OpenCores
URL https://opencores.org/ocsvn/openrisc_me/openrisc_me/trunk

Subversion Repositories openrisc_me

[/] [openrisc/] [trunk/] [gnu-src/] [gdb-6.8/] [libiberty/] [objalloc.c] - Blame information for rev 157

Details | Compare with Previous | View Log

Line No. Rev Author Line
1 24 jeremybenn
/* objalloc.c -- routines to allocate memory for objects
2
   Copyright 1997 Free Software Foundation, Inc.
3
   Written by Ian Lance Taylor, Cygnus Solutions.
4
 
5
This program is free software; you can redistribute it and/or modify it
6
under the terms of the GNU General Public License as published by the
7
Free Software Foundation; either version 2, or (at your option) any
8
later version.
9
 
10
This program is distributed in the hope that it will be useful,
11
but WITHOUT ANY WARRANTY; without even the implied warranty of
12
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13
GNU General Public License for more details.
14
 
15
You should have received a copy of the GNU General Public License
16
along with this program; if not, write to the Free Software
17
Foundation, 51 Franklin Street - Fifth Floor,
18
Boston, MA 02110-1301, USA.  */
19
 
20
#include "config.h"
21
#include "ansidecl.h"
22
 
23
#include "objalloc.h"
24
 
25
/* Get a definition for NULL.  */
26
#include <stdio.h>
27
 
28
#if VMS
29
#include <stdlib.h>
30
#include <unixlib.h>
31
#else
32
 
33
/* Get a definition for size_t.  */
34
#include <stddef.h>
35
 
36
#ifdef HAVE_STDLIB_H
37
#include <stdlib.h>
38
#else
39
/* For systems with larger pointers than ints, this must be declared.  */
40
extern PTR malloc (size_t);
41
extern void free (PTR);
42
#endif
43
 
44
#endif
45
 
46
/* These routines allocate space for an object.  Freeing allocated
47
   space may or may not free all more recently allocated space.
48
 
49
   We handle large and small allocation requests differently.  If we
50
   don't have enough space in the current block, and the allocation
51
   request is for more than 512 bytes, we simply pass it through to
52
   malloc.  */
53
 
54
/* The objalloc structure is defined in objalloc.h.  */
55
 
56
/* This structure appears at the start of each chunk.  */
57
 
58
struct objalloc_chunk
59
{
60
  /* Next chunk.  */
61
  struct objalloc_chunk *next;
62
  /* If this chunk contains large objects, this is the value of
63
     current_ptr when this chunk was allocated.  If this chunk
64
     contains small objects, this is NULL.  */
65
  char *current_ptr;
66
};
67
 
68
/* The aligned size of objalloc_chunk.  */
69
 
70
#define CHUNK_HEADER_SIZE                                       \
71
  ((sizeof (struct objalloc_chunk) + OBJALLOC_ALIGN - 1)        \
72
   &~ (OBJALLOC_ALIGN - 1))
73
 
74
/* We ask for this much memory each time we create a chunk which is to
75
   hold small objects.  */
76
 
77
#define CHUNK_SIZE (4096 - 32)
78
 
79
/* A request for this amount or more is just passed through to malloc.  */
80
 
81
#define BIG_REQUEST (512)
82
 
83
/* Create an objalloc structure.  */
84
 
85
struct objalloc *
86
objalloc_create (void)
87
{
88
  struct objalloc *ret;
89
  struct objalloc_chunk *chunk;
90
 
91
  ret = (struct objalloc *) malloc (sizeof *ret);
92
  if (ret == NULL)
93
    return NULL;
94
 
95
  ret->chunks = (PTR) malloc (CHUNK_SIZE);
96
  if (ret->chunks == NULL)
97
    {
98
      free (ret);
99
      return NULL;
100
    }
101
 
102
  chunk = (struct objalloc_chunk *) ret->chunks;
103
  chunk->next = NULL;
104
  chunk->current_ptr = NULL;
105
 
106
  ret->current_ptr = (char *) chunk + CHUNK_HEADER_SIZE;
107
  ret->current_space = CHUNK_SIZE - CHUNK_HEADER_SIZE;
108
 
109
  return ret;
110
}
111
 
112
/* Allocate space from an objalloc structure.  */
113
 
114
PTR
115
_objalloc_alloc (struct objalloc *o, unsigned long len)
116
{
117
  /* We avoid confusion from zero sized objects by always allocating
118
     at least 1 byte.  */
119
  if (len == 0)
120
    len = 1;
121
 
122
  len = (len + OBJALLOC_ALIGN - 1) &~ (OBJALLOC_ALIGN - 1);
123
 
124
  if (len <= o->current_space)
125
    {
126
      o->current_ptr += len;
127
      o->current_space -= len;
128
      return (PTR) (o->current_ptr - len);
129
    }
130
 
131
  if (len >= BIG_REQUEST)
132
    {
133
      char *ret;
134
      struct objalloc_chunk *chunk;
135
 
136
      ret = (char *) malloc (CHUNK_HEADER_SIZE + len);
137
      if (ret == NULL)
138
        return NULL;
139
 
140
      chunk = (struct objalloc_chunk *) ret;
141
      chunk->next = (struct objalloc_chunk *) o->chunks;
142
      chunk->current_ptr = o->current_ptr;
143
 
144
      o->chunks = (PTR) chunk;
145
 
146
      return (PTR) (ret + CHUNK_HEADER_SIZE);
147
    }
148
  else
149
    {
150
      struct objalloc_chunk *chunk;
151
 
152
      chunk = (struct objalloc_chunk *) malloc (CHUNK_SIZE);
153
      if (chunk == NULL)
154
        return NULL;
155
      chunk->next = (struct objalloc_chunk *) o->chunks;
156
      chunk->current_ptr = NULL;
157
 
158
      o->current_ptr = (char *) chunk + CHUNK_HEADER_SIZE;
159
      o->current_space = CHUNK_SIZE - CHUNK_HEADER_SIZE;
160
 
161
      o->chunks = (PTR) chunk;
162
 
163
      return objalloc_alloc (o, len);
164
    }
165
}
166
 
167
/* Free an entire objalloc structure.  */
168
 
169
void
170
objalloc_free (struct objalloc *o)
171
{
172
  struct objalloc_chunk *l;
173
 
174
  l = (struct objalloc_chunk *) o->chunks;
175
  while (l != NULL)
176
    {
177
      struct objalloc_chunk *next;
178
 
179
      next = l->next;
180
      free (l);
181
      l = next;
182
    }
183
 
184
  free (o);
185
}
186
 
187
/* Free a block from an objalloc structure.  This also frees all more
188
   recently allocated blocks.  */
189
 
190
void
191
objalloc_free_block (struct objalloc *o, PTR block)
192
{
193
  struct objalloc_chunk *p, *small;
194
  char *b = (char *) block;
195
 
196
  /* First set P to the chunk which contains the block we are freeing,
197
     and set Q to the last small object chunk we see before P.  */
198
  small = NULL;
199
  for (p = (struct objalloc_chunk *) o->chunks; p != NULL; p = p->next)
200
    {
201
      if (p->current_ptr == NULL)
202
        {
203
          if (b > (char *) p && b < (char *) p + CHUNK_SIZE)
204
            break;
205
          small = p;
206
        }
207
      else
208
        {
209
          if (b == (char *) p + CHUNK_HEADER_SIZE)
210
            break;
211
        }
212
    }
213
 
214
  /* If we can't find the chunk, the caller has made a mistake.  */
215
  if (p == NULL)
216
    abort ();
217
 
218
  if (p->current_ptr == NULL)
219
    {
220
      struct objalloc_chunk *q;
221
      struct objalloc_chunk *first;
222
 
223
      /* The block is in a chunk containing small objects.  We can
224
         free every chunk through SMALL, because they have certainly
225
         been allocated more recently.  After SMALL, we will not see
226
         any chunks containing small objects; we can free any big
227
         chunk if the current_ptr is greater than or equal to B.  We
228
         can then reset the new current_ptr to B.  */
229
 
230
      first = NULL;
231
      q = (struct objalloc_chunk *) o->chunks;
232
      while (q != p)
233
        {
234
          struct objalloc_chunk *next;
235
 
236
          next = q->next;
237
          if (small != NULL)
238
            {
239
              if (small == q)
240
                small = NULL;
241
              free (q);
242
            }
243
          else if (q->current_ptr > b)
244
            free (q);
245
          else if (first == NULL)
246
            first = q;
247
 
248
          q = next;
249
        }
250
 
251
      if (first == NULL)
252
        first = p;
253
      o->chunks = (PTR) first;
254
 
255
      /* Now start allocating from this small block again.  */
256
      o->current_ptr = b;
257
      o->current_space = ((char *) p + CHUNK_SIZE) - b;
258
    }
259
  else
260
    {
261
      struct objalloc_chunk *q;
262
      char *current_ptr;
263
 
264
      /* This block is in a large chunk by itself.  We can free
265
         everything on the list up to and including this block.  We
266
         then start allocating from the next chunk containing small
267
         objects, setting current_ptr from the value stored with the
268
         large chunk we are freeing.  */
269
 
270
      current_ptr = p->current_ptr;
271
      p = p->next;
272
 
273
      q = (struct objalloc_chunk *) o->chunks;
274
      while (q != p)
275
        {
276
          struct objalloc_chunk *next;
277
 
278
          next = q->next;
279
          free (q);
280
          q = next;
281
        }
282
 
283
      o->chunks = (PTR) p;
284
 
285
      while (p->current_ptr != NULL)
286
        p = p->next;
287
 
288
      o->current_ptr = current_ptr;
289
      o->current_space = ((char *) p + CHUNK_SIZE) - current_ptr;
290
    }
291
}

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.