/*

 * Bit-stream functions

 *

 * Copyright (C) 2009-2024, 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 <memory.h>

#include <types.h>

#include "libfwnt_bit_stream.h"

#include "libfwnt_libcerror.h"

/* Creates a bit stream

 * Make sure the value bit_stream is referencing, is set to NULL

 * Returns 1 if successful or -1 on error

 */

int libfwnt_bit_stream_initialize(

     libfwnt_bit_stream_t **bit_stream,

     const uint8_t *byte_stream,

     size_t byte_stream_size,

     libcerror_error_t **error )

{

  static char *function = "libfwnt_bit_stream_initialize";

  if( bit_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid bit stream.",

     function );

    return( -1 );

  }

  if( *bit_stream != NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_VALUE_ALREADY_SET,

     "%s: invalid bit stream value already set.",

     function );

    return( -1 );

  }

  if( byte_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid byte stream value.",

     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: byte stream size value exceeds maximum.",

     function );

    return( -1 );

  }

  *bit_stream = memory_allocate_structure(

                 libfwnt_bit_stream_t );

  if( *bit_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_MEMORY,

     LIBCERROR_MEMORY_ERROR_INSUFFICIENT,

     "%s: unable to create bit stream.",

     function );

    goto on_error;

  }

  if( memory_set(

       *bit_stream,

       0,

       sizeof( libfwnt_bit_stream_t ) ) == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_MEMORY,

     LIBCERROR_MEMORY_ERROR_SET_FAILED,

     "%s: unable to clear bit stream.",

     function );

    goto on_error;

  }

  ( *bit_stream )->byte_stream      = byte_stream;

  ( *bit_stream )->byte_stream_size = byte_stream_size;

  return( 1 );

on_error:

  if( *bit_stream != NULL )

  {

    memory_free(

     *bit_stream );

    *bit_stream = NULL;

  }

  return( -1 );

}

/* Frees a bit stream

 * Returns 1 if successful or -1 on error

 */

int libfwnt_bit_stream_free(

     libfwnt_bit_stream_t **bit_stream,

     libcerror_error_t **error )

{

  static char *function = "libfwnt_bit_stream_free";

  if( bit_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid bit stream.",

     function );

    return( -1 );

  }

  if( *bit_stream != NULL )

  {

    memory_free(

     *bit_stream );

    *bit_stream = NULL;

  }

  return( 1 );

}

/* Reads bits from the underlying byte stream

 * Returns 1 on success or -1 on error

 */

int libfwnt_bit_stream_read(

     libfwnt_bit_stream_t *bit_stream,

     uint8_t number_of_bits,

     libcerror_error_t **error )

{

  static char *function = "libfwnt_bit_stream_read";

  if( bit_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid bit stream.",

     function );

    return( -1 );

  }

  if( ( number_of_bits == 0 )

   || ( number_of_bits > 32 ) )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_OUT_OF_BOUNDS,

     "%s: number of bits value out of bounds.",

     function );

    return( -1 );

  }

  while( bit_stream->bit_buffer_size < number_of_bits )

  {

    if( ( bit_stream->byte_stream_size < 2 )

     || ( bit_stream->byte_stream_offset > ( bit_stream->byte_stream_size - 2 ) ) )

    {

      /* If the bit stream overflows fill the bit buffer with 0 byte values

       */

      bit_stream->bit_buffer     <<= 16;

      bit_stream->bit_buffer_size += 16;

    }

    else

    {

      bit_stream->bit_buffer     <<= 8;

      bit_stream->bit_buffer      |= bit_stream->byte_stream[ bit_stream->byte_stream_offset + 1 ];

      bit_stream->bit_buffer     <<= 8;

      bit_stream->bit_buffer      |= bit_stream->byte_stream[ bit_stream->byte_stream_offset ];

      bit_stream->bit_buffer_size += 16;

      bit_stream->byte_stream_offset += 2;

    }

  }

  return( 1 );

}

/* Retrieves a value from the bit stream

 * Returns 1 on success or -1 on error

 */

int libfwnt_bit_stream_get_value(

     libfwnt_bit_stream_t *bit_stream,

     uint8_t number_of_bits,

     uint32_t *value_32bit,

     libcerror_error_t **error )

{

  static char *function             = "libfwnt_bit_stream_get_value";

  uint32_t safe_value_32bit         = 0;

  uint8_t remaining_bit_buffer_size = 0;

  if( bit_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid bit stream.",

     function );

    return( -1 );

  }

  if( number_of_bits > (uint8_t) 32 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_EXCEEDS_MAXIMUM,

     "%s: invalid number of bits value exceeds maximum.",

     function );

    return( -1 );

  }

  if( value_32bit == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid 32-bit value.",

     function );

    return( -1 );

  }

  if( number_of_bits == 0 )

  {

    *value_32bit = 0;

    return( 1 );

  }

  if( bit_stream->bit_buffer_size < number_of_bits )

  {

    if( libfwnt_bit_stream_read(

         bit_stream,

         number_of_bits,

         error ) != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_IO,

       LIBCERROR_IO_ERROR_READ_FAILED,

       "%s: unable to read bits.",

       function );

      return( -1 );

    }

  }

  safe_value_32bit = bit_stream->bit_buffer;

  if( number_of_bits < 32 )

  {

    safe_value_32bit >>= bit_stream->bit_buffer_size - number_of_bits;

  }

  bit_stream->bit_buffer_size -= number_of_bits;

  /* The behavior of "bit_buffer & ( 0xfffffffUL >> 32 )" differs for some compilers.

   */

  if( bit_stream->bit_buffer_size == 0 )

  {

    bit_stream->bit_buffer = 0;

  }

  else

  {

    remaining_bit_buffer_size = 32 - bit_stream->bit_buffer_size;

    bit_stream->bit_buffer   &= 0xffffffffUL >> remaining_bit_buffer_size;

  }

  *value_32bit = safe_value_32bit;

  return( 1 );

}