1 /* xmalloc.c -- malloc with out of memory checking
2
3 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
4 1999, 2000, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software Foundation,
18 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
19
20 #ifdef HAVE_CONFIG_H
21 # include <config.h>
22 #endif
23
24 #include "xalloc.h"
25
26 #include <stdlib.h>
27 #include <string.h>
28
29 #ifndef SIZE_MAX
30 # define SIZE_MAX ((size_t) -1)
31 #endif
32
33 /* 1 if calloc is known to be compatible with GNU calloc. This
34 matters if we are not also using the calloc module, which defines
35 HAVE_CALLOC and supports the GNU API even on non-GNU platforms. */
36 #if defined HAVE_CALLOC || defined __GLIBC__
37 enum { HAVE_GNU_CALLOC = 1 };
38 #else
39 enum { HAVE_GNU_CALLOC = 0 };
40 #endif
41
42 /* Allocate an array of N objects, each with S bytes of memory,
43 dynamically, with error checking. S must be nonzero. */
44
45 static inline void *
xnmalloc_inline(size_t n,size_t s)46 xnmalloc_inline (size_t n, size_t s)
47 {
48 void *p;
49 if (xalloc_oversized (n, s) || (! (p = malloc (n * s)) && n != 0))
50 xalloc_die ();
51 return p;
52 }
53
54 void *
xnmalloc(size_t n,size_t s)55 xnmalloc (size_t n, size_t s)
56 {
57 return xnmalloc_inline (n, s);
58 }
59
60 /* Allocate N bytes of memory dynamically, with error checking. */
61
62 void *
xmalloc(size_t n)63 xmalloc (size_t n)
64 {
65 return xnmalloc_inline (n, 1);
66 }
67
68 /* Change the size of an allocated block of memory P to an array of N
69 objects each of S bytes, with error checking. S must be nonzero. */
70
71 static inline void *
xnrealloc_inline(void * p,size_t n,size_t s)72 xnrealloc_inline (void *p, size_t n, size_t s)
73 {
74 if (xalloc_oversized (n, s) || (! (p = realloc (p, n * s)) && n != 0))
75 xalloc_die ();
76 return p;
77 }
78
79 void *
xnrealloc(void * p,size_t n,size_t s)80 xnrealloc (void *p, size_t n, size_t s)
81 {
82 return xnrealloc_inline (p, n, s);
83 }
84
85 /* Change the size of an allocated block of memory P to N bytes,
86 with error checking. */
87
88 void *
xrealloc(void * p,size_t n)89 xrealloc (void *p, size_t n)
90 {
91 return xnrealloc_inline (p, n, 1);
92 }
93
94
95 /* If P is null, allocate a block of at least *PN such objects;
96 otherwise, reallocate P so that it contains more than *PN objects
97 each of S bytes. *PN must be nonzero unless P is null, and S must
98 be nonzero. Set *PN to the new number of objects, and return the
99 pointer to the new block. *PN is never set to zero, and the
100 returned pointer is never null.
101
102 Repeated reallocations are guaranteed to make progress, either by
103 allocating an initial block with a nonzero size, or by allocating a
104 larger block.
105
106 In the following implementation, nonzero sizes are doubled so that
107 repeated reallocations have O(N log N) overall cost rather than
108 O(N**2) cost, but the specification for this function does not
109 guarantee that sizes are doubled.
110
111 Here is an example of use:
112
113 int *p = NULL;
114 size_t used = 0;
115 size_t allocated = 0;
116
117 void
118 append_int (int value)
119 {
120 if (used == allocated)
121 p = x2nrealloc (p, &allocated, sizeof *p);
122 p[used++] = value;
123 }
124
125 This causes x2nrealloc to allocate a block of some nonzero size the
126 first time it is called.
127
128 To have finer-grained control over the initial size, set *PN to a
129 nonzero value before calling this function with P == NULL. For
130 example:
131
132 int *p = NULL;
133 size_t used = 0;
134 size_t allocated = 0;
135 size_t allocated1 = 1000;
136
137 void
138 append_int (int value)
139 {
140 if (used == allocated)
141 {
142 p = x2nrealloc (p, &allocated1, sizeof *p);
143 allocated = allocated1;
144 }
145 p[used++] = value;
146 }
147
148 */
149
150 static inline void *
x2nrealloc_inline(void * p,size_t * pn,size_t s)151 x2nrealloc_inline (void *p, size_t *pn, size_t s)
152 {
153 size_t n = *pn;
154
155 if (! p)
156 {
157 if (! n)
158 {
159 /* The approximate size to use for initial small allocation
160 requests, when the invoking code specifies an old size of
161 zero. 64 bytes is the largest "small" request for the
162 GNU C library malloc. */
163 enum { DEFAULT_MXFAST = 64 };
164
165 n = DEFAULT_MXFAST / s;
166 n += !n;
167 }
168 }
169 else
170 {
171 if (SIZE_MAX / 2 / s < n)
172 xalloc_die ();
173 n *= 2;
174 }
175
176 *pn = n;
177 return xrealloc (p, n * s);
178 }
179
180 void *
x2nrealloc(void * p,size_t * pn,size_t s)181 x2nrealloc (void *p, size_t *pn, size_t s)
182 {
183 return x2nrealloc_inline (p, pn, s);
184 }
185
186 /* If P is null, allocate a block of at least *PN bytes; otherwise,
187 reallocate P so that it contains more than *PN bytes. *PN must be
188 nonzero unless P is null. Set *PN to the new block's size, and
189 return the pointer to the new block. *PN is never set to zero, and
190 the returned pointer is never null. */
191
192 void *
x2realloc(void * p,size_t * pn)193 x2realloc (void *p, size_t *pn)
194 {
195 return x2nrealloc_inline (p, pn, 1);
196 }
197
198 /* Allocate S bytes of zeroed memory dynamically, with error checking.
199 There's no need for xnzalloc (N, S), since it would be equivalent
200 to xcalloc (N, S). */
201
202 void *
xzalloc(size_t s)203 xzalloc (size_t s)
204 {
205 return memset (xmalloc (s), 0, s);
206 }
207
208 /* Allocate zeroed memory for N elements of S bytes, with error
209 checking. S must be nonzero. */
210
211 void *
xcalloc(size_t n,size_t s)212 xcalloc (size_t n, size_t s)
213 {
214 void *p;
215 /* Test for overflow, since some calloc implementations don't have
216 proper overflow checks. But omit overflow and size-zero tests if
217 HAVE_GNU_CALLOC, since GNU calloc catches overflow and never
218 returns NULL if successful. */
219 if ((! HAVE_GNU_CALLOC && xalloc_oversized (n, s))
220 || (! (p = calloc (n, s)) && (HAVE_GNU_CALLOC || n != 0)))
221 xalloc_die ();
222 return p;
223 }
224
225 /* Clone an object P of size S, with error checking. There's no need
226 for xnmemdup (P, N, S), since xmemdup (P, N * S) works without any
227 need for an arithmetic overflow check. */
228
229 void *
xmemdup(void const * p,size_t s)230 xmemdup (void const *p, size_t s)
231 {
232 return memcpy (xmalloc (s), p, s);
233 }
234
235 /* Clone STRING. */
236
237 char *
xstrdup(char const * string)238 xstrdup (char const *string)
239 {
240 return xmemdup (string, strlen (string) + 1);
241 }
242