1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/* Free a block of memory allocated by `malloc'.
Copyright 1990, 1991, 1992, 1994 Free Software Foundation, Inc.
Written May 1989 by Mike Haertel.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.
The author may be reached (Email) at the address mike@ai.mit.edu,
or (US mail) as Mike Haertel c/o Free Software Foundation. */
#ifndef _MALLOC_INTERNAL
#define _MALLOC_INTERNAL
#include <malloc.h>
#endif
/* Debugging hook for free. */
void (*__free_hook) __P ((__ptr_t __ptr));
/* List of blocks allocated by memalign. */
struct alignlist *_aligned_blocks = NULL;
/* Return memory to the heap.
Like `free' but don't call a __free_hook if there is one. */
void
_free_internal (ptr)
__ptr_t ptr;
{
int type;
__malloc_size_t block, blocks;
register __malloc_size_t i;
struct list *prev, *next;
block = BLOCK (ptr);
type = _heapinfo[block].busy.type;
switch (type)
{
case 0:
/* Get as many statistics as early as we can. */
--_chunks_used;
_bytes_used -= _heapinfo[block].busy.info.size * BLOCKSIZE;
_bytes_free += _heapinfo[block].busy.info.size * BLOCKSIZE;
/* Find the free cluster previous to this one in the free list.
Start searching at the last block referenced; this may benefit
programs with locality of allocation. */
i = _heapindex;
if (i > block)
while (i > block)
i = _heapinfo[i].free.prev;
else
{
do
i = _heapinfo[i].free.next;
while (i > 0 && i < block);
i = _heapinfo[i].free.prev;
}
/* Determine how to link this block into the free list. */
if (block == i + _heapinfo[i].free.size)
{
/* Coalesce this block with its predecessor. */
_heapinfo[i].free.size += _heapinfo[block].busy.info.size;
block = i;
}
else
{
/* Really link this block back into the free list. */
_heapinfo[block].free.size = _heapinfo[block].busy.info.size;
_heapinfo[block].free.next = _heapinfo[i].free.next;
_heapinfo[block].free.prev = i;
_heapinfo[i].free.next = block;
_heapinfo[_heapinfo[block].free.next].free.prev = block;
++_chunks_free;
}
/* Now that the block is linked in, see if we can coalesce it
with its successor (by deleting its successor from the list
and adding in its size). */
if (block + _heapinfo[block].free.size == _heapinfo[block].free.next)
{
_heapinfo[block].free.size
+= _heapinfo[_heapinfo[block].free.next].free.size;
_heapinfo[block].free.next
= _heapinfo[_heapinfo[block].free.next].free.next;
_heapinfo[_heapinfo[block].free.next].free.prev = block;
--_chunks_free;
}
/* Now see if we can return stuff to the system. */
blocks = _heapinfo[block].free.size;
if (blocks >= FINAL_FREE_BLOCKS && block + blocks == _heaplimit
&& (*__morecore) (0) == ADDRESS (block + blocks))
{
register __malloc_size_t bytes = blocks * BLOCKSIZE;
_heaplimit -= blocks;
(*__morecore) (-bytes);
_heapinfo[_heapinfo[block].free.prev].free.next
= _heapinfo[block].free.next;
_heapinfo[_heapinfo[block].free.next].free.prev
= _heapinfo[block].free.prev;
block = _heapinfo[block].free.prev;
--_chunks_free;
_bytes_free -= bytes;
}
/* Set the next search to begin at this block. */
_heapindex = block;
break;
default:
/* Do some of the statistics. */
--_chunks_used;
_bytes_used -= 1 << type;
++_chunks_free;
_bytes_free += 1 << type;
/* Get the address of the first free fragment in this block. */
prev = (struct list *) ((char *) ADDRESS (block) +
(_heapinfo[block].busy.info.frag.first << type));
if (_heapinfo[block].busy.info.frag.nfree == (BLOCKSIZE >> type) - 1)
{
/* If all fragments of this block are free, remove them
from the fragment list and free the whole block. */
next = prev;
for (i = 1; i < (__malloc_size_t) (BLOCKSIZE >> type); ++i)
next = next->next;
prev->prev->next = next;
if (next != NULL)
next->prev = prev->prev;
_heapinfo[block].busy.type = 0;
_heapinfo[block].busy.info.size = 1;
/* Keep the statistics accurate. */
++_chunks_used;
_bytes_used += BLOCKSIZE;
_chunks_free -= BLOCKSIZE >> type;
_bytes_free -= BLOCKSIZE;
free (ADDRESS (block));
}
else if (_heapinfo[block].busy.info.frag.nfree != 0)
{
/* If some fragments of this block are free, link this
fragment into the fragment list after the first free
fragment of this block. */
/****** Test for no double frees --mann ********/
{
#include <stdio.h>
struct list* tmp = prev;
while (tmp != NULL && BLOCK(tmp) == BLOCK(ptr)) {
if (tmp == ptr) {
fprintf(stderr, "Freeing already freed memory!\n");
abort();
}
tmp = tmp->next;
}
}
/************************************************/
next = (struct list *) ptr;
next->next = prev->next;
next->prev = prev;
prev->next = next;
if (next->next != NULL)
next->next->prev = next;
++_heapinfo[block].busy.info.frag.nfree;
}
else
{
/* No fragments of this block are free, so link this
fragment into the fragment list and announce that
it is the first free fragment of this block. */
prev = (struct list *) ptr;
_heapinfo[block].busy.info.frag.nfree = 1;
_heapinfo[block].busy.info.frag.first = (unsigned long int)
((unsigned long int) ((char *) ptr - (char *) NULL)
% BLOCKSIZE >> type);
prev->next = _fraghead[type].next;
prev->prev = &_fraghead[type];
prev->prev->next = prev;
if (prev->next != NULL)
prev->next->prev = prev;
}
break;
}
}
/* Return memory to the heap. */
void
free (ptr)
__ptr_t ptr;
{
register struct alignlist *l;
if (ptr == NULL)
return;
for (l = _aligned_blocks; l != NULL; l = l->next)
if (l->aligned == ptr)
{
l->aligned = NULL; /* Mark the slot in the list as free. */
ptr = l->exact;
break;
}
if (__free_hook != NULL)
(*__free_hook) (ptr);
else
_free_internal (ptr);
}
|
