/*

 * Byte stream functions

 *

 * Copyright (C) 2011-2024, 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 "libevtx_byte_stream.h"

#include "libevtx_libcerror.h"

#include "libevtx_types.h"

/* Checks if a byte stream is filled with 0-byte values

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

 */

int libevtx_byte_stream_check_for_zero_byte_fill(

     const uint8_t *byte_stream,

     size_t byte_stream_size,

     libcerror_error_t **error )

{

  libevtx_aligned_t *aligned_byte_stream_index = NULL;

  uint8_t *byte_stream_index                   = NULL;

  static char *function                        = "libevtx_byte_stream_check_for_zero_byte_fill";

  if( byte_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid byte stream.",

     function );

    return( -1 );

  }

  if( byte_stream_size > (size_t) SSIZE_MAX )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_EXCEEDS_MAXIMUM,

     "%s: invalid byte stream size value exceeds maximum.",

     function );

    return( -1 );

  }

  byte_stream_index = (uint8_t *) byte_stream;

  /* Only optimize for byte stream larger than the alignment

   */

  if( byte_stream_size > ( 2 * sizeof( libevtx_aligned_t ) ) )

  {

    /* Align the byte stream index

     */

    while( ( (intptr_t) byte_stream_index % sizeof( libevtx_aligned_t ) ) != 0 )

    {

      if( *byte_stream_index != 0 )

      {

        return( 0 );

      }

      byte_stream_index += 1;

      byte_stream_size  -= 1;

    }

    aligned_byte_stream_index = (libevtx_aligned_t *) byte_stream_index;

    while( byte_stream_size > sizeof( libevtx_aligned_t ) )

    {

      if( *aligned_byte_stream_index != 0 )

      {

        return( 0 );

      }

      aligned_byte_stream_index += 1;

      byte_stream_size          -= sizeof( libevtx_aligned_t );

    }

    byte_stream_index = (uint8_t *) aligned_byte_stream_index;

  }

  while( byte_stream_size != 0 )

  {

    if( *byte_stream_index != 0 )

    {

      return( 0 );

    }

    byte_stream_index += 1;

    byte_stream_size  -= 1;

  }

  return( 1 );

}