/* This file is part of GDBM, the GNU data base manager.

   Copyright (C) 2011-2025 Free Software Foundation, Inc.

   GDBM 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, or (at your option)

   any later version.

   GDBM 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 GDBM. If not, see <http://www.gnu.org/licenses/>.   */

#include "autoconf.h"

#include "gdbmdefs.h"

/* Read exactly SIZE bytes of data into BUFFER.  Return value is 0 on

   success, and -1 on error.  In the latter case, gdbm_errno is set to

   GDBM_FILE_EOF, if not enough data is available, and to

   GDBM_FILE_READ_ERROR, if a read error occurs. */

int

_gdbm_full_read (GDBM_FILE dbf, void *buffer, size_t size)

{

  char *ptr = buffer;

  while (size)

    {

      ssize_t rdbytes = gdbm_file_read (dbf, ptr, size);

      if (rdbytes == -1)

  {

    if (errno == EINTR)

      continue;

    if (gdbm_last_errno (dbf) == GDBM_NO_ERROR)

      GDBM_SET_ERRNO (dbf, GDBM_FILE_READ_ERROR, FALSE);

    return -1;

  }

      if (rdbytes == 0)

  {

    GDBM_SET_ERRNO (dbf, GDBM_FILE_EOF, FALSE);

    return -1;

  }

      ptr += rdbytes;

      size -= rdbytes;

    }

  return 0;

}

/* Write exactly SIZE bytes of data from BUFFER to DBF.  Return 0 on

   success, and -1 (setting gdbm_errno to GDBM_FILE_READ_ERROR) on error. */

int

_gdbm_full_write (GDBM_FILE dbf, void *buffer, size_t size)

{

  char *ptr = buffer;

  /* Invalidate file_size */

  dbf->file_size = -1;

  while (size)

    {

      ssize_t wrbytes = gdbm_file_write (dbf, ptr, size);

      if (wrbytes == -1)

  {

    if (errno == EINTR)

      continue;

    if (gdbm_last_errno (dbf) == GDBM_NO_ERROR)

      GDBM_SET_ERRNO (dbf, GDBM_FILE_WRITE_ERROR, TRUE);

    return -1;

  }

      if (wrbytes == 0)

  {

    errno = ENOSPC;

    GDBM_SET_ERRNO (dbf, GDBM_FILE_WRITE_ERROR, TRUE);

    return -1;

  }

      ptr += wrbytes;

      size -= wrbytes;

    }

  return 0;

}

/* Grow the disk file of DBF to SIZE bytes in length. Fill the

   newly allocated space with zeros. */

int

_gdbm_file_extend (GDBM_FILE dbf, off_t size)

{

  size_t page_size = sysconf (_SC_PAGESIZE);

  char *buf;

  off_t file_end;

  file_end = lseek (dbf->desc, 0, SEEK_END);

  if (!file_end)

    {

      GDBM_SET_ERRNO (dbf, GDBM_FILE_SEEK_ERROR, FALSE);

      return -1;

    }

  size -= file_end;

  if (size > 0)

    {

      if (size < page_size)

  page_size = size;

      buf = calloc (1, page_size);

      if (!buf)

  {

    GDBM_SET_ERRNO (dbf, GDBM_MALLOC_ERROR, FALSE);

    return -1;

  }

      /* Invalidate file_size */

      dbf->file_size = -1;

      while (size)

  {

    ssize_t n = write (dbf->desc, buf,

           size < page_size ? size : page_size);

    if (n <= 0)

      {

        GDBM_SET_ERRNO (dbf, GDBM_FILE_WRITE_ERROR, TRUE);

        break;

      }

    size -= n;

  }

      free (buf);

      if (size)

  return -1;

    }

  return 0;

}