/* Copyright (c) 2000, 2025, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License, version 2.0,

   as published by the Free Software Foundation.

   This program is designed to work with certain software (including

   but not limited to OpenSSL) that is licensed under separate terms,

   as designated in a particular file or component or in included license

   documentation.  The authors of MySQL hereby grant you an additional

   permission to link the program and your derivative works with the

   separately licensed software that they have either included with

   the program or referenced in the documentation.

   Without limiting anything contained in the foregoing, this file,

   which is part of C Driver for MySQL (Connector/C), is also subject to the

   Universal FOSS Exception, version 1.0, a copy of which can be found at

   http://oss.oracle.com/licenses/universal-foss-exception.

   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, version 2.0, 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

/**

  @file mysys/my_once.cc

*/

/* Not MT-SAFE */

#include <sys/types.h>

#include <cerrno>

#include <cstdlib>

#include <cstring>

#include "my_dbug.h"

#include "my_inttypes.h"

#include "my_pointer_arithmetic.h"

#include "my_sys.h"

#include "my_thread_local.h"

#include "mysys/my_static.h"

#include "mysys_err.h"

/*

  Alloc for things we don't nend to free run-time (that only

  should be free'd on exit)

  SYNOPSIS

    my_once_alloc()

      Size

      MyFlags

  NOTES

    No DBUG_TRACE... here to get smaller dbug-startup

*/

void *my_once_alloc(size_t Size, myf MyFlags) {

  size_t get_size, max_left;

  uchar *point;

  USED_MEM *next;

  USED_MEM **prev;

  Size = ALIGN_SIZE(Size);

  prev = &my_once_root_block;

  max_left = 0;

  for (next = my_once_root_block; next && next->left < Size;

       next = next->next) {

    if (next->left > max_left) max_left = next->left;

    prev = &next->next;

  }

  if (!next) { /* Time to alloc new block */

    get_size = Size + ALIGN_SIZE(sizeof(USED_MEM));

    if (max_left * 4 < my_once_extra && get_size < my_once_extra)

      get_size = my_once_extra; /* Normal alloc */

    if ((next = (USED_MEM *)malloc(get_size)) == nullptr) {

      set_my_errno(errno);

      if (MyFlags & (MY_FAE + MY_WME))

        my_error(EE_OUTOFMEMORY, MYF(ME_FATALERROR), get_size);

      return ((uchar *)nullptr);

    }

    DBUG_PRINT("test", ("my_once_malloc %lu byte malloced", (ulong)get_size));

    next->next = nullptr;

    next->size = (uint)get_size;

    next->left = (uint)(get_size - ALIGN_SIZE(sizeof(USED_MEM)));

    *prev = next;

  }

  point = (uchar *)((char *)next + (next->size - next->left));

  next->left -= (uint)Size;

  if (MyFlags & MY_ZEROFILL) memset(point, 0, Size);

  return ((void *)point);

} /* my_once_alloc */

char *my_once_strdup(const char *src, myf myflags) {

  const size_t len = strlen(src) + 1;

  auto *dst = static_cast<uchar *>(my_once_alloc(len, myflags));

  if (dst) memcpy(dst, src, len);

  return (char *)dst;

}

void *my_once_memdup(const void *src, size_t len, myf myflags) {

  auto *dst = static_cast<uchar *>(my_once_alloc(len, myflags));

  if (dst) memcpy(dst, src, len);

  return dst;

}

/*

  Deallocate everything that was allocated with my_once_alloc

  SYNOPSIS

    my_once_free()

*/

void my_once_free() {

  USED_MEM *next, *old;

  DBUG_TRACE;

  for (next = my_once_root_block; next;) {

    old = next;

    next = next->next;

    free((uchar *)old);

  }

  my_once_root_block = nullptr;

} /* my_once_free */