X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fxmalloc.c;h=c1632b96de5ebed31ecbd3a096b6e0822d9d6f63;hb=b00e860d80d31318069eafaa67c920f24deae638;hp=f989004bebcd739074164a63457e29bf07d89178;hpb=43e78b970f396160a887c9da94531569faeda8a0;p=gnulib.git diff --git a/lib/xmalloc.c b/lib/xmalloc.c index f989004be..c1632b96d 100644 --- a/lib/xmalloc.c +++ b/lib/xmalloc.c @@ -1,5 +1,7 @@ /* xmalloc.c -- malloc with out of memory checking - Copyright (C) 1990, 1991 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 @@ -12,54 +14,216 @@ 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ + along with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +#if HAVE_CONFIG_H +# include +#endif + +#include "xalloc.h" -#ifdef STDC_HEADERS #include -#else -char *malloc (); -char *realloc (); -void free (); +#include + +#ifndef SIZE_MAX +# define SIZE_MAX ((size_t) -1) #endif -void error (); +/* Allocate an array of N objects, each with S bytes of memory, + dynamically, with error checking. S must be nonzero. */ + +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; +} + +void * +xnmalloc (size_t n, size_t s) +{ + return xnmalloc_inline (n, s); +} /* Allocate N bytes of memory dynamically, with error checking. */ -char * -xmalloc (n) - unsigned n; +void * +xmalloc (size_t n) { - char *p; + return xnmalloc_inline (n, 1); +} - p = malloc (n); - if (p == 0) - /* Must exit with 2 for `cmp'. */ - error (2, 0, "virtual memory exhausted"); +/* 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_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. - If N is 0, run free and return NULL. */ + with error checking. */ -char * -xrealloc (p, n) - char *p; - unsigned n; +void * +xrealloc (void *p, size_t n) +{ + 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) { - if (p == 0) - return xmalloc (n); - if (n == 0) + size_t n = *pn; + + if (! p) { - free (p); - return 0; + 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; } - p = realloc (p, n); - if (p == 0) - /* Must exit with 2 for `cmp'. */ - error (2, 0, "virtual memory exhausted"); + + *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; + /* 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 xnmemdup (P, N, S), since xmemdup (P, N * S) works without any + need for an arithmetic overflow check. */ + +void * +xmemdup (void const *p, size_t s) +{ + return memcpy (xmalloc (s), p, s); +} + +/* Clone STRING. */ + +char * +xstrdup (char const *string) +{ + return xmemdup (string, strlen (string) + 1); +}