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;
31 return (mmalloc(md, 0));
32 } else if (ptr == NULL) {
33 return (mmalloc(md, size));
38 //printf("(%s)realloc %p to %d...",xbt_thread_self_name(),ptr,(int)size);
40 if ((char *) ptr < (char *) mdp->heapbase || BLOCK(ptr) > mdp->heapsize) {
42 ("FIXME. Ouch, this pointer is not mine. I will malloc it instead of reallocing it. (please report this bug)\n");
43 result = mmalloc(md, size);
48 if (mdp->mrealloc_hook != NULL) {
49 return mdp->mrealloc_hook(md, ptr, size);
54 type = mdp->heapinfo[block].busy.type;
57 /* Maybe reallocate a large block to a small fragment. */
58 if (size <= BLOCKSIZE / 2) {
59 //printf("(%s) alloc large block...",xbt_thread_self_name());
60 result = mmalloc(md, size);
62 memcpy(result, ptr, size);
68 /* The new size is a large allocation as well;
69 see if we can hold it in place. */
70 blocks = BLOCKIFY(size);
71 if (blocks < mdp->heapinfo[block].busy.info.size) {
72 /* The new size is smaller; return excess memory to the free list. */
73 //printf("(%s) return excess memory...",xbt_thread_self_name());
74 mdp->heapinfo[block + blocks].busy.type = 0;
75 mdp->heapinfo[block + blocks].busy.info.size
76 = mdp->heapinfo[block].busy.info.size - blocks;
77 mdp->heapinfo[block].busy.info.size = blocks;
78 mfree(md, ADDRESS(block + blocks));
80 } else if (blocks == mdp->heapinfo[block].busy.info.size) {
81 /* No size change necessary. */
84 /* Won't fit, so allocate a new region that will.
85 Free the old region first in case there is sufficient
86 adjacent free space to grow without moving. */
87 blocks = mdp->heapinfo[block].busy.info.size;
88 /* Prevent free from actually returning memory to the system. */
89 oldlimit = mdp->heaplimit;
92 mdp->heaplimit = oldlimit;
93 result = mmalloc(md, size);
95 mmalloc(md, blocks * BLOCKSIZE);
99 memmove(result, ptr, blocks * BLOCKSIZE);
104 /* Old size is a fragment; type is logarithm
105 to base two of the fragment size. */
106 if (size > (size_t) (1 << (type - 1)) && size <= (size_t) (1 << type)) {
107 /* The new size is the same kind of fragment. */
108 //printf("(%s) new size is same kind of fragment...",xbt_thread_self_name());
111 /* The new size is different; allocate a new space,
112 and copy the lesser of the new size and the old. */
113 //printf("(%s) new size is different...",xbt_thread_self_name());
115 result = mmalloc(md, size);
119 memcpy(result, ptr, MIN(size, (size_t) 1 << type));
124 //printf("(%s) Done reallocing: %p\n",xbt_thread_self_name(),result);fflush(stdout);