malloc/mpool.h

   1 #ifndef MPOOL_H_
   2 #define MPOOL_H_
   3
   4 #include <stdlib.h>
   5 #include <sys/queue.h>
   6
   7 /*#define MP_DEBUG*/
   8 #define MP_STATS
   9
  10 #ifdef MP_DEBUG
  11 #define DPRINTF(a) printf a
  12 #else
  13 #define DPRINTF(a)
  14 #endif
  15
  16 #define MP_NODE_AVAIL  (1 << 0)    /* If not set, node is reserved, else available */
  17 #define MP_NODE_LR     (1 << 1)    /* If not set, node is left buddy, else right buddy */
  18 #define MP_NODE_PARENT (1 << 2)    /* If not set, parent is left buddy, else right buddy */
  19
  20 /* Macro definitions */
  21 #define MPOOL_MARK_AVAIL(pnode) pnode->flags |= MP_NODE_AVAIL
  22 #define MPOOL_MARK_USED(pnode) pnode->flags &= ~MP_NODE_AVAIL
  23 #define MPOOL_MARK_LEFT(pnode) pnode->flags &= ~MP_NODE_LR
  24 #define MPOOL_MARK_RIGHT(pnode) pnode->flags |= MP_NODE_LR
  25
  26 #define MPOOL_IS_AVAIL(pnode) ((pnode->flags & MP_NODE_AVAIL) != 0)
  27 #define MPOOL_IS_USED(pnode)  ((pnode->flags & MP_NODE_AVAIL) == 0)
  28 #define MPOOL_IS_LEFT(pnode)  ((pnode->flags & MP_NODE_LR) == 0)
  29 #define MPOOL_IS_RIGHT(pnode) ((pnode->flags & MP_NODE_LR) != 0)
  30
  31 typedef struct blknode {
  32     unsigned char flags;    /* availability, left-right buddiness, inheritance */
  33     size_t logsize;         /* logarithm of size with base 2 */
  34     void *ptr;              /* pointer to beginning of free block (what mpool_alloc() returns) */
  35     LIST_ENTRY(blknode) next_chunk;
  36 } blknode_t;
  37
  38 typedef struct mpool {
  39     void *mem;
  40     size_t nblocks;       /* nblocks = logsize + 1 */
  41     size_t maxlogsize;    /* logarithm of maximum size of chunk with base 2 */
  42     size_t minlogsize;    /* logarithm of minimum size of chunk with base 2 */
  43 #ifdef MP_STATS
  44     size_t nsplits;       /* number of splits made */
  45     size_t nmerges;       /* number of merges made */
  46 #endif
  47     LIST_HEAD(blkhead, blknode) *blktable;
  48 } mpool_t;
  49
  50 typedef struct blkhead blkhead_t;
  51
  52 typedef enum {
  53     MPOOL_OK,
  54     MPOOL_EBADVAL,
  55     MPOOL_ENOMEM
  56 } mpret_t;
  57
  58 /* Function prototypes */
  59 mpret_t mpool_init(mpool_t **mpool, size_t maxlogsize, size_t minlogsize);
  60 void *mpool_alloc(mpool_t *mpool, size_t blksize);
  61 void mpool_free(mpool_t *mpool, void *ptr);
  62 void mpool_destroy(mpool_t *mpool);
  63
  64 #endif    /* MPOOL_H_ */