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author | Paul Eggert <eggert@cs.ucla.edu> | 2006-11-06 21:24:35 +0000 |
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committer | Paul Eggert <eggert@cs.ucla.edu> | 2006-11-06 21:24:35 +0000 |
commit | ac2a728a11acdae91051359487c52acc9d180a8e (patch) | |
tree | 609637805447a082b6621a4a4332d88c5888c640 /lib/xalloc.h | |
parent | 0c0219f84c3c29237187f0640248eef23c815900 (diff) | |
download | gnulib-ac2a728a11acdae91051359487c52acc9d180a8e.tar.gz |
* lib/xalloc.h (xnmalloc, xnrealloc, x2nrealloc): Now static
inline functions that are identical with the old xnmalloc_inline,
xnrealloc_inline, x2nrealloc_inline of lib/xmalloc.c. This is so
that we can avoid some unnecessary integer multiplications and
divisions in the common case where the element size is known at
compile time.
(XNMALLOC) [HAVE_INLINE]: Remove special case, which is no longer
needed.
(xnboundedmalloc): Remove.
(XMALLOC, XNMALLOC, XZALLOC, XCALLOC): Use lower-case letters for
arguments, for consistency with rest of this header.
(xcharalloc): Rewrite using XNMALLOC.
* lib/xmalloc.c (xnmalloc_inline, xnmalloc, xnrealloc_inline):
(xnrealloc, x2nrealloc_inline, x2nrealloc): Remove. The *_inline
versions have been moved to lib/xalloc.h and renamed to be the
non-*_inline versions.
(xmalloc, xrealloc): Implement without reference to the xnmalloc
and xnrealloc functions, since those functions are now inline and
now call us.
(x2realloc): Invoke x2realloc, not x2realloc_inline, to accommodate
renaming described above.
Diffstat (limited to 'lib/xalloc.h')
-rw-r--r-- | lib/xalloc.h | 160 |
1 files changed, 121 insertions, 39 deletions
diff --git a/lib/xalloc.h b/lib/xalloc.h index 6881ea678d..459e37a0ed 100644 --- a/lib/xalloc.h +++ b/lib/xalloc.h @@ -1,7 +1,7 @@ /* xalloc.h -- malloc with out-of-memory checking Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, - 1999, 2000, 2003, 2004 Free Software Foundation, Inc. + 1999, 2000, 2003, 2004, 2006 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 @@ -46,13 +46,10 @@ extern "C" { extern void xalloc_die (void) ATTRIBUTE_NORETURN; void *xmalloc (size_t s); -void *xnmalloc (size_t n, size_t s); void *xzalloc (size_t s); void *xcalloc (size_t n, size_t s); void *xrealloc (void *p, size_t s); -void *xnrealloc (void *p, size_t n, size_t s); void *x2realloc (void *p, size_t *pn); -void *x2nrealloc (void *p, size_t *pn, size_t s); void *xmemdup (void const *p, size_t s); char *xstrdup (char const *str); @@ -71,57 +68,142 @@ char *xstrdup (char const *str); # define xalloc_oversized(n, s) \ ((size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) < (n)) -/* In the following macros, T must be an elementary or structure/union or - typedef'ed type, or a pointer to such a type. To apply one of the - following macros to a function pointer or array type, you need to typedef - it first and use the typedef name. */ +/* Allocate an array of N objects, each with S bytes of memory, + dynamically, with error checking. S must be nonzero. */ -/* Allocate an object of type T dynamically, with error checking. */ -/* extern T *XMALLOC (typename T); */ -#define XMALLOC(T) \ - ((T *) xmalloc (sizeof (T))) - -/* Allocate memory for NMEMB elements of type T, with error checking. */ -/* extern T *XNMALLOC (size_t nmemb, typename T); */ -#if HAVE_INLINE -/* xnmalloc performs a division and multiplication by sizeof (T). Arrange to - perform the division at compile-time and the multiplication with a factor - known at compile-time. */ -# define XNMALLOC(N,T) \ - ((T *) (sizeof (T) == 1 \ - ? xmalloc (N) \ - : xnboundedmalloc(N, (size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / sizeof (T), sizeof (T)))) static inline void * -xnboundedmalloc (size_t n, size_t bound, size_t s) +xnmalloc (size_t n, size_t s) { - if (n > bound) + if (xalloc_oversized (n, s)) xalloc_die (); return xmalloc (n * s); } -#else -# define XNMALLOC(N,T) \ - ((T *) (sizeof (T) == 1 ? xmalloc (N) : xnmalloc (N, sizeof (T)))) -#endif + +/* 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 (void *p, size_t n, size_t s) +{ + if (xalloc_oversized (n, s)) + xalloc_die (); + return xrealloc (p, n * s); +} + +/* 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 (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_t) -1) / 2 / s < n) + xalloc_die (); + n *= 2; + } + + *pn = n; + return xrealloc (p, n * s); +} + +/* In the following macros, T must be an elementary or structure/union or + typedef'ed type, or a pointer to such a type. To apply one of the + following macros to a function pointer or array type, you need to typedef + it first and use the typedef name. */ + +/* Allocate an object of type T dynamically, with error checking. */ +/* extern t *XMALLOC (typename t); */ +#define XMALLOC(t) ((t *) xmalloc (sizeof (t))) + +/* Allocate memory for N elements of type T, with error checking. */ +/* extern t *XNMALLOC (size_t n, typename t); */ +#define XNMALLOC(n, t) ((t *) xnmalloc (n, sizeof (t))) /* Allocate an object of type T dynamically, with error checking, and zero it. */ -/* extern T *XZALLOC (typename T); */ -#define XZALLOC(T) \ - ((T *) xzalloc (sizeof (T))) +/* extern t *XZALLOC (typename t); */ +#define XZALLOC(t) ((t *) xzalloc (sizeof (t))) -/* Allocate memory for NMEMB elements of type T, with error checking, +/* Allocate memory for N elements of type T, with error checking, and zero it. */ -/* extern T *XCALLOC (size_t nmemb, typename T); */ -#define XCALLOC(N,T) \ - ((T *) xcalloc (N, sizeof (T))) +/* extern t *XCALLOC (size_t n, typename t); */ +#define XCALLOC(n, t) ((t *) xcalloc (n, sizeof (t))) /* Return a pointer to a new buffer of N bytes. This is like xmalloc, - except it returns char *. - xcharalloc (N) is equivalent to XNMALLOC (N, char). */ + except it returns char *. */ static inline char * xcharalloc (size_t n) { - return (char *) xmalloc (n); + return XNMALLOC (n, char); } # ifdef __cplusplus |