1 /* xalloc.h -- malloc with out-of-memory checking 2 3 Copyright (C) 1990-2000, 2003-2004, 2006-2011 Free Software Foundation, Inc. 4 5 This program is free software: you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any 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, see <http://www.gnu.org/licenses/>. */ 17 18 #ifndef XALLOC_H_ 19 # define XALLOC_H_ 20 21 # include <stddef.h> 22 23 # include "xalloc-oversized.h" 24 25 # ifdef __cplusplus 26 extern "C" { 27 # endif 28 29 30 # if __GNUC__ >= 3 31 # define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__)) 32 # else 33 # define _GL_ATTRIBUTE_MALLOC 34 # endif 35 36 # if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) 37 # define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args)) 38 # else 39 # define _GL_ATTRIBUTE_ALLOC_SIZE(args) 40 # endif 41 42 /* This function is always triggered when memory is exhausted. 43 It must be defined by the application, either explicitly 44 or by using gnulib's xalloc-die module. This is the 45 function to call when one wants the program to die because of a 46 memory allocation failure. */ 47 extern _Noreturn void xalloc_die (void); 48 49 void *xmalloc (size_t s) 50 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1)); 51 void *xzalloc (size_t s) 52 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1)); 53 void *xcalloc (size_t n, size_t s) 54 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2)); 55 void *xrealloc (void *p, size_t s) 56 _GL_ATTRIBUTE_ALLOC_SIZE ((2)); 57 void *x2realloc (void *p, size_t *pn); 58 void *xmemdup (void const *p, size_t s) 59 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2)); 60 char *xstrdup (char const *str) 61 _GL_ATTRIBUTE_MALLOC; 62 63 /* In the following macros, T must be an elementary or structure/union or 64 typedef'ed type, or a pointer to such a type. To apply one of the 65 following macros to a function pointer or array type, you need to typedef 66 it first and use the typedef name. */ 67 68 /* Allocate an object of type T dynamically, with error checking. */ 69 /* extern t *XMALLOC (typename t); */ 70 # define XMALLOC(t) ((t *) xmalloc (sizeof (t))) 71 72 /* Allocate memory for N elements of type T, with error checking. */ 73 /* extern t *XNMALLOC (size_t n, typename t); */ 74 # define XNMALLOC(n, t) \ 75 ((t *) (sizeof (t) == 1 ? xmalloc (n) : xnmalloc (n, sizeof (t)))) 76 77 /* Allocate an object of type T dynamically, with error checking, 78 and zero it. */ 79 /* extern t *XZALLOC (typename t); */ 80 # define XZALLOC(t) ((t *) xzalloc (sizeof (t))) 81 82 /* Allocate memory for N elements of type T, with error checking, 83 and zero it. */ 84 /* extern t *XCALLOC (size_t n, typename t); */ 85 # define XCALLOC(n, t) \ 86 ((t *) (sizeof (t) == 1 ? xzalloc (n) : xcalloc (n, sizeof (t)))) 87 88 89 # if HAVE_INLINE 90 # define static_inline static inline 91 # else 92 void *xnmalloc (size_t n, size_t s) 93 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2)); 94 void *xnrealloc (void *p, size_t n, size_t s) 95 _GL_ATTRIBUTE_ALLOC_SIZE ((2, 3)); 96 void *x2nrealloc (void *p, size_t *pn, size_t s); 97 char *xcharalloc (size_t n) 98 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1)); 99 # endif 100 101 # ifdef static_inline 102 103 /* Allocate an array of N objects, each with S bytes of memory, 104 dynamically, with error checking. S must be nonzero. */ 105 106 static_inline void *xnmalloc (size_t n, size_t s) 107 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1, 2)); 108 static_inline void * 109 xnmalloc (size_t n, size_t s) 110 { 111 if (xalloc_oversized (n, s)) 112 xalloc_die (); 113 return xmalloc (n * s); 114 } 115 116 /* Change the size of an allocated block of memory P to an array of N 117 objects each of S bytes, with error checking. S must be nonzero. */ 118 119 static_inline void *xnrealloc (void *p, size_t n, size_t s) 120 _GL_ATTRIBUTE_ALLOC_SIZE ((2, 3)); 121 static_inline void * 122 xnrealloc (void *p, size_t n, size_t s) 123 { 124 if (xalloc_oversized (n, s)) 125 xalloc_die (); 126 return xrealloc (p, n * s); 127 } 128 129 /* If P is null, allocate a block of at least *PN such objects; 130 otherwise, reallocate P so that it contains more than *PN objects 131 each of S bytes. *PN must be nonzero unless P is null, and S must 132 be nonzero. Set *PN to the new number of objects, and return the 133 pointer to the new block. *PN is never set to zero, and the 134 returned pointer is never null. 135 136 Repeated reallocations are guaranteed to make progress, either by 137 allocating an initial block with a nonzero size, or by allocating a 138 larger block. 139 140 In the following implementation, nonzero sizes are increased by a 141 factor of approximately 1.5 so that repeated reallocations have 142 O(N) overall cost rather than O(N**2) cost, but the 143 specification for this function does not guarantee that rate. 144 145 Here is an example of use: 146 147 int *p = NULL; 148 size_t used = 0; 149 size_t allocated = 0; 150 151 void 152 append_int (int value) 153 { 154 if (used == allocated) 155 p = x2nrealloc (p, &allocated, sizeof *p); 156 p[used++] = value; 157 } 158 159 This causes x2nrealloc to allocate a block of some nonzero size the 160 first time it is called. 161 162 To have finer-grained control over the initial size, set *PN to a 163 nonzero value before calling this function with P == NULL. For 164 example: 165 166 int *p = NULL; 167 size_t used = 0; 168 size_t allocated = 0; 169 size_t allocated1 = 1000; 170 171 void 172 append_int (int value) 173 { 174 if (used == allocated) 175 { 176 p = x2nrealloc (p, &allocated1, sizeof *p); 177 allocated = allocated1; 178 } 179 p[used++] = value; 180 } 181 182 */ 183 184 static_inline void * 185 x2nrealloc (void *p, size_t *pn, size_t s) 186 { 187 size_t n = *pn; 188 189 if (! p) 190 { 191 if (! n) 192 { 193 /* The approximate size to use for initial small allocation 194 requests, when the invoking code specifies an old size of 195 zero. This is the largest "small" request for the GNU C 196 library malloc. */ 197 enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 }; 198 199 n = DEFAULT_MXFAST / s; 200 n += !n; 201 } 202 } 203 else 204 { 205 /* Set N = ceil (1.5 * N) so that progress is made if N == 1. 206 Check for overflow, so that N * S stays in size_t range. 207 The check is slightly conservative, but an exact check isn't 208 worth the trouble. */ 209 if ((size_t) -1 / 3 * 2 / s <= n) 210 xalloc_die (); 211 n += (n + 1) / 2; 212 } 213 214 *pn = n; 215 return xrealloc (p, n * s); 216 } 217 218 /* Return a pointer to a new buffer of N bytes. This is like xmalloc, 219 except it returns char *. */ 220 221 static_inline char *xcharalloc (size_t n) 222 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((1)); 223 static_inline char * 224 xcharalloc (size_t n) 225 { 226 return XNMALLOC (n, char); 227 } 228 229 # endif 230 231 # ifdef __cplusplus 232 } 233 234 /* C++ does not allow conversions from void * to other pointer types 235 without a cast. Use templates to work around the problem when 236 possible. */ 237 238 template <typename T> inline T * 239 xrealloc (T *p, size_t s) 240 { 241 return (T *) xrealloc ((void *) p, s); 242 } 243 244 template <typename T> inline T * 245 xnrealloc (T *p, size_t n, size_t s) 246 { 247 return (T *) xnrealloc ((void *) p, n, s); 248 } 249 250 template <typename T> inline T * 251 x2realloc (T *p, size_t *pn) 252 { 253 return (T *) x2realloc ((void *) p, pn); 254 } 255 256 template <typename T> inline T * 257 x2nrealloc (T *p, size_t *pn, size_t s) 258 { 259 return (T *) x2nrealloc ((void *) p, pn, s); 260 } 261 262 template <typename T> inline T * 263 xmemdup (T const *p, size_t s) 264 { 265 return (T *) xmemdup ((void const *) p, s); 266 } 267 268 # endif 269 270 271 #endif /* !XALLOC_H_ */ 272