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 */
13 #include "mmprivate.h"
15 /* Resize the given region to the new size, returning a pointer
16 to the (possibly moved) region. This is optimized for speed;
17 some benchmarks seem to indicate that greater compactness is
18 achieved by unconditionally allocating and copying to a
19 new region. This module has incestuous knowledge of the
20 internals of both mfree and mmalloc. */
22 void *mrealloc(void *md, void *ptr, size_t size)
27 size_t block, blocks, oldlimit;
32 return (mmalloc(md, 0));
33 } else if (ptr == NULL) {
34 return (mmalloc(md, size));
39 //printf("(%s)realloc %p to %d...",xbt_thread_self_name(),ptr,(int)size);
41 if ((char *) ptr < (char *) mdp->heapbase || BLOCK(ptr) > mdp->heapsize) {
43 ("FIXME. Ouch, this pointer is not mine. I will malloc it instead of reallocing it. (please report this bug)\n");
44 result = mmalloc(md, size);
50 if (mdp->mrealloc_hook != NULL) {
52 return ((*mdp->mrealloc_hook) (md, ptr, size));
57 type = mdp->heapinfo[block].busy.type;
60 /* Maybe reallocate a large block to a small fragment. */
61 if (size <= BLOCKSIZE / 2) {
63 //printf("(%s) alloc large block...",xbt_thread_self_name());
64 result = mmalloc(md, size);
66 memcpy(result, ptr, size);
72 /* The new size is a large allocation as well;
73 see if we can hold it in place. */
75 blocks = BLOCKIFY(size);
76 if (blocks < mdp->heapinfo[block].busy.info.size) {
77 /* The new size is smaller; return excess memory to the free list. */
78 //printf("(%s) return excess memory...",xbt_thread_self_name());
79 mdp->heapinfo[block + blocks].busy.type = 0;
80 mdp->heapinfo[block + blocks].busy.info.size
81 = mdp->heapinfo[block].busy.info.size - blocks;
82 mdp->heapinfo[block].busy.info.size = blocks;
83 mfree(md, ADDRESS(block + blocks));
85 } else if (blocks == mdp->heapinfo[block].busy.info.size) {
86 /* No size change necessary. */
89 /* Won't fit, so allocate a new region that will.
90 Free the old region first in case there is sufficient
91 adjacent free space to grow without moving. */
92 blocks = mdp->heapinfo[block].busy.info.size;
93 /* Prevent free from actually returning memory to the system. */
94 oldlimit = mdp->heaplimit;
97 mdp->heaplimit = oldlimit;
99 result = mmalloc(md, size);
100 if (result == NULL) {
101 mmalloc(md, blocks * BLOCKSIZE);
105 memmove(result, ptr, blocks * BLOCKSIZE);
111 /* Old size is a fragment; type is logarithm
112 to base two of the fragment size. */
113 if (size > (size_t) (1 << (type - 1)) && size <= (size_t) (1 << type)) {
114 /* The new size is the same kind of fragment. */
115 //printf("(%s) new size is same kind of fragment...",xbt_thread_self_name());
118 /* The new size is different; allocate a new space,
119 and copy the lesser of the new size and the old. */
120 //printf("(%s) new size is different...",xbt_thread_self_name());
123 result = mmalloc(md, size);
127 memcpy(result, ptr, MIN(size, (size_t) 1 << type));
132 //printf("(%s) Done reallocing: %p\n",xbt_thread_self_name(),result);fflush(stdout);