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;
29 /* Only keep real realloc and hidden malloc and free to the relevant functions */
31 fprintf(stderr,"free from realloc...");
33 fprintf(stderr,"done\n");
34 return mmalloc(mdp, 0);
35 } else if (ptr == NULL) {
36 return mmalloc(mdp, 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(mdp, size);
51 type = mdp->heapinfo[block].type;
53 THROWF(arg_error,0,"Asked realloc a fragment comming from a *free* block. I'm puzzled.");
57 /* Maybe reallocate a large block to a small fragment. */
59 if (size <= BLOCKSIZE / 2) { // Full block -> Fragment; no need to optimize for time
61 result = mmalloc(mdp, size);
62 if (result != NULL) { // useless (mmalloc never returns NULL), but harmless
63 memcpy(result, ptr, size);
69 /* The new size is a large allocation as well;
70 see if we can hold it in place. */
71 blocks = BLOCKIFY(size);
72 if (blocks < mdp->heapinfo[block].busy_block.size) {
74 /* The new size is smaller; return excess memory to the free list. */
75 //printf("(%s) return excess memory...",xbt_thread_self_name());
76 for (it= block+blocks; it< mdp->heapinfo[block].busy_block.size ; it++)
77 mdp->heapinfo[it].type = 0;
78 mdp->heapinfo[block + blocks].busy_block.size
79 = mdp->heapinfo[block].busy_block.size - blocks;
80 mdp->heapinfo[block].busy_block.size = blocks;
81 mdp->heapinfo[block].busy_block.busy_size = size;
83 mfree(mdp, ADDRESS(block + blocks));
85 } else if (blocks == mdp->heapinfo[block].busy_block.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_block.size;
93 /* Prevent free from actually returning memory to the system. */
94 oldlimit = mdp->heaplimit;
97 mdp->heaplimit = oldlimit;
98 result = mmalloc(mdp, size);
100 mmalloc(mdp, blocks * BLOCKSIZE);
104 memmove(result, ptr, blocks * BLOCKSIZE);
109 /* Old size is a fragment; type is logarithm
110 to base two of the fragment size. */
111 if (size > (size_t) (1 << (type - 1)) && size <= (size_t) (1 << type)) {
112 /* The new size is the same kind of fragment. */
113 //printf("(%s) new size is same kind of fragment...",xbt_thread_self_name());
116 /* The new size is different; allocate a new space,
117 and copy the lesser of the new size and the old. */
118 //printf("(%s) new size is different...",xbt_thread_self_name());
120 result = mmalloc(mdp, size);
124 memcpy(result, ptr, MIN(size, (size_t) 1 << type));
129 //printf("(%s) Done reallocing: %p\n",xbt_thread_self_name(),result);fflush(stdout);