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].type;
51 THROWF(arg_error,0,"Asked realloc a fragment comming from a *free* block. I'm puzzled.");
55 /* Maybe reallocate a large block to a small fragment. */
56 if (size <= BLOCKSIZE / 2) {
57 //printf("(%s) alloc large block...",xbt_thread_self_name());
58 result = mmalloc(mdp, size);
60 memcpy(result, ptr, size);
66 /* The new size is a large allocation as well;
67 see if we can hold it in place. */
68 blocks = BLOCKIFY(size);
69 if (blocks < mdp->heapinfo[block].busy_block.size) {
70 /* The new size is smaller; return excess memory to the free list. */
71 //printf("(%s) return excess memory...",xbt_thread_self_name());
72 mdp->heapinfo[block + blocks].type = 0;
73 mdp->heapinfo[block + blocks].busy_block.size
74 = mdp->heapinfo[block].busy_block.size - blocks;
75 mdp->heapinfo[block].busy_block.size = blocks;
76 mdp->heapinfo[block].busy_block.busy_size = size;
77 mfree(mdp, ADDRESS(block + blocks));
79 } else if (blocks == mdp->heapinfo[block].busy_block.size) {
80 /* No size change necessary. */
83 /* Won't fit, so allocate a new region that will.
84 Free the old region first in case there is sufficient
85 adjacent free space to grow without moving. */
86 blocks = mdp->heapinfo[block].busy_block.size;
87 /* Prevent free from actually returning memory to the system. */
88 oldlimit = mdp->heaplimit;
91 mdp->heaplimit = oldlimit;
92 result = mmalloc(mdp, size);
94 mmalloc(mdp, blocks * BLOCKSIZE);
98 memmove(result, ptr, blocks * BLOCKSIZE);
103 /* Old size is a fragment; type is logarithm
104 to base two of the fragment size. */
105 if (size > (size_t) (1 << (type - 1)) && size <= (size_t) (1 << type)) {
106 /* The new size is the same kind of fragment. */
107 //printf("(%s) new size is same kind of fragment...",xbt_thread_self_name());
110 /* The new size is different; allocate a new space,
111 and copy the lesser of the new size and the old. */
112 //printf("(%s) new size is different...",xbt_thread_self_name());
114 result = mmalloc(mdp, size);
118 memcpy(result, ptr, MIN(size, (size_t) 1 << type));
123 //printf("(%s) Done reallocing: %p\n",xbt_thread_self_name(),result);fflush(stdout);