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(void *md, void *ptr, size_t size)
28 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, refusing to proceed (another solution would be to malloc it instead of reallocing it, see source code)\n");
44 result = mmalloc(md, size);
51 type = mdp->heapinfo[block].busy.type;
54 /* Maybe reallocate a large block to a small fragment. */
55 if (size <= BLOCKSIZE / 2) {
56 //printf("(%s) alloc large block...",xbt_thread_self_name());
57 result = mmalloc(md, size);
59 memcpy(result, ptr, size);
65 /* The new size is a large allocation as well;
66 see if we can hold it in place. */
67 blocks = BLOCKIFY(size);
68 if (blocks < mdp->heapinfo[block].busy.info.block.size) {
69 /* The new size is smaller; return excess memory to the free list. */
70 //printf("(%s) return excess memory...",xbt_thread_self_name());
71 mdp->heapinfo[block + blocks].busy.type = 0;
72 mdp->heapinfo[block + blocks].busy.info.block.size
73 = mdp->heapinfo[block].busy.info.block.size - blocks;
74 mdp->heapinfo[block].busy.info.block.size = blocks;
75 mdp->heapinfo[block].busy.info.block.busy_size = size;
76 mfree(md, ADDRESS(block + blocks));
78 } else if (blocks == mdp->heapinfo[block].busy.info.block.size) {
79 /* No size change necessary. */
82 /* Won't fit, so allocate a new region that will.
83 Free the old region first in case there is sufficient
84 adjacent free space to grow without moving. */
85 blocks = mdp->heapinfo[block].busy.info.block.size;
86 /* Prevent free from actually returning memory to the system. */
87 oldlimit = mdp->heaplimit;
90 mdp->heaplimit = oldlimit;
91 result = mmalloc(md, size);
93 mmalloc(md, blocks * BLOCKSIZE);
97 memmove(result, ptr, blocks * BLOCKSIZE);
102 /* Old size is a fragment; type is logarithm
103 to base two of the fragment size. */
104 if (size > (size_t) (1 << (type - 1)) && size <= (size_t) (1 << type)) {
105 /* The new size is the same kind of fragment. */
106 //printf("(%s) new size is same kind of fragment...",xbt_thread_self_name());
109 /* The new size is different; allocate a new space,
110 and copy the lesser of the new size and the old. */
111 //printf("(%s) new size is different...",xbt_thread_self_name());
113 result = mmalloc(md, size);
117 memcpy(result, ptr, MIN(size, (size_t) 1 << type));
122 //printf("(%s) Done reallocing: %p\n",xbt_thread_self_name(),result);fflush(stdout);