recycle.c

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/**
 * @file recycle.c
 * @brief Memory recycling routines for frequently allocated structures.
 *
 * Provides functions that manage pools of reusable memory blocks to
 * reduce malloc overhead and memory fragmentation. Written by Bob
 * Jenkins (September 1996) and released to the public domain with no
 * warranty.
 */
 
#ifndef STANDARD
#  include "standard.h"
#endif
#ifndef RECYCLE
#  include "recycle.h"
#endif
 
reroot *remkroot(size)
  size_t size;
{
  reroot *r = (reroot *)remalloc(sizeof(reroot), "recycle.c, root");
  r->list = (recycle *)0;
  r->trash = (recycle *)0;
  r->size = mdbalign(size);
  r->logsize = RESTART;
  r->numleft = 0;
  return r;
}
 
void refree(r) struct reroot *r;
{
  recycle *temp;
  if ((temp = r->list) != NULL)
    while (r->list) {
      temp = r->list->next;
      free((char *)r->list);
      r->list = temp;
    }
  free((char *)r);
  return;
}
 
/* to be called from the macro renew only */
char *renewx(r) struct reroot *r;
{
  recycle *temp;
  if (r->trash) { /* pull a node off the trash heap */
    temp = r->trash;
    r->trash = temp->next;
    (void)memset((void *)temp, 0, r->size);
  } else { /* allocate a new block of nodes */
    r->numleft = r->size * ((size_t)1 << r->logsize);
    if (r->numleft < REMAX)
      ++r->logsize;
    temp = (recycle *)remalloc(sizeof(recycle) + r->numleft, "recycle.c, data");
    temp->next = r->list;
    r->list = temp;
    r->numleft -= r->size;
    temp = (recycle *)((char *)(r->list + 1) + r->numleft);
  }
  return (char *)temp;
}
 
char *remalloc(len, purpose)
  size_t len;
char *purpose;
{
  char *x = (char *)malloc(len);
  if (!x) {
    fprintf(stderr, "malloc of %d failed for %s\n", (int)len, purpose);
    exit(1);
  }
  return x;
}