- block = BLOCK (ptr);
-
- type = mdp -> heapinfo[block].busy.type;
- switch (type)
- {
- case 0:
- /* Maybe reallocate a large block to a small fragment. */
- if (size <= BLOCKSIZE / 2)
- {
- result = mmalloc (md, size);
- if (result != NULL)
- {
- memcpy (result, ptr, size);
- mfree (md, ptr);
- return (result);
- }
- }
-
- /* The new size is a large allocation as well;
- see if we can hold it in place. */
- blocks = BLOCKIFY (size);
- if (blocks < mdp -> heapinfo[block].busy.info.size)
- {
- /* The new size is smaller; return excess memory to the free list. */
- mdp -> heapinfo[block + blocks].busy.type = 0;
- mdp -> heapinfo[block + blocks].busy.info.size
- = mdp -> heapinfo[block].busy.info.size - blocks;
- mdp -> heapinfo[block].busy.info.size = blocks;
- mfree (md, ADDRESS (block + blocks));
- result = ptr;
- }
- else if (blocks == mdp -> heapinfo[block].busy.info.size)
- {
- /* No size change necessary. */
- result = ptr;
- }
- else
- {
- /* Won't fit, so allocate a new region that will.
- Free the old region first in case there is sufficient
- adjacent free space to grow without moving. */
- blocks = mdp -> heapinfo[block].busy.info.size;
- /* Prevent free from actually returning memory to the system. */
- oldlimit = mdp -> heaplimit;
- mdp -> heaplimit = 0;
- mfree (md, ptr);
- mdp -> heaplimit = oldlimit;
- result = mmalloc (md, size);
- if (result == NULL)
- {
- mmalloc (md, blocks * BLOCKSIZE);
- return (NULL);
- }
- if (ptr != result)
- {
- memmove (result, ptr, blocks * BLOCKSIZE);
- }
- }
- break;
-
- default:
- /* Old size is a fragment; type is logarithm
- to base two of the fragment size. */
- if (size > (size_t) (1 << (type - 1)) && size <= (size_t) (1 << type))
- {
- /* The new size is the same kind of fragment. */
- result = ptr;
- }
- else
- {
- /* The new size is different; allocate a new space,
- and copy the lesser of the new size and the old. */
- result = mmalloc (md, size);
- if (result == NULL)
- {
- return (NULL);
- }
- memcpy (result, ptr, MIN (size, (size_t) 1 << type));
- mfree (md, ptr);
- }
- break;
- }