X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fxmalloc.c;h=9b7a948c2f18bc342294088ecbe2d2ab94f84ca6;hb=f239ee68d0f2d53e88890049e3f13c971b6ad8f9;hp=01ac54824815daf95d989a2b0ff3bfed5c6302bf;hpb=21e75a3758a09f92db813276fb7fd0db0e768f46;p=gnulib.git diff --git a/lib/xmalloc.c b/lib/xmalloc.c index 01ac54824..9b7a948c2 100644 --- a/lib/xmalloc.c +++ b/lib/xmalloc.c @@ -1,5 +1,7 @@ /* xmalloc.c -- malloc with out of memory checking - Copyright (C) 1990-1997, 98 Free Software Foundation, Inc. + + Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, + 1999, 2000, 2002, 2003, 2004 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 @@ -19,58 +21,31 @@ # include #endif -#include - -#if STDC_HEADERS -# include -#else -void *calloc (); -void *malloc (); -void *realloc (); -void free (); -#endif - -#if ENABLE_NLS -# include -# define _(Text) gettext (Text) -#else -# define textdomain(Domain) -# define _(Text) Text -#endif -#define N_(Text) Text - -#include "error.h" #include "xalloc.h" -#ifndef EXIT_FAILURE -# define EXIT_FAILURE 1 -#endif - -#ifndef HAVE_DONE_WORKING_MALLOC_CHECK -you must run the autoconf test for a properly working malloc -- see malloc.m4 -#endif +#include +#include -#ifndef HAVE_DONE_WORKING_REALLOC_CHECK -you must run the autoconf test for a properly working realloc -- see realloc.m4 +#ifndef SIZE_MAX +# define SIZE_MAX ((size_t) -1) #endif -/* Exit value when the requested amount of memory is not available. - The caller may set it to some other value. */ -int xalloc_exit_failure = EXIT_FAILURE; +/* Allocate an array of N objects, each with S bytes of memory, + dynamically, with error checking. S must be nonzero. */ -/* If non NULL, call this function when memory is exhausted. */ -void (*xalloc_fail_func) () = 0; - -/* If XALLOC_FAIL_FUNC is NULL, or does return, display this message - before exiting when memory is exhausted. Goes through gettext. */ -char *const xalloc_msg_memory_exhausted = N_("Memory exhausted"); +static inline void * +xnmalloc_inline (size_t n, size_t s) +{ + void *p; + if (xalloc_oversized (n, s) || (! (p = malloc (n * s)) && n != 0)) + xalloc_die (); + return p; +} -static void -xalloc_fail (void) +void * +xnmalloc (size_t n, size_t s) { - if (xalloc_fail_func) - (*xalloc_fail_func) (); - error (xalloc_exit_failure, 0, xalloc_msg_memory_exhausted); + return xnmalloc_inline (n, s); } /* Allocate N bytes of memory dynamically, with error checking. */ @@ -78,36 +53,169 @@ xalloc_fail (void) void * xmalloc (size_t n) { - void *p; + return xnmalloc_inline (n, 1); +} + +/* 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. */ - p = malloc (n); - if (p == 0) - xalloc_fail (); +static inline void * +xnrealloc_inline (void *p, size_t n, size_t s) +{ + if (xalloc_oversized (n, s) || (! (p = realloc (p, n * s)) && n != 0)) + xalloc_die (); return p; } +void * +xnrealloc (void *p, size_t n, size_t s) +{ + return xnrealloc_inline (p, n, s); +} + /* Change the size of an allocated block of memory P to N bytes, - with error checking. - If P is NULL, run xmalloc. */ + with error checking. */ void * xrealloc (void *p, size_t n) { - p = realloc (p, n); - if (p == 0) - xalloc_fail (); - return p; + return xnrealloc_inline (p, n, 1); } -/* Allocate memory for N elements of S bytes, with error checking. */ + +/* 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 doubled so that + repeated reallocations have O(N log N) overall cost rather than + O(N**2) cost, but the specification for this function does not + guarantee that sizes are doubled. + + 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_inline (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 + { + if (SIZE_MAX / 2 / s < n) + xalloc_die (); + n *= 2; + } + + *pn = n; + return xrealloc (p, n * s); +} + +void * +x2nrealloc (void *p, size_t *pn, size_t s) +{ + return x2nrealloc_inline (p, pn, s); +} + +/* If P is null, allocate a block of at least *PN bytes; otherwise, + reallocate P so that it contains more than *PN bytes. *PN must be + nonzero unless P is null. Set *PN to the new block's size, and + return the pointer to the new block. *PN is never set to zero, and + the returned pointer is never null. */ + +void * +x2realloc (void *p, size_t *pn) +{ + return x2nrealloc_inline (p, pn, 1); +} + +/* Allocate S bytes of zeroed memory dynamically, with error checking. + There's no need for xnzalloc (N, S), since it would be equivalent + to xcalloc (N, S). */ + +void * +xzalloc (size_t s) +{ + return memset (xmalloc (s), 0, s); +} + +/* Allocate zeroed memory for N elements of S bytes, with error + checking. S must be nonzero. */ void * xcalloc (size_t n, size_t s) { void *p; - - p = calloc (n, s); - if (p == 0) - xalloc_fail (); + /* Test for overflow, since some calloc implementations don't have + proper overflow checks. */ + if (xalloc_oversized (n, s) || (! (p = calloc (n, s)) && n != 0)) + xalloc_die (); return p; } + +/* Clone an object P of size S, with error checking. There's no need + for xnclone (P, N, S), since xclone (P, N * S) works without any + need for an arithmetic overflow check. */ + +void * +xclone (void const *p, size_t s) +{ + return memcpy (xmalloc (s), p, s); +}