/* xalloc.h -- malloc with out-of-memory checking Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2003, 2004, 2006, 2007 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 2, 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #ifndef XALLOC_H_ # define XALLOC_H_ # include <stddef.h> # ifdef __cplusplus extern "C" { # endif # ifndef __attribute__ # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__ # define __attribute__(x) # endif # endif # ifndef ATTRIBUTE_NORETURN # define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__)) # 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 void xalloc_die (void) ATTRIBUTE_NORETURN; void *xmalloc (size_t s); void *xzalloc (size_t s); void *xcalloc (size_t n, size_t s); void *xrealloc (void *p, size_t s); void *x2realloc (void *p, size_t *pn); void *xmemdup (void const *p, size_t s); char *xstrdup (char const *str); /* Return 1 if an array of N objects, each of size S, cannot exist due to size arithmetic overflow. S must be positive and N must be nonnegative. This is a macro, not an inline function, so that it works correctly even when SIZE_MAX < N. By gnulib convention, SIZE_MAX represents overflow in size calculations, so the conservative dividend to use here is SIZE_MAX - 1, since SIZE_MAX might represent an overflowed value. However, malloc (SIZE_MAX) fails on all known hosts where sizeof (ptrdiff_t) <= sizeof (size_t), so do not bother to test for exactly-SIZE_MAX allocations on such hosts; this avoids a test and branch when S is known to be 1. */ # define xalloc_oversized(n, s) \ ((size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) < (n)) /* 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)))) # if HAVE_INLINE # define static_inline static inline # else void *xnmalloc (size_t n, size_t s); void *xnrealloc (void *p, size_t n, size_t s); void *x2nrealloc (void *p, size_t *pn, size_t s); char *xcharalloc (size_t n); # endif # ifdef static_inline /* Allocate an array of N objects, each with S bytes of memory, dynamically, with error checking. S must be nonzero. */ static_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. */ static_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; } */ static_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. 64 bytes is the largest "small" request for the GNU C library malloc. */ enum { DEFAULT_MXFAST = 64 }; 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 *. */ static_inline char * xcharalloc (size_t n) { return XNMALLOC (n, char); } # endif # 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_ */