Nils O. Selåsdal
67 lines
1.8 KiB
C
67 lines
1.8 KiB
C
#ifndef LPOOL_H_
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#define LPOOL_H_
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#include <stddef.h>
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef union LPoolBlock LPoolBlock;
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union LPoolBlock {
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uint32_t next; // offset from start to next free block (when not allocated)
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unsigned char data[0]; // data when allocated
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};
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/** @file
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* Pool allocator.
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*
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* An LPool allocates fixed size memory chunks from a provided buffer,
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* and memory allocations can be free'd in any order.
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*
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* The backing array should be suitable aligned to the types
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* that will be allocated from it. Use .e.g
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* @code
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* _Alignas(16) char mem[1024];
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* @endcode
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* as the backing buffer.
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*
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*/
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typedef struct LPool LPool;
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struct LPool {
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LPoolBlock *free_list; // free list
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uint8_t *start; // start of user buffer
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uint8_t *end; // one past end of user buffer
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uint32_t block_size; // aligned size of each block
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uint32_t capacity; // number of blocks
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uint32_t align; // alignment
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};
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/** Initialize the pool.
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*
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* Block size will be rounded up by alignment, or to size of a pointer if alignment is less that a pointer.
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* Prefer to use lock sizes that's pointer aligned
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*
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* @param buffer backing buffer for the pool
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* @param buffer_size size of @buffer
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* @param block_size size of each allocation.
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* @param alignment alignment of each block (must be power of 2)
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*/
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void lpool_init(LPool *pool, void *buffer, size_t buffer_size, uint32_t block_size, uint32_t alignment);
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// Allocate a block from the pool. Returns NULL if no more space
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[[gnu::assume_aligned(_Alignof(LPoolBlock))]]
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void *lpool_alloc(LPool *pool);
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// Free @p . Returns memory to the pool
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void lpool_free(LPool *pool, void *p);
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// Frees all memory in the pool, resetting it to initial state.
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void lpool_reset(LPool *pool);
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#ifdef __cplusplus
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} // extern "C"
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#endif
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#endif
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