/* [allocate_block] is called by [caml_fl_allocate]. Given a suitable free
block and the desired size, it allocates a new block from the free
block. There are three cases:
0. The free block has the desired size. Detach the block from the
free-list and return it.
1. The free block is 1 word longer than the desired size. Detach
the block from the free list. The remaining word cannot be linked:
turn it into an empty block (header only), and return the rest.
2. The free block is big enough. Split it in two and return the right
block.
In all cases, the allocated block is right-justified in the free block:
it is located in the high-address words of the free block. This way,
the linking of the free-list does not change in case 2.
*/
static char *allocate_block (mlsize_t wh_sz, int flpi, char *prev, char *cur)
{
header_t h = Hd_bp (cur);
Assert (Whsize_hd (h) >= wh_sz);
if (Wosize_hd (h) < wh_sz + 1){ /* Cases 0 and 1. */
caml_fl_cur_size -= Whsize_hd (h);
Next (prev) = Next (cur);
Assert (Is_in_heap (Next (prev)) || Next (prev) == NULL);
if (caml_fl_merge == cur) caml_fl_merge = prev;
#ifdef DEBUG
fl_last = NULL;
#endif
/* In case 1, the following creates the empty block correctly.
In case 0, it gives an invalid header to the block. The function
calling [caml_fl_allocate] will overwrite it. */
Hd_op (cur) = Make_header (0, 0, Caml_white);
if (policy == Policy_first_fit){
if (flpi + 1 < flp_size && flp[flpi + 1] == cur){
flp[flpi + 1] = prev;
}else if (flpi == flp_size - 1){
beyond = (prev == Fl_head) ? NULL : prev;
-- flp_size;
}
}
}else{ /* Case 2. */
caml_fl_cur_size -= wh_sz;
Hd_op (cur) = Make_header (Wosize_hd (h) - wh_sz, 0, Caml_blue);
}
if (policy == Policy_next_fit) fl_prev = prev;
return cur + Bosize_hd (h) - Bsize_wsize (wh_sz);
}
/* [allocate_block] is called by [caml_fl_allocate]. Given a suitable free
block and the desired size, it allocates a new block from the free
block. There are three cases:
0. The free block has the desired size. Detach the block from the
free-list and return it.
1. The free block is 1 word longer than the desired size. Detach
the block from the free list. The remaining word cannot be linked:
turn it into an empty block (header only), and return the rest.
2. The free block is big enough. Split it in two and return the right
block.
In all cases, the allocated block is right-justified in the free block:
it is located in the high-address words of the free block. This way,
the linking of the free-list does not change in case 2.
*/
static char *allocate_block (mlsize_t wh_sz, char *prev, char *cur)
{
header_t h = Hd_bp (cur);
Assert (Whsize_hd (h) >= wh_sz);
if (Wosize_hd (h) < wh_sz + 1){ /* Cases 0 and 1. */
caml_fl_cur_size -= Whsize_hd (h);
Next (prev) = Next (cur);
Assert (Is_in_heap (Next (prev)) || Next (prev) == NULL);
if (caml_fl_merge == cur) caml_fl_merge = prev;
#ifdef DEBUG
fl_last = NULL;
#endif
/* In case 1, the following creates the empty block correctly.
In case 0, it gives an invalid header to the block. The function
calling [caml_fl_allocate] will overwrite it. */
Hd_op (cur) = Make_header (0, 0, Caml_white);
}else{ /* Case 2. */
caml_fl_cur_size -= wh_sz;
Hd_op (cur) = Make_header (Wosize_hd (h) - wh_sz, 0, Caml_blue);
}
fl_prev = prev;
return cur + Bosize_hd (h) - Bsize_wsize (wh_sz);
}