1 /* Change the size of a block allocated by `mmalloc'.
2 Copyright 1990, 1991 Free Software Foundation
3 Written May 1989 by Mike Haertel. */
5 /* Copyright (c) 2010. The SimGrid Team.
6 * All rights reserved. */
8 /* This program is free software; you can redistribute it and/or modify it
9 * under the terms of the license (GNU LGPL) which comes with this package. */
11 #include <string.h> /* Prototypes for memcpy, memmove, memset, etc */
12 #include <stdlib.h> /* abort */
14 #include "mmprivate.h"
16 /* Resize the given region to the new size, returning a pointer
17 to the (possibly moved) region. This is optimized for speed;
18 some benchmarks seem to indicate that greater compactness is
19 achieved by unconditionally allocating and copying to a
20 new region. This module has incestuous knowledge of the
21 internals of both mfree and mmalloc. */
23 void *mrealloc(xbt_mheap_t mdp, void *ptr, size_t size)
27 size_t block, blocks, oldlimit;
31 return (mmalloc(mdp, 0));
32 } else if (ptr == NULL) {
33 return (mmalloc(mdp, size));
37 //printf("(%s)realloc %p to %d...",xbt_thread_self_name(),ptr,(int)size);
39 if ((char *) ptr < (char *) mdp->heapbase || BLOCK(ptr) > mdp->heapsize) {
41 ("FIXME. Ouch, this pointer is not mine, refusing to proceed (another solution would be to malloc it instead of reallocing it, see source code)\n");
42 result = mmalloc(mdp, size);
49 type = mdp->heapinfo[block].busy.type;
52 /* Maybe reallocate a large block to a small fragment. */
53 if (size <= BLOCKSIZE / 2) {
54 //printf("(%s) alloc large block...",xbt_thread_self_name());
55 result = mmalloc(mdp, size);
57 memcpy(result, ptr, size);
63 /* The new size is a large allocation as well;
64 see if we can hold it in place. */
65 blocks = BLOCKIFY(size);
66 if (blocks < mdp->heapinfo[block].busy.info.block.size) {
67 /* The new size is smaller; return excess memory to the free list. */
68 //printf("(%s) return excess memory...",xbt_thread_self_name());
69 mdp->heapinfo[block + blocks].busy.type = 0;
70 mdp->heapinfo[block + blocks].busy.info.block.size
71 = mdp->heapinfo[block].busy.info.block.size - blocks;
72 mdp->heapinfo[block].busy.info.block.size = blocks;
73 mdp->heapinfo[block].busy.info.block.busy_size = size;
74 mfree(mdp, ADDRESS(block + blocks));
76 } else if (blocks == mdp->heapinfo[block].busy.info.block.size) {
77 /* No size change necessary. */
80 /* Won't fit, so allocate a new region that will.
81 Free the old region first in case there is sufficient
82 adjacent free space to grow without moving. */
83 blocks = mdp->heapinfo[block].busy.info.block.size;
84 /* Prevent free from actually returning memory to the system. */
85 oldlimit = mdp->heaplimit;
88 mdp->heaplimit = oldlimit;
89 result = mmalloc(mdp, size);
91 mmalloc(mdp, blocks * BLOCKSIZE);
95 memmove(result, ptr, blocks * BLOCKSIZE);
100 /* Old size is a fragment; type is logarithm
101 to base two of the fragment size. */
102 if (size > (size_t) (1 << (type - 1)) && size <= (size_t) (1 << type)) {
103 /* The new size is the same kind of fragment. */
104 //printf("(%s) new size is same kind of fragment...",xbt_thread_self_name());
107 /* The new size is different; allocate a new space,
108 and copy the lesser of the new size and the old. */
109 //printf("(%s) new size is different...",xbt_thread_self_name());
111 result = mmalloc(mdp, size);
115 memcpy(result, ptr, MIN(size, (size_t) 1 << type));
120 //printf("(%s) Done reallocing: %p\n",xbt_thread_self_name(),result);fflush(stdout);