--- /dev/null
+/* Safe automatic memory allocation.
+ Copyright (C) 2003 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 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Specification. */
+#include "allocsa.h"
+
+/* The speed critical point in this file is freesa() applied to an alloca()
+ result: it must be fast, to match the speed of alloca(). The speed of
+ mallocsa() and freesa() in the other case are not critical, because they
+ are only invoked for big memory sizes. */
+
+#if HAVE_ALLOCA
+
+/* Store the mallocsa() results in a hash table. This is needed to reliably
+ distinguish a mallocsa() result and an alloca() result.
+
+ Although it is possible that the same pointer is returned by alloca() and
+ by mallocsa() at different times in the same application, it does not lead
+ to a bug in freesa(), because:
+ - Before a pointer returned by alloca() can point into malloc()ed memory,
+ the function must return, and once this has happened the programmer must
+ not call freesa() on it anyway.
+ - Before a pointer returned by mallocsa() can point into the stack, it
+ must be freed. The only function that can free it is freesa(), and
+ when freesa() frees it, it also removes it from the hash table. */
+
+#define MAGIC_NUMBER 0x1415fb4a
+#define MAGIC_SIZE sizeof (int)
+/* This is how the header info would look like without any alignment
+ considerations. */
+struct preliminary_header { void *next; char room[MAGIC_SIZE]; };
+/* But the header's size must be a multiple of sa_alignment_max. */
+#define HEADER_SIZE \
+ (((sizeof (struct preliminary_header) + sa_alignment_max - 1) / sa_alignment_max) * sa_alignment_max)
+struct header { void *next; char room[HEADER_SIZE - sizeof (struct preliminary_header) + MAGIC_SIZE]; };
+/* Verify that HEADER_SIZE == sizeof (struct header). */
+typedef int verify1[2 * (HEADER_SIZE == sizeof (struct header)) - 1];
+/* We make the hash table quite big, so that during lookups the probability
+ of empty hash buckets is quite high. There is no need to make the hash
+ table resizable, because when the hash table gets filled so much that the
+ lookup becomes slow, it means that the application has memory leaks. */
+#define HASH_TABLE_SIZE 257
+static void * mallocsa_results[HASH_TABLE_SIZE];
+
+#endif
+
+void *
+mallocsa (size_t n)
+{
+#if HAVE_ALLOCA
+ /* Allocate one more word, that serves as an indicator for malloc()ed
+ memory, so that freesa() of an alloca() result is fast. */
+ size_t nplus = n + HEADER_SIZE;
+
+ if (nplus >= n)
+ {
+ char *p = (char *) malloc (nplus);
+
+ if (p != NULL)
+ {
+ size_t slot;
+
+ p += HEADER_SIZE;
+
+ /* Put a magic number into the indicator word. */
+ ((int *) p)[-1] = MAGIC_NUMBER;
+
+ /* Enter p into the hash table. */
+ slot = (unsigned long) p % HASH_TABLE_SIZE;
+ ((struct header *) (p - HEADER_SIZE))->next = mallocsa_results[slot];
+ mallocsa_results[slot] = p;
+
+ return p;
+ }
+ }
+ /* Out of memory. */
+ return NULL;
+#else
+# if !MALLOC_0_IS_NONNULL
+ if (n == 0)
+ n = 1;
+# endif
+ return malloc (n);
+#endif
+}
+
+#if HAVE_ALLOCA
+void
+freesa (void *p)
+{
+ /* mallocsa() may have returned NULL. */
+ if (p != NULL)
+ {
+ /* Attempt to quickly distinguish the mallocsa() result - which has
+ a magic indicator word - and the alloca() result - which has an
+ uninitialized indicator word. It is for this test that sa_increment
+ additional bytes are allocated in the alloca() case. */
+ if (((int *) p)[-1] == MAGIC_NUMBER)
+ {
+ /* Looks like a mallocsa() result. To see whether it really is one,
+ perform a lookup in the hash table. */
+ size_t slot = (unsigned long) p % HASH_TABLE_SIZE;
+ void **chain = &mallocsa_results[slot];
+ for (; *chain != NULL;)
+ {
+ if (*chain == p)
+ {
+ /* Found it. Remove it from the hash table and free it. */
+ char *p_begin = (char *) p - HEADER_SIZE;
+ *chain = ((struct header *) p_begin)->next;
+ free (p_begin);
+ return;
+ }
+ chain = &((struct header *) ((char *) *chain - HEADER_SIZE))->next;
+ }
+ }
+ /* At this point, we know it was not a mallocsa() result. */
+ }
+}
+#endif
--- /dev/null
+/* Safe automatic memory allocation.
+ Copyright (C) 2003 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 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+#ifndef _ALLOCSA_H
+#define _ALLOCSA_H
+
+#include <alloca.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+/* 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) ((N), NULL)
+#endif
+
+/* allocsa(N) is a safe variant of alloca(N). It allocates N bytes of
+ memory allocated on the stack, that must be freed using freesa() before
+ the function returns. Upon failure, it returns NULL. */
+#if HAVE_ALLOCA
+# define allocsa(N) \
+ ((N) < 4032 - sa_increment \
+ ? (void *) ((char *) alloca ((N) + sa_increment) + sa_increment) \
+ : mallocsa (N))
+#else
+# define allocsa(N) \
+ mallocsa (N)
+#endif
+extern void * mallocsa (size_t n);
+
+/* Free a block of memory allocated through allocsa(). */
+#if HAVE_ALLOCA
+extern void freesa (void *p);
+#else
+# define freesa free
+#endif
+
+/* Maybe we should also define a variant
+ nallocsa (size_t n, size_t s) - behaves like allocsa (n * s)
+ If this would be useful in your application. please speak up. */
+
+
+/* ------------------- 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)
+#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),
+#ifdef HAVE_LONG_LONG
+ sa_alignment_longlong = sa_alignof (long long),
+#endif
+#ifdef HAVE_LONG_DOUBLE
+ sa_alignment_longdouble = sa_alignof (long double),
+#endif
+ sa_alignment_max = ((sa_alignment_long - 1) | (sa_alignment_double - 1)
+#ifdef HAVE_LONG_LONG
+ | (sa_alignment_longlong - 1)
+#endif
+#ifdef HAVE_LONG_DOUBLE
+ | (sa_alignment_longdouble - 1)
+#endif
+ ) + 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 /* _ALLOCSA_H */
--- /dev/null
+/* Safe automatic memory allocation with out of memory checking.
+ Copyright (C) 2003 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 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Specification. */
+#include "xallocsa.h"
+
+#include "xalloc.h"
+
+void *
+xmallocsa (size_t n)
+{
+ void *p;
+
+ p = mallocsa (n);
+ if (p == NULL)
+ xalloc_die ();
+ return p;
+}
--- /dev/null
+/* Safe automatic memory allocation with out of memory checking.
+ Copyright (C) 2003 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 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+#ifndef _XALLOCSA_H
+#define _XALLOCSA_H
+
+#include "allocsa.h"
+
+/* xallocsa(N) is a checking safe variant of alloca(N). It allocates N bytes
+ of memory allocated on the stack, that must be freed using freesa() before
+ the function returns. Upon failure, it exits with an error message. */
+#if HAVE_ALLOCA
+# define xallocsa(N) \
+ ((N) < 4032 - sa_increment \
+ ? (void *) ((char *) alloca ((N) + sa_increment) + sa_increment) \
+ : xmallocsa (N))
+extern void * xmallocsa (size_t n);
+#else
+# define xallocsa(N) \
+ xmalloc (N)
+#endif
+
+/* Maybe we should also define a variant
+ xnallocsa (size_t n, size_t s) - behaves like xallocsa (n * s)
+ If this would be useful in your application. please speak up. */
+
+#endif /* _XALLOCSA_H */
--- /dev/null
+# allocasa.m4 serial 1
+dnl Copyright (C) 2003 Free Software Foundation, Inc.
+dnl This file is free software, distributed under the terms of the GNU
+dnl General Public License. As a special exception to the GNU General
+dnl Public License, this file may be distributed as part of a program
+dnl that contains a configuration script generated by Autoconf, under
+dnl the same distribution terms as the rest of that program.
+
+AC_DEFUN([gl_ALLOCSA],
+[
+ dnl Use the autoconf tests for alloca(), but not the AC_SUBSTed variables
+ dnl @ALLOCA@ and @LTALLOCA@.
+ AC_REQUIRE([gl_FUNC_ALLOCA])
+ AC_REQUIRE([gl_EEMALLOC])
+])
projects / thirdparty / gettext.git / commitdiff
