summaryrefslogtreecommitdiff
path: root/lib/xalloc.h
blob: 6c9b53bf6fabbdc3c96f0e44a24b0bb778574250 (plain)
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
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
/* xalloc.h -- malloc with out-of-memory checking

   Copyright (C) 1990-2000, 2003-2004, 2006-2013 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#ifndef XALLOC_H_
#define XALLOC_H_

#include <stddef.h>

#include "xalloc-oversized.h"

#ifndef _GL_INLINE_HEADER_BEGIN
 #error "Please include config.h first."
#endif
_GL_INLINE_HEADER_BEGIN
#ifndef XALLOC_INLINE
# define XALLOC_INLINE _GL_INLINE
#endif

#ifdef __cplusplus
extern "C" {
#endif


#if __GNUC__ >= 3
# define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
#else
# define _GL_ATTRIBUTE_MALLOC
#endif

#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
# define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
#else
# define _GL_ATTRIBUTE_ALLOC_SIZE(args)
#endif

/* This function is always triggered when memory is exhausted.
   It must be defined by the application, either explicitly
   or by using gnulib's xalloc-die module.  This is the
   function to call when one wants the program to die because of a
   memory allocation failure.  */
extern _Noreturn void xalloc_die (void);

void *xmalloc (size_t s)
      _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
void *xzalloc (size_t s)
      _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
void *xcalloc (size_t n, size_t s)
      _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
void *xrealloc (void *p, size_t s)
      _GL_ATTRIBUTE_ALLOC_SIZE ((2));
void *x2realloc (void *p, size_t *pn);
void *xmemdup (void const *p, size_t s)
      _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2));
char *xstrdup (char const *str)
      _GL_ATTRIBUTE_MALLOC;

/* In the following macros, T must be an elementary or structure/union or
   typedef'ed type, or a pointer to such a type.  To apply one of the
   following macros to a function pointer or array type, you need to typedef
   it first and use the typedef name.  */

/* Allocate an object of type T dynamically, with error checking.  */
/* extern t *XMALLOC (typename t); */
#define XMALLOC(t) ((t *) xmalloc (sizeof (t)))

/* Allocate memory for N elements of type T, with error checking.  */
/* extern t *XNMALLOC (size_t n, typename t); */
#define XNMALLOC(n, t) \
   ((t *) (sizeof (t) == 1 ? xmalloc (n) : xnmalloc (n, sizeof (t))))

/* Allocate an object of type T dynamically, with error checking,
   and zero it.  */
/* extern t *XZALLOC (typename t); */
#define XZALLOC(t) ((t *) xzalloc (sizeof (t)))

/* Allocate memory for N elements of type T, with error checking,
   and zero it.  */
/* extern t *XCALLOC (size_t n, typename t); */
#define XCALLOC(n, t) \
   ((t *) (sizeof (t) == 1 ? xzalloc (n) : xcalloc (n, sizeof (t))))


/* Allocate an array of N objects, each with S bytes of memory,
   dynamically, with error checking.  S must be nonzero.  */

XALLOC_INLINE void *xnmalloc (size_t n, size_t s)
                    _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2));
XALLOC_INLINE void *
xnmalloc (size_t n, size_t s)
{
  if (xalloc_oversized (n, s))
    xalloc_die ();
  return xmalloc (n * s);
}

/* Change the size of an allocated block of memory P to an array of N
   objects each of S bytes, with error checking.  S must be nonzero.  */

XALLOC_INLINE void *xnrealloc (void *p, size_t n, size_t s)
                    _GL_ATTRIBUTE_ALLOC_SIZE ((2, 3));
XALLOC_INLINE void *
xnrealloc (void *p, size_t n, size_t s)
{
  if (xalloc_oversized (n, s))
    xalloc_die ();
  return xrealloc (p, n * s);
}

/* If P is null, allocate a block of at least *PN such objects;
   otherwise, reallocate P so that it contains more than *PN objects
   each of S bytes.  *PN must be nonzero unless P is null, and S must
   be nonzero.  Set *PN to the new number of objects, and return the
   pointer to the new block.  *PN is never set to zero, and the
   returned pointer is never null.

   Repeated reallocations are guaranteed to make progress, either by
   allocating an initial block with a nonzero size, or by allocating a
   larger block.

   In the following implementation, nonzero sizes are increased by a
   factor of approximately 1.5 so that repeated reallocations have
   O(N) overall cost rather than O(N**2) cost, but the
   specification for this function does not guarantee that rate.

   Here is an example of use:

     int *p = NULL;
     size_t used = 0;
     size_t allocated = 0;

     void
     append_int (int value)
       {
         if (used == allocated)
           p = x2nrealloc (p, &allocated, sizeof *p);
         p[used++] = value;
       }

   This causes x2nrealloc to allocate a block of some nonzero size the
   first time it is called.

   To have finer-grained control over the initial size, set *PN to a
   nonzero value before calling this function with P == NULL.  For
   example:

     int *p = NULL;
     size_t used = 0;
     size_t allocated = 0;
     size_t allocated1 = 1000;

     void
     append_int (int value)
       {
         if (used == allocated)
           {
             p = x2nrealloc (p, &allocated1, sizeof *p);
             allocated = allocated1;
           }
         p[used++] = value;
       }

   */

XALLOC_INLINE void *
x2nrealloc (void *p, size_t *pn, size_t s)
{
  size_t n = *pn;

  if (! p)
    {
      if (! n)
        {
          /* The approximate size to use for initial small allocation
             requests, when the invoking code specifies an old size of
             zero.  This is the largest "small" request for the GNU C
             library malloc.  */
          enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };

          n = DEFAULT_MXFAST / s;
          n += !n;
        }
    }
  else
    {
      /* Set N = ceil (1.5 * N) so that progress is made if N == 1.
         Check for overflow, so that N * S stays in size_t range.
         The check is slightly conservative, but an exact check isn't
         worth the trouble.  */
      if ((size_t) -1 / 3 * 2 / s <= n)
        xalloc_die ();
      n += (n + 1) / 2;
    }

  *pn = n;
  return xrealloc (p, n * s);
}

/* Return a pointer to a new buffer of N bytes.  This is like xmalloc,
   except it returns char *.  */

XALLOC_INLINE char *xcharalloc (size_t n)
                    _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1));
XALLOC_INLINE char *
xcharalloc (size_t n)
{
  return XNMALLOC (n, char);
}

#ifdef __cplusplus
}

/* C++ does not allow conversions from void * to other pointer types
   without a cast.  Use templates to work around the problem when
   possible.  */

template <typename T> inline T *
xrealloc (T *p, size_t s)
{
  return (T *) xrealloc ((void *) p, s);
}

template <typename T> inline T *
xnrealloc (T *p, size_t n, size_t s)
{
  return (T *) xnrealloc ((void *) p, n, s);
}

template <typename T> inline T *
x2realloc (T *p, size_t *pn)
{
  return (T *) x2realloc ((void *) p, pn);
}

template <typename T> inline T *
x2nrealloc (T *p, size_t *pn, size_t s)
{
  return (T *) x2nrealloc ((void *) p, pn, s);
}

template <typename T> inline T *
xmemdup (T const *p, size_t s)
{
  return (T *) xmemdup ((void const *) p, s);
}

#endif


#endif /* !XALLOC_H_ */