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);
}
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);
}
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;
}