示例#1
0
void *tmalloc(unsigned nbytes)
{
  CHUNK *p;
  unsigned size;

  if (bot == NULL)
    init();

  size = sizeof(CHUNK) * ((nbytes+sizeof(CHUNK)-1)/sizeof(CHUNK) + 1);

  for (p = bot; p != NULL; p = RIGHT(p))
    if (GET_FREEBIT(p) && CHUNKSIZE(p) >= size)
      break;
  if (p == NULL)
    return NULL;
  
  if (CHUNKSIZE(p) > size)      /* create a remainder chunk */
    {
      CHUNK *q, *pr;

      CLR_FREEBIT(p);           /* required for pointer manipulation */
      q = (CHUNK *)((char *)p + CHUNKSIZE(p) - size);
      pr = p->s.r;
      q->s.l = p; q->s.r = pr;
      p->s.r = q; pr->s.l = q;
      SET_FREEBIT(p);

      p = q;                    /* return q, not the remainder */
    }

  CLR_FREEBIT(p);   //what's going on here?
  return FROMCHUNK(p);
}
示例#2
0
文件: tmalloc.c 项目: billyue/Shady
void *tmalloc(unsigned nbytes)
{
  CHUNK *p;
  unsigned size;

  if (bot == NULL)
    init();

  size = sizeof(CHUNK) * ((nbytes+sizeof(CHUNK)-1)/sizeof(CHUNK) + 1);

  for (p = bot; p != NULL; p = RIGHT(p))
    if (GET_FREEBIT(p) && CHUNKSIZE(p) >= size)
      break;
  if (p == NULL)
    return NULL;

  CLR_FREEBIT(p);
  if (CHUNKSIZE(p) > size)      /* create a remainder chunk */
    {
      CHUNK *q, *pr;
      q = (CHUNK *)(size + (char *)p);
      pr = p->s.r;
      q->s.l = p; q->s.r = pr;
      p->s.r = q; pr->s.l = q;
      SET_FREEBIT(q);
    }
  return FROMCHUNK(p);
}
示例#3
0
void *trealloc(void *vp, unsigned newbytes)
{
  void *newp = NULL;

  /* behavior on corner cases conforms to SUSv2 */
  if (vp == NULL)
    return tmalloc(newbytes);

  if (newbytes != 0)
    {
      CHUNK *oldchunk;
      unsigned bytes;

      if ( (newp = tmalloc(newbytes)) == NULL)
        return NULL;
      oldchunk = TOCHUNK(vp);
      bytes = CHUNKSIZE(oldchunk) - sizeof(CHUNK);
      if (bytes > newbytes)
        bytes = newbytes;
      memcpy(newp, vp, bytes);
    }

  tfree(vp);
  return newp;
}