#ifndef _TOKU_MEMPOOL_H
#define _TOKU_MEMPOOL_H

#ident "Copyright (c) 2007 Tokutek Inc.  All rights reserved."

/* a memory pool is a contiguous region of memory that supports single
   allocations from the pool.  these allocated regions are never recycled.
   when the memory pool no longer has free space, the allocated chunks 
   must be relocated by the application to a new memory pool. */ 

#include <sys/types.h>

struct mempool;

struct mempool {
    void *base;           /* the base address of the memory */
    size_t free_offset;      /* the offset of the memory pool free space */
    size_t size;             /* the size of the memory */
    size_t frag_size;        /* the size of the fragmented memory */
};

/* initialize the memory pool with the base address and size of a
   contiguous chunk of memory */
void toku_mempool_init(struct mempool *mp, void *base, size_t size);

/* finalize the memory pool */
void toku_mempool_fini(struct mempool *mp);

/* get the base address of the memory pool */
void *toku_mempool_get_base(struct mempool *mp);

/* get the size of the memory pool */
size_t toku_mempool_get_size(struct mempool *mp);

/* get the amount of fragmented space in the memory pool */
size_t toku_mempool_get_frag_size(struct mempool *mp);

/* allocate a chunk of memory from the memory pool suitably aligned */
void *toku_mempool_malloc(struct mempool *mp, size_t size, int alignment);

/* free a previously allocated chunk of memory.  the free only updates
   a count of the amount of free space in the memory pool.  the memory
   pool does not keep track of the locations of the free chunks */
void toku_mempool_mfree(struct mempool *mp, void *vp, size_t size);

/* verify that a memory range is contained within a mempool */
static inline int toku_mempool_inrange(struct mempool *mp, void *vp, size_t size) {
    return (mp->base <= vp) && ((char *)vp + size <= (char *)mp->base + mp->size);
}

#endif
