X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fxmalloc.c;h=9b7a948c2f18bc342294088ecbe2d2ab94f84ca6;hb=f239ee68d0f2d53e88890049e3f13c971b6ad8f9;hp=a595fe32bdd1a729abc1b332c9d666a484affc11;hpb=28d52bab31fb8b4495c260046b304864d4732cef;p=gnulib.git diff --git a/lib/xmalloc.c b/lib/xmalloc.c index a595fe32b..9b7a948c2 100644 --- a/lib/xmalloc.c +++ b/lib/xmalloc.c @@ -1,7 +1,7 @@ /* xmalloc.c -- malloc with out of memory checking - Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 2003, - 1999, 2000, 2002, 2003 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 @@ -23,95 +23,167 @@ #include "xalloc.h" -#include #include #include -#include "gettext.h" -#define _(msgid) gettext (msgid) -#define N_(msgid) msgid - -#include "error.h" -#include "exitfail.h" - #ifndef SIZE_MAX # define SIZE_MAX ((size_t) -1) #endif -#ifndef HAVE_MALLOC -"you must run the autoconf test for a GNU libc compatible malloc" -#endif - -#ifndef HAVE_REALLOC -"you must run the autoconf test for a GNU libc compatible realloc" -#endif - -/* If non NULL, call this function when memory is exhausted. */ -void (*xalloc_fail_func) (void) = 0; - -/* Return true if array of N objects, each of size S, cannot exist due - to arithmetic overflow. S must be nonzero. */ - -static inline bool -array_size_overflow (size_t n, size_t s) -{ - return SIZE_MAX / s < n; -} - -/* 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"); - -void -xalloc_die (void) -{ - if (xalloc_fail_func) - (*xalloc_fail_func) (); - error (exit_failure, 0, "%s", _(xalloc_msg_memory_exhausted)); - /* The `noreturn' cannot be given to error, since it may return if - its first argument is 0. To help compilers understand the - xalloc_die does terminate, call abort. */ - abort (); -} - /* Allocate an array of N objects, each with S bytes of memory, dynamically, with error checking. S must be nonzero. */ -inline void * -xnmalloc (size_t n, size_t s) +static inline void * +xnmalloc_inline (size_t n, size_t s) { void *p; - if (array_size_overflow (n, s) || ! (p = malloc (n * s))) + if (xalloc_oversized (n, s) || (! (p = malloc (n * s)) && n != 0)) xalloc_die (); return p; } +void * +xnmalloc (size_t n, size_t s) +{ + return xnmalloc_inline (n, s); +} + /* Allocate N bytes of memory dynamically, with error checking. */ void * xmalloc (size_t n) { - return xnmalloc (n, 1); + 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. */ -inline void * -xnrealloc (void *p, size_t n, size_t s) +static inline void * +xnrealloc_inline (void *p, size_t n, size_t s) { - if (array_size_overflow (n, s) || ! (p = realloc (p, n * 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. */ void * xrealloc (void *p, size_t n) { - return xnrealloc (p, n, 1); + return xnrealloc_inline (p, n, 1); +} + + +/* 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. @@ -133,7 +205,7 @@ xcalloc (size_t n, size_t s) void *p; /* Test for overflow, since some calloc implementations don't have proper overflow checks. */ - if (array_size_overflow (n, s) || ! (p = calloc (n, s))) + if (xalloc_oversized (n, s) || (! (p = calloc (n, s)) && n != 0)) xalloc_die (); return p; }