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author | Jim Meyering <jim@meyering.net> | 2003-10-31 13:41:44 +0000 |
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committer | Jim Meyering <jim@meyering.net> | 2003-10-31 13:41:44 +0000 |
commit | 6a9591f5b8a33fc0d332b812b52357be8a1ed79e (patch) | |
tree | 3fa4cc83c02bbbb347f24576a863c12685f9cfc9 /lib/xmalloc.c | |
parent | 4fc19cfd41ab02beac86b0395414fdac5f03587b (diff) | |
download | coreutils-6a9591f5b8a33fc0d332b812b52357be8a1ed79e.tar.xz |
Update from gnulib.
Diffstat (limited to 'lib/xmalloc.c')
-rw-r--r-- | lib/xmalloc.c | 144 |
1 files changed, 125 insertions, 19 deletions
diff --git a/lib/xmalloc.c b/lib/xmalloc.c index a595fe32b..20d85d83a 100644 --- a/lib/xmalloc.c +++ b/lib/xmalloc.c @@ -23,7 +23,6 @@ #include "xalloc.h" -#include <stdbool.h> #include <stdlib.h> #include <string.h> @@ -49,15 +48,6 @@ /* 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"); @@ -77,41 +67,157 @@ xalloc_die (void) /* 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))) 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))) 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 used = 0; + size 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 used = 0; + size allocated = 0; + size 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 +239,7 @@ 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))) xalloc_die (); return p; } |