/* xmalloc.c -- malloc with out of memory checking

   Copyright (C) 1990-2000, 2002-2006, 2008-2025 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

   the Free Software Foundation, either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   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, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

#define XALLOC_INLINE _GL_EXTERN_INLINE

#include "xalloc.h"

#include "ialloc.h"

#include "minmax.h"

#include <stdckdint.h>

#include <stdlib.h>

#include <stdint.h>

#include <string.h>

static void * _GL_ATTRIBUTE_PURE

check_nonnull (void *p)

{

  if (!p)

    xalloc_die ();

  return p;

}

/* Allocate S bytes of memory dynamically, with error checking.  */

void *

xmalloc (size_t s)

{

  return check_nonnull (malloc (s));

}

void *

ximalloc (idx_t s)

{

  return check_nonnull (imalloc (s));

}

char *

xcharalloc (size_t n)

{

  return XNMALLOC (n, char);

}

/* Change the size of an allocated block of memory P to S bytes,

   with error checking.  */

void *

xrealloc (void *p, size_t s)

{

  void *r = realloc (p, s);

  if (!r)

    xalloc_die ();

  return r;

}

void *

xirealloc (void *p, idx_t s)

{

  return check_nonnull (irealloc (p, s));

}

/* Change the size of an allocated block of memory P to an array of N

   objects each of S bytes, with error checking.  */

void *

xreallocarray (void *p, size_t n, size_t s)

{

  void *r = reallocarray (p, n, s);

  if (!r)

    xalloc_die ();

  return r;

}

void *

xireallocarray (void *p, idx_t n, idx_t s)

{

  return check_nonnull (ireallocarray (p, n, s));

}

/* Allocate an array of N objects, each with S bytes of memory,

   dynamically, with error checking.  S must be nonzero.  */

void *

xnmalloc (size_t n, size_t s)

{

  return xreallocarray (NULL, n, s);

}

void *

xinmalloc (idx_t n, idx_t s)

{

  return xireallocarray (NULL, n, s);

}

/* If P is null, allocate a block of at least *PS bytes; otherwise,

   reallocate P so that it contains more than *PS bytes.  *PS must be

   nonzero unless P is null.  Set *PS to the new block's size, and

   return the pointer to the new block.  *PS is never set to zero, and

   the returned pointer is never null.  */

void *

x2realloc (void *p, size_t *ps)

{

  return x2nrealloc (p, ps, 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.  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 increased by a

   factor of approximately 1.5 so that repeated reallocations have

   O(N) overall cost rather than O(N**2) cost, but the

   specification for this function does not guarantee that rate.

   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;

       }

   */

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.  This is the largest "small" request for the GNU C

             library malloc.  */

          enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };

          n = DEFAULT_MXFAST / s;

          n += !n;

        }

    }

  else

    {

      /* Set N = floor (1.5 * N) + 1 to make progress even if N == 0.  */

      if (ckd_add (&n, n, (n >> 1) + 1))

        xalloc_die ();

    }

  p = xreallocarray (p, n, s);

  *pn = n;

  return p;

}

/* Grow PA, which points to an array of *PN items, and return the

   location of the reallocated array, updating *PN to reflect its

   new size.  The new array will contain at least N_INCR_MIN more

   items, but will not contain more than N_MAX items total.

   S is the size of each item, in bytes.

   S and N_INCR_MIN must be positive.  *PN must be

   nonnegative.  If N_MAX is -1, it is treated as if it were

   infinity.

   If PA is null, then allocate a new array instead of reallocating

   the old one.

   Thus, to grow an array A without saving its old contents, do

   { free (A); A = xpalloc (NULL, &AITEMS, ...); }.  */

void *

xpalloc (void *pa, idx_t *pn, idx_t n_incr_min, ptrdiff_t n_max, idx_t s)

{

  idx_t n0 = *pn;

  /* The approximate size to use for initial small allocation

     requests.  This is the largest "small" request for the GNU C

     library malloc.  */

  enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };

  /* If the array is tiny, grow it to about (but no greater than)

     DEFAULT_MXFAST bytes.  Otherwise, grow it by about 50%.

     Adjust the growth according to three constraints: N_INCR_MIN,

     N_MAX, and what the C language can represent safely.  */

  idx_t n;

  if (ckd_add (&n, n0, n0 >> 1))

    n = IDX_MAX;

  if (0 <= n_max && n_max < n)

    n = n_max;

  /* NBYTES is of a type suitable for holding the count of bytes in an object.

     This is typically idx_t, but it should be size_t on (theoretical?)

     platforms where SIZE_MAX < IDX_MAX so xpalloc does not pass

     values greater than SIZE_MAX to xrealloc.  */

#if IDX_MAX <= SIZE_MAX

  idx_t nbytes;

#else

  size_t nbytes;

#endif

  idx_t adjusted_nbytes

    = (ckd_mul (&nbytes, n, s)

       ? MIN (IDX_MAX, SIZE_MAX)

       : nbytes < DEFAULT_MXFAST ? DEFAULT_MXFAST : 0);

  if (adjusted_nbytes)

    {

      n = adjusted_nbytes / s;

      nbytes = adjusted_nbytes - adjusted_nbytes % s;

    }

  if (! pa)

    *pn = 0;

  if (n - n0 < n_incr_min

      && (ckd_add (&n, n0, n_incr_min)

          || (0 <= n_max && n_max < n)

          || ckd_mul (&nbytes, n, s)))

    xalloc_die ();

  pa = xrealloc (pa, nbytes);

  *pn = n;

  return pa;

}

/* 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 xcalloc (s, 1);

}

void *

xizalloc (idx_t s)

{

  return xicalloc (s, 1);

}

/* Allocate zeroed memory for N elements of S bytes, with error

   checking.  S must be nonzero.  */

void *

xcalloc (size_t n, size_t s)

{

  return check_nonnull (calloc (n, s));

}

void *

xicalloc (idx_t n, idx_t s)

{

  return check_nonnull (icalloc (n, s));

}

/* 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);

}

void *

ximemdup (void const *p, idx_t s)

{

  return memcpy (ximalloc (s), p, s);

}

/* Clone an object P of size S, with error checking.  Append

   a terminating NUL byte.  */

char *

ximemdup0 (void const *p, idx_t s)

{

  char *result = ximalloc (s + 1);

  result[s] = 0;

  return memcpy (result, p, s);

}

/* Clone STRING.  */

char *

xstrdup (char const *string)

{

  return xmemdup (string, strlen (string) + 1);

}