void buffer_pool_cleanup_global(void);
buffer_pool_t *buffer_pool_get_global(void);
 
/* ============================================================================
 * Convenience Macros
 * ============================================================================
 */
 
#define POOL_ALLOC(size) buffer_pool_alloc(NULL, (size))
#define POOL_FREE(data, size) buffer_pool_free(NULL, (data), (size))