malloc/test3.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>  /* for memset() */
   4 #include <time.h>    /* for time() in srand() */
   5
   6 #include "mpool.h"
   7 #include "mstat.h"
   8
   9 #define MAX_BLOCKS 1000
  10
  11 int main(void)
  12 {
  13     char *pblk[MAX_BLOCKS];
  14     mpool_t *mpool;
  15     mpret_t mpret;
  16     size_t an, un;    /* nodes */
  17     size_t ab, ub;    /* blocks */
  18     size_t me, sp;    /* merges, splits */
  19     size_t i, s;
  20
  21     /* Initialize memory pool with 1048576 bytes */
  22     mpret = mpool_init(&mpool, 20, 5);
  23     if (mpret == MPOOL_ENOMEM) {
  24         fprintf(stderr, "mpool: not enough memory\n");
  25         exit(EXIT_FAILURE);
  26     }
  27     else if (mpret == MPOOL_EBADVAL) {
  28         fprintf(stderr, "mpool: bad value passed to mpool_init()\n");
  29         exit(EXIT_FAILURE);
  30     }
  31
  32     /* Initialize random number generator */
  33     srand(time(NULL));
  34
  35     /* Allocate blocks */
  36     for (i = 0; i < MAX_BLOCKS; i++) {
  37         if ((pblk[i] = mpool_alloc(mpool, s = 1 << (5 + rand() % 7))) == NULL)
  38             break;
  39
  40         /*
  41          * Zero out the allocated block
  42          *
  43          * By doing this, there is a chance that we catch
  44          * allocator's bugs, i.e. by writing over the block
  45          * and corrupting next block's header.
  46          */
  47         memset(pblk[i], 0, s);
  48
  49         /* Every now and then free a block to create holes and invoke merges */
  50         if (rand() % 3   == 0) {
  51             mpool_free(mpool, pblk[i]);
  52             pblk[i] = NULL;
  53         }
  54     }
  55
  56     /* Free the rest of the blocks */
  57     for (i = 0; i < MAX_BLOCKS; i++)
  58         if (pblk[i] != NULL)
  59             mpool_free(mpool, pblk[i]);
  60
  61     /* Dump statistics */
  62     mpool_stat_get_nodes(mpool, &an, &un);
  63     mpool_stat_get_bytes(mpool, &ab, &ub);
  64     me = mpool_stat_get_merges(mpool);
  65     sp = mpool_stat_get_splits(mpool);
  66
  67     printf("avail nodes = %-5u\tused nodes = %-5u\tfree(%%) = %.2f\n", an, un, 100.0 * an / (an + un));
  68     printf("avail bytes = %-5u\tused bytes = %-5u\tfree(%%) = %.2f\n", ab, ub, 100.0 * ab / (ab + ub));
  69     printf("splits      = %-5u\tmerges     = %-5u\n", sp, me);
  70
  71     /* Destroy memory pool and free all resources */
  72     mpool_destroy(mpool);
  73
  74     return EXIT_SUCCESS;
  75 }