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#pragma once
#include <assert.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
/// Define a typed mempool of the given number of blocks.
#define DEF_MEMPOOL(POOL, TYPE, NUM_BLOCKS) \
typedef struct POOL { \
mempool pool; \
BlockInfo block_info[NUM_BLOCKS]; \
TYPE blocks[NUM_BLOCKS]; \
} POOL;
/// Create a new pool.
#define mempool_make(POOL) \
{ \
assert(POOL); \
const size_t block_size = sizeof((POOL)->blocks[0]); \
const size_t num_blocks = sizeof((POOL)->blocks) / block_size; \
mempool_make_(&(POOL)->pool, (POOL)->block_info, (POOL)->blocks, \
num_blocks, block_size); \
}
/// Allocate a new block.
/// Return 0 if there is no memory left.
#define mempool_alloc(POOL) mempool_alloc_(&(POOL)->pool)
/// Free the block.
/// The block pointer is conveniently set to 0.
#define mempool_free(POOL, BLOCK_PTR) \
assert(*BLOCK_PTR); \
mempool_free_(&(POOL)->pool, (void**)BLOCK_PTR)
/// Return the ith block.
/// The block must have been allocated.
#define mempool_get_block(POOL, INDEX) \
((typeof((POOL)->blocks[0])*)mempool_get_block_(&(POOL)->pool, INDEX))
/// Get the index to the given block.
#define mempool_get_block_index(POOL, BLOCK_PTR) \
mempool_get_block_index_(&(POOL)->pool, BLOCK_PTR)
/// Iterate over the used blocks of the pool.
#define mempool_foreach(POOL, ITER, BODY) \
for (size_t i = 0; \
i < (sizeof((POOL)->blocks) / sizeof(typeof((POOL)->blocks[0]))); \
++i) { \
if (!(POOL)->block_info[i].used) { \
continue; \
} \
typeof((POOL)->blocks[0])* ITER = &(POOL)->blocks[i]; \
(void)ITER; \
BODY; \
}
typedef struct BlockInfo {
bool used;
} BlockInfo;
typedef struct mempool {
size_t block_size_bytes;
size_t num_blocks;
size_t next_free_block;
bool full;
BlockInfo* block_info;
uint8_t* blocks;
} mempool;
/// Create a pool allocator from user-provided memory.
/// `BlockInfo` must hold at least `num_blocks` entries.
/// `blocks` must be at least `num_blocks` * `block_size_bytes` bytes.
/// All blocks are zeroed out for convenience.
void mempool_make_(mempool*, BlockInfo*, void* blocks, size_t num_blocks,
size_t block_size_bytes);
/// Allocate a new block.
/// Return 0 if there is no memory left.
void* mempool_alloc_(mempool*);
/// Free the block.
/// The block pointer is conveniently set to 0.
void mempool_free_(mempool*, void** block_ptr);
/// Return the ith block.
/// The block must have been allocated.
void* mempool_get_block_(const mempool*, size_t block_index);
/// Get the index to the given block.
size_t mempool_get_block_index_(const mempool*, const void* block);
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