mirror of https://gitee.com/openkylin/wget.git
341 lines
8.2 KiB
C
341 lines
8.2 KiB
C
/* xmalloc.c -- malloc with out of memory checking
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Copyright (C) 1990-2000, 2002-2006, 2008-2023 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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#define XALLOC_INLINE _GL_EXTERN_INLINE
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#include "xalloc.h"
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#include "ialloc.h"
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#include "minmax.h"
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#include <stdckdint.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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static void * _GL_ATTRIBUTE_PURE
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nonnull (void *p)
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{
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if (!p)
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xalloc_die ();
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return p;
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}
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/* Allocate S bytes of memory dynamically, with error checking. */
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void *
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xmalloc (size_t s)
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{
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return nonnull (malloc (s));
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}
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void *
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ximalloc (idx_t s)
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{
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return nonnull (imalloc (s));
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}
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char *
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xcharalloc (size_t n)
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{
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return XNMALLOC (n, char);
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}
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/* Change the size of an allocated block of memory P to S bytes,
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with error checking. */
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void *
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xrealloc (void *p, size_t s)
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{
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void *r = realloc (p, s);
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if (!r && (!p || s))
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xalloc_die ();
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return r;
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}
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void *
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xirealloc (void *p, idx_t s)
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{
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return nonnull (irealloc (p, s));
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}
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/* Change the size of an allocated block of memory P to an array of N
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objects each of S bytes, with error checking. */
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void *
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xreallocarray (void *p, size_t n, size_t s)
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{
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void *r = reallocarray (p, n, s);
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if (!r && (!p || (n && s)))
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xalloc_die ();
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return r;
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}
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void *
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xireallocarray (void *p, idx_t n, idx_t s)
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{
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return nonnull (ireallocarray (p, n, s));
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}
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/* Allocate an array of N objects, each with S bytes of memory,
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dynamically, with error checking. S must be nonzero. */
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void *
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xnmalloc (size_t n, size_t s)
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{
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return xreallocarray (NULL, n, s);
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}
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void *
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xinmalloc (idx_t n, idx_t s)
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{
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return xireallocarray (NULL, n, s);
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}
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/* If P is null, allocate a block of at least *PS bytes; otherwise,
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reallocate P so that it contains more than *PS bytes. *PS must be
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nonzero unless P is null. Set *PS to the new block's size, and
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return the pointer to the new block. *PS is never set to zero, and
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the returned pointer is never null. */
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void *
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x2realloc (void *p, size_t *ps)
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{
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return x2nrealloc (p, ps, 1);
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}
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/* If P is null, allocate a block of at least *PN such objects;
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otherwise, reallocate P so that it contains more than *PN objects
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each of S bytes. S must be nonzero. Set *PN to the new number of
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objects, and return the pointer to the new block. *PN is never set
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to zero, and the returned pointer is never null.
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Repeated reallocations are guaranteed to make progress, either by
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allocating an initial block with a nonzero size, or by allocating a
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larger block.
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In the following implementation, nonzero sizes are increased by a
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factor of approximately 1.5 so that repeated reallocations have
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O(N) overall cost rather than O(N**2) cost, but the
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specification for this function does not guarantee that rate.
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Here is an example of use:
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int *p = NULL;
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size_t used = 0;
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size_t allocated = 0;
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void
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append_int (int value)
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{
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if (used == allocated)
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p = x2nrealloc (p, &allocated, sizeof *p);
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p[used++] = value;
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}
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This causes x2nrealloc to allocate a block of some nonzero size the
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first time it is called.
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To have finer-grained control over the initial size, set *PN to a
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nonzero value before calling this function with P == NULL. For
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example:
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int *p = NULL;
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size_t used = 0;
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size_t allocated = 0;
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size_t allocated1 = 1000;
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void
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append_int (int value)
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{
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if (used == allocated)
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{
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p = x2nrealloc (p, &allocated1, sizeof *p);
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allocated = allocated1;
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}
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p[used++] = value;
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}
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*/
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void *
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x2nrealloc (void *p, size_t *pn, size_t s)
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{
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size_t n = *pn;
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if (! p)
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{
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if (! n)
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{
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/* The approximate size to use for initial small allocation
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requests, when the invoking code specifies an old size of
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zero. This is the largest "small" request for the GNU C
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library malloc. */
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enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };
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n = DEFAULT_MXFAST / s;
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n += !n;
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}
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}
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else
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{
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/* Set N = floor (1.5 * N) + 1 to make progress even if N == 0. */
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if (ckd_add (&n, n, (n >> 1) + 1))
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xalloc_die ();
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}
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p = xreallocarray (p, n, s);
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*pn = n;
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return p;
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}
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/* Grow PA, which points to an array of *PN items, and return the
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location of the reallocated array, updating *PN to reflect its
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new size. The new array will contain at least N_INCR_MIN more
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items, but will not contain more than N_MAX items total.
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S is the size of each item, in bytes.
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S and N_INCR_MIN must be positive. *PN must be
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nonnegative. If N_MAX is -1, it is treated as if it were
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infinity.
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If PA is null, then allocate a new array instead of reallocating
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the old one.
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Thus, to grow an array A without saving its old contents, do
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{ free (A); A = xpalloc (NULL, &AITEMS, ...); }. */
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void *
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xpalloc (void *pa, idx_t *pn, idx_t n_incr_min, ptrdiff_t n_max, idx_t s)
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{
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idx_t n0 = *pn;
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/* The approximate size to use for initial small allocation
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requests. This is the largest "small" request for the GNU C
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library malloc. */
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enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };
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/* If the array is tiny, grow it to about (but no greater than)
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DEFAULT_MXFAST bytes. Otherwise, grow it by about 50%.
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Adjust the growth according to three constraints: N_INCR_MIN,
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N_MAX, and what the C language can represent safely. */
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idx_t n;
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if (ckd_add (&n, n0, n0 >> 1))
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n = IDX_MAX;
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if (0 <= n_max && n_max < n)
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n = n_max;
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/* NBYTES is of a type suitable for holding the count of bytes in an object.
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This is typically idx_t, but it should be size_t on (theoretical?)
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platforms where SIZE_MAX < IDX_MAX so xpalloc does not pass
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values greater than SIZE_MAX to xrealloc. */
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#if IDX_MAX <= SIZE_MAX
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idx_t nbytes;
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#else
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size_t nbytes;
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#endif
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idx_t adjusted_nbytes
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= (ckd_mul (&nbytes, n, s)
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? MIN (IDX_MAX, SIZE_MAX)
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: nbytes < DEFAULT_MXFAST ? DEFAULT_MXFAST : 0);
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if (adjusted_nbytes)
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{
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n = adjusted_nbytes / s;
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nbytes = adjusted_nbytes - adjusted_nbytes % s;
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}
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if (! pa)
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*pn = 0;
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if (n - n0 < n_incr_min
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&& (ckd_add (&n, n0, n_incr_min)
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|| (0 <= n_max && n_max < n)
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|| ckd_mul (&nbytes, n, s)))
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xalloc_die ();
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pa = xrealloc (pa, nbytes);
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*pn = n;
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return pa;
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}
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/* Allocate S bytes of zeroed memory dynamically, with error checking.
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There's no need for xnzalloc (N, S), since it would be equivalent
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to xcalloc (N, S). */
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void *
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xzalloc (size_t s)
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{
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return xcalloc (s, 1);
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}
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void *
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xizalloc (idx_t s)
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{
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return xicalloc (s, 1);
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}
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/* Allocate zeroed memory for N elements of S bytes, with error
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checking. S must be nonzero. */
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void *
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xcalloc (size_t n, size_t s)
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{
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return nonnull (calloc (n, s));
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}
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void *
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xicalloc (idx_t n, idx_t s)
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{
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return nonnull (icalloc (n, s));
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}
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/* Clone an object P of size S, with error checking. There's no need
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for xnmemdup (P, N, S), since xmemdup (P, N * S) works without any
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need for an arithmetic overflow check. */
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void *
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xmemdup (void const *p, size_t s)
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{
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return memcpy (xmalloc (s), p, s);
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}
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void *
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ximemdup (void const *p, idx_t s)
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{
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return memcpy (ximalloc (s), p, s);
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}
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/* Clone an object P of size S, with error checking. Append
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a terminating NUL byte. */
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char *
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ximemdup0 (void const *p, idx_t s)
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{
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char *result = ximalloc (s + 1);
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result[s] = 0;
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return memcpy (result, p, s);
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}
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/* Clone STRING. */
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char *
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xstrdup (char const *string)
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{
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return xmemdup (string, strlen (string) + 1);
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}
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