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Diffstat (limited to 'lib/malloca.h')
| -rw-r--r-- | lib/malloca.h | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/lib/malloca.h b/lib/malloca.h new file mode 100644 index 0000000..b0c78a3 --- /dev/null +++ b/lib/malloca.h @@ -0,0 +1,136 @@ +/* -*- buffer-read-only: t -*- vi: set ro: */ +/* DO NOT EDIT! GENERATED AUTOMATICALLY! */ +/* Safe automatic memory allocation. + Copyright (C) 2003-2007, 2009-2010 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 2003. + + 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, 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 _MALLOCA_H +#define _MALLOCA_H + +#include <alloca.h> +#include <stddef.h> +#include <stdlib.h> + + +#ifdef __cplusplus +extern "C" { +#endif + + +/* safe_alloca(N) is equivalent to alloca(N) when it is safe to call + alloca(N); otherwise it returns NULL. It either returns N bytes of + memory allocated on the stack, that lasts until the function returns, + or NULL. + Use of safe_alloca should be avoided: + - inside arguments of function calls - undefined behaviour, + - in inline functions - the allocation may actually last until the + calling function returns. +*/ +#if HAVE_ALLOCA +/* The OS usually guarantees only one guard page at the bottom of the stack, + and a page size can be as small as 4096 bytes. So we cannot safely + allocate anything larger than 4096 bytes. Also care for the possibility + of a few compiler-allocated temporary stack slots. + This must be a macro, not an inline function. */ +# define safe_alloca(N) ((N) < 4032 ? alloca (N) : NULL) +#else +# define safe_alloca(N) ((void) (N), NULL) +#endif + +/* malloca(N) is a safe variant of alloca(N). It allocates N bytes of + memory allocated on the stack, that must be freed using freea() before + the function returns. Upon failure, it returns NULL. */ +#if HAVE_ALLOCA +# define malloca(N) \ + ((N) < 4032 - sa_increment \ + ? (void *) ((char *) alloca ((N) + sa_increment) + sa_increment) \ + : mmalloca (N)) +#else +# define malloca(N) \ + mmalloca (N) +#endif +extern void * mmalloca (size_t n); + +/* Free a block of memory allocated through malloca(). */ +#if HAVE_ALLOCA +extern void freea (void *p); +#else +# define freea free +#endif + +/* nmalloca(N,S) is an overflow-safe variant of malloca (N * S). + It allocates an array of N objects, each with S bytes of memory, + on the stack. S must be positive and N must be nonnegative. + The array must be freed using freea() before the function returns. */ +#if 1 +/* Cf. the definition of xalloc_oversized. */ +# define nmalloca(n, s) \ + ((n) > (size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) \ + ? NULL \ + : malloca ((n) * (s))) +#else +extern void * nmalloca (size_t n, size_t s); +#endif + + +#ifdef __cplusplus +} +#endif + + +/* ------------------- Auxiliary, non-public definitions ------------------- */ + +/* Determine the alignment of a type at compile time. */ +#if defined __GNUC__ +# define sa_alignof __alignof__ +#elif defined __cplusplus + template <class type> struct sa_alignof_helper { char __slot1; type __slot2; }; +# define sa_alignof(type) offsetof (sa_alignof_helper<type>, __slot2) +#elif defined __hpux + /* Work around a HP-UX 10.20 cc bug with enums constants defined as offsetof + values. */ +# define sa_alignof(type) (sizeof (type) <= 4 ? 4 : 8) +#elif defined _AIX + /* Work around an AIX 3.2.5 xlc bug with enums constants defined as offsetof + values. */ +# define sa_alignof(type) (sizeof (type) <= 4 ? 4 : 8) +#else +# define sa_alignof(type) offsetof (struct { char __slot1; type __slot2; }, __slot2) +#endif + +enum +{ +/* The desired alignment of memory allocations is the maximum alignment + among all elementary types. */ + sa_alignment_long = sa_alignof (long), + sa_alignment_double = sa_alignof (double), +#if HAVE_LONG_LONG_INT + sa_alignment_longlong = sa_alignof (long long), +#endif + sa_alignment_longdouble = sa_alignof (long double), + sa_alignment_max = ((sa_alignment_long - 1) | (sa_alignment_double - 1) +#if HAVE_LONG_LONG_INT + | (sa_alignment_longlong - 1) +#endif + | (sa_alignment_longdouble - 1) + ) + 1, +/* The increment that guarantees room for a magic word must be >= sizeof (int) + and a multiple of sa_alignment_max. */ + sa_increment = ((sizeof (int) + sa_alignment_max - 1) / sa_alignment_max) * sa_alignment_max +}; + +#endif /* _MALLOCA_H */ |