/*

 * Block functions

 *

 * Copyright (C) 2010-2026, Joachim Metz <joachim.metz@gmail.com>

 *

 * Refer to AUTHORS for acknowledgements.

 *

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

 * it under the terms of the GNU Lesser 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 Lesser General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>.

 */

#include <common.h>

#include <types.h>

#include "libfsext_libcerror.h"

#include "libfsext_types.h"

/* Checks if a buffer block data is filled with 0-byte values (empty-block)

 * Returns 1 if empty, 0 if not or -1 on error

 */

int libfsext_block_data_check_empty(

     const uint8_t *data,

     size_t data_size,

     libcerror_error_t **error )

{

  libfsext_aligned_t *aligned_data_index = NULL;

  libfsext_aligned_t *aligned_data_start = NULL;

  uint8_t *data_index                    = NULL;

  uint8_t *data_start                    = NULL;

  static char *function                  = "libfsext_block_data_check_empty";

  if( data == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data.",

     function );

    return( -1 );

  }

  if( data_size > (size_t) SSIZE_MAX )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_EXCEEDS_MAXIMUM,

     "%s: invalid data size value exceeds maximum.",

     function );

    return( -1 );

  }

  data_start = (uint8_t *) data;

  data_index = (uint8_t *) data + 1;

  data_size -= 1;

  /* Only optimize for data larger than the alignment

   */

  if( data_size > ( 2 * sizeof( libfsext_aligned_t ) ) )

  {

    /* Align the data start

     */

    while( ( (intptr_t) data_start % sizeof( libfsext_aligned_t ) ) != 0 )

    {

      if( *data_start != *data_index )

      {

        return( 0 );

      }

      data_start += 1;

      data_index += 1;

      data_size  -= 1;

    }

    /* Align the data index

     */

    while( ( (intptr_t) data_index % sizeof( libfsext_aligned_t ) ) != 0 )

    {

      if( *data_start != *data_index )

      {

        return( 0 );

      }

      data_index += 1;

      data_size  -= 1;

    }

    aligned_data_start = (libfsext_aligned_t *) data_start;

    aligned_data_index = (libfsext_aligned_t *) data_index;

    while( data_size > sizeof( libfsext_aligned_t ) )

    {

      if( *aligned_data_start != *aligned_data_index )

      {

        return( 0 );

      }

      aligned_data_index += 1;

      data_size          -= sizeof( libfsext_aligned_t );

    }

    data_index = (uint8_t *) aligned_data_index;

  }

  while( data_size != 0 )

  {

    if( *data_start != *data_index )

    {

      return( 0 );

    }

    data_index += 1;

    data_size  -= 1;

  }

  return( 1 );

}