/*

 * Data 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 "libfshfs_allocation_block_stream.h"

#include "libfshfs_data_stream.h"

#include "libfshfs_definitions.h"

#include "libfshfs_extent.h"

#include "libfshfs_file_system.h"

#include "libfshfs_fork_descriptor.h"

#include "libfshfs_io_handle.h"

#include "libfshfs_libbfio.h"

#include "libfshfs_libcdata.h"

#include "libfshfs_libcerror.h"

#include "libfshfs_libcthreads.h"

#include "libfshfs_libfdata.h"

#include "libfshfs_types.h"

/* Creates a data stream

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

 * Returns 1 if successful or -1 on error

 */

int libfshfs_data_stream_initialize(

     libfshfs_data_stream_t **data_stream,

     libfshfs_io_handle_t *io_handle,

     libbfio_handle_t *file_io_handle,

     libfshfs_file_system_t *file_system,

     uint32_t identifier,

     libfshfs_fork_descriptor_t *fork_descriptor,

     uint8_t fork_type,

     libcerror_error_t **error )

{

  libfshfs_internal_data_stream_t *internal_data_stream = NULL;

  static char *function                                 = "libfshfs_data_stream_initialize";

  if( data_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data stream.",

     function );

    return( -1 );

  }

  if( *data_stream != NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_VALUE_ALREADY_SET,

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

     function );

    return( -1 );

  }

  if( ( fork_type != LIBFSHFS_FORK_TYPE_DATA )

   && ( fork_type != LIBFSHFS_FORK_TYPE_RESOURCE ) )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_UNSUPPORTED_VALUE,

     "%s: unsupported fork type.",

     function );

    return( -1 );

  }

  internal_data_stream = memory_allocate_structure(

                          libfshfs_internal_data_stream_t );

  if( internal_data_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_INITIALIZE_FAILED,

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

     function );

    goto on_error;

  }

  if( memory_set(

       internal_data_stream,

       0,

       sizeof( libfshfs_internal_data_stream_t ) ) == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_MEMORY,

     LIBCERROR_MEMORY_ERROR_SET_FAILED,

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

     function );

    memory_free(

     internal_data_stream );

    return( -1 );

  }

  if( libfshfs_file_system_get_extents(

       file_system,

       file_io_handle,

       identifier,

       fork_type,

       fork_descriptor,

       &( internal_data_stream->extents_array ),

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_GET_FAILED,

     "%s: unable to retrieve extents of data stream.",

     function );

    goto on_error;

  }

  if( libfshfs_allocation_block_stream_initialize_from_extents(

       &( internal_data_stream->allocation_block_stream ),

       io_handle,

       internal_data_stream->extents_array,

       (size64_t) fork_descriptor->size,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_INITIALIZE_FAILED,

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

     function );

    goto on_error;

  }

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_initialize(

       &( internal_data_stream->read_write_lock ),

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_INITIALIZE_FAILED,

     "%s: unable to initialize read/write lock.",

     function );

    goto on_error;

  }

#endif

  internal_data_stream->io_handle      = io_handle;

  internal_data_stream->file_io_handle = file_io_handle;

  *data_stream = (libfshfs_data_stream_t *) internal_data_stream;

  return( 1 );

on_error:

  if( internal_data_stream != NULL )

  {

    if( internal_data_stream->allocation_block_stream != NULL )

    {

      libfdata_stream_free(

       &( internal_data_stream->allocation_block_stream ),

       NULL );

    }

    if( internal_data_stream->extents_array != NULL )

    {

      libcdata_array_free(

       &( internal_data_stream->extents_array ),

       (int (*)(intptr_t **, libcerror_error_t **)) &libfshfs_extent_free,

       NULL );

    }

    memory_free(

     internal_data_stream );

  }

  return( -1 );

}

/* Frees a data stream

 * Returns 1 if successful or -1 on error

 */

int libfshfs_data_stream_free(

     libfshfs_data_stream_t **data_stream,

     libcerror_error_t **error )

{

  libfshfs_internal_data_stream_t *internal_data_stream = NULL;

  static char *function                                 = "libfshfs_data_stream_free";

  int result                                            = 1;

  if( data_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data stream.",

     function );

    return( -1 );

  }

  if( *data_stream != NULL )

  {

    internal_data_stream = (libfshfs_internal_data_stream_t *) *data_stream;

    *data_stream         = NULL;

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

    if( libcthreads_read_write_lock_free(

         &( internal_data_stream->read_write_lock ),

         error ) != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_RUNTIME,

       LIBCERROR_RUNTIME_ERROR_FINALIZE_FAILED,

       "%s: unable to free read/write lock.",

       function );

      result = -1;

    }

#endif

    /* The file_io_handle reference is freed elsewhere

     */

    if( libfdata_stream_free(

         &( internal_data_stream->allocation_block_stream ),

         error ) != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_RUNTIME,

       LIBCERROR_RUNTIME_ERROR_FINALIZE_FAILED,

       "%s: unable to free allocation block stream.",

       function );

      result = -1;

    }

    if( libcdata_array_free(

         &( internal_data_stream->extents_array ),

         (int (*)(intptr_t **, libcerror_error_t **)) &libfshfs_extent_free,

         error ) != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_RUNTIME,

       LIBCERROR_RUNTIME_ERROR_FINALIZE_FAILED,

       "%s: unable to free extents array.",

       function );

      result = -1;

    }

    memory_free(

     internal_data_stream );

  }

  return( result );

}

/* Reads data at the current offset

 * Returns the number of bytes read or -1 on error

 */

ssize_t libfshfs_data_stream_read_buffer(

         libfshfs_data_stream_t *data_stream,

         void *buffer,

         size_t buffer_size,

         libcerror_error_t **error )

{

  libfshfs_internal_data_stream_t *internal_data_stream = NULL;

  static char *function                                 = "libfshfs_data_stream_read_buffer";

  ssize_t read_count                                    = 0;

  if( data_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data stream.",

     function );

    return( -1 );

  }

  internal_data_stream = (libfshfs_internal_data_stream_t *) data_stream;

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_grab_for_write(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to grab read/write lock for writing.",

     function );

    return( -1 );

  }

#endif

  read_count = libfdata_stream_read_buffer(

                internal_data_stream->allocation_block_stream,

                (intptr_t *) internal_data_stream->file_io_handle,

                buffer,

                buffer_size,

                0,

                error );

  if( read_count < 0 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_IO,

     LIBCERROR_IO_ERROR_READ_FAILED,

     "%s: unable to read from allocation block stream.",

     function );

    read_count = -1;

  }

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_release_for_write(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to release read/write lock for writing.",

     function );

    return( -1 );

  }

#endif

  return( read_count );

}

/* Reads data at a specific offset

 * Returns the number of bytes read or -1 on error

 */

ssize_t libfshfs_data_stream_read_buffer_at_offset(

         libfshfs_data_stream_t *data_stream,

         void *buffer,

         size_t buffer_size,

         off64_t offset,

         libcerror_error_t **error )

{

  libfshfs_internal_data_stream_t *internal_data_stream = NULL;

  static char *function                                 = "libfshfs_data_stream_read_buffer_at_offset";

  ssize_t read_count                                    = 0;

  if( data_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data stream.",

     function );

    return( -1 );

  }

  internal_data_stream = (libfshfs_internal_data_stream_t *) data_stream;

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_grab_for_write(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to grab read/write lock for writing.",

     function );

    return( -1 );

  }

#endif

  read_count = libfdata_stream_read_buffer_at_offset(

                internal_data_stream->allocation_block_stream,

                (intptr_t *) internal_data_stream->file_io_handle,

                buffer,

                buffer_size,

                offset,

                0,

                error );

  if( read_count < 0 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_IO,

     LIBCERROR_IO_ERROR_READ_FAILED,

     "%s: unable to read from allocation block stream.",

     function );

    read_count = -1;

  }

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_release_for_write(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to release read/write lock for writing.",

     function );

    return( -1 );

  }

#endif

  return( read_count );

}

/* Seeks a certain offset

 * Returns the offset if seek is successful or -1 on error

 */

off64_t libfshfs_data_stream_seek_offset(

         libfshfs_data_stream_t *data_stream,

         off64_t offset,

         int whence,

         libcerror_error_t **error )

{

  libfshfs_internal_data_stream_t *internal_data_stream = NULL;

  static char *function                                 = "libfshfs_data_stream_seek_offset";

  if( data_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data stream.",

     function );

    return( -1 );

  }

  internal_data_stream = (libfshfs_internal_data_stream_t *) data_stream;

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_grab_for_write(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to grab read/write lock for writing.",

     function );

    return( -1 );

  }

#endif

  offset = libfdata_stream_seek_offset(

            internal_data_stream->allocation_block_stream,

            offset,

            whence,

            error );

  if( offset == -1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_IO,

     LIBCERROR_IO_ERROR_SEEK_FAILED,

     "%s: unable to seek offset in allocation block stream.",

     function );

    offset = -1;

  }

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_release_for_write(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to release read/write lock for writing.",

     function );

    return( -1 );

  }

#endif

  return( offset );

}

/* Retrieves the current offset

 * Returns the offset if successful or -1 on error

 */

int libfshfs_data_stream_get_offset(

     libfshfs_data_stream_t *data_stream,

     off64_t *offset,

     libcerror_error_t **error )

{

  libfshfs_internal_data_stream_t *internal_data_stream = NULL;

  static char *function                                 = "libfshfs_data_stream_get_offset";

  int result                                            = 1;

  if( data_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data stream.",

     function );

    return( -1 );

  }

  internal_data_stream = (libfshfs_internal_data_stream_t *) data_stream;

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_grab_for_read(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to grab read/write lock for reading.",

     function );

    return( -1 );

  }

#endif

  if( libfdata_stream_get_offset(

       internal_data_stream->allocation_block_stream,

       offset,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_GET_FAILED,

     "%s: unable to retrieve offset from allocation block stream.",

     function );

    result = -1;

  }

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_release_for_read(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to release read/write lock for reading.",

     function );

    return( -1 );

  }

#endif

  return( result );

}

/* Retrieves the size

 * Returns 1 if successful or -1 on error

 */

int libfshfs_data_stream_get_size(

     libfshfs_data_stream_t *data_stream,

     size64_t *size,

     libcerror_error_t **error )

{

  libfshfs_internal_data_stream_t *internal_data_stream = NULL;

  static char *function                                 = "libfshfs_data_stream_get_size";

  int result                                            = 1;

  if( data_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data stream.",

     function );

    return( -1 );

  }

  internal_data_stream = (libfshfs_internal_data_stream_t *) data_stream;

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_grab_for_read(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to grab read/write lock for reading.",

     function );

    return( -1 );

  }

#endif

  if( libfdata_stream_get_size(

       internal_data_stream->allocation_block_stream,

       size,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_GET_FAILED,

     "%s: unable to retrieve size from allocation block stream.",

     function );

    result = -1;

  }

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_release_for_read(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to release read/write lock for reading.",

     function );

    return( -1 );

  }

#endif

  return( result );

}

/* Retrieves the number of extents (decoded data runs)

 * Returns 1 if successful or -1 on error

 */

int libfshfs_data_stream_get_number_of_extents(

     libfshfs_data_stream_t *data_stream,

     int *number_of_extents,

     libcerror_error_t **error )

{

  libfshfs_internal_data_stream_t *internal_data_stream = NULL;

  static char *function                                 = "libfshfs_data_stream_get_number_of_extents";

  int result                                            = 1;

  if( data_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data stream.",

     function );

    return( -1 );

  }

  internal_data_stream = (libfshfs_internal_data_stream_t *) data_stream;

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_grab_for_read(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to grab read/write lock for reading.",

     function );

    return( -1 );

  }

#endif

  if( libcdata_array_get_number_of_entries(

       internal_data_stream->extents_array,

       number_of_extents,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_GET_FAILED,

     "%s: unable to retrieve number of extents.",

     function );

    result = -1;

  }

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_release_for_read(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to release read/write lock for reading.",

     function );

    return( -1 );

  }

#endif

  return( result );

}

/* Retrieves a specific extent (decoded data run)

 * Returns 1 if successful or -1 on error

 */

int libfshfs_data_stream_get_extent_by_index(

     libfshfs_data_stream_t *data_stream,

     int extent_index,

     off64_t *extent_offset,

     size64_t *extent_size,

     uint32_t *extent_flags,

     libcerror_error_t **error )

{

  libfshfs_extent_t *data_extent                        = NULL;

  libfshfs_internal_data_stream_t *internal_data_stream = NULL;

  static char *function                                 = "libfshfs_data_stream_get_extent_by_index";

  int result                                            = 1;

  if( data_stream == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data stream.",

     function );

    return( -1 );

  }

  internal_data_stream = (libfshfs_internal_data_stream_t *) data_stream;

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_grab_for_read(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to grab read/write lock for reading.",

     function );

    return( -1 );

  }

#endif

  if( libcdata_array_get_entry_by_index(

       internal_data_stream->extents_array,

       extent_index,

       (intptr_t **) &data_extent,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_GET_FAILED,

     "%s: unable to retrieve extent: %d.",

     function,

     extent_index );

    result = -1;

  }

  if( result == 1 )

  {

    if( libfshfs_extent_get_values(

         data_extent,

         internal_data_stream->io_handle,

         extent_offset,

         extent_size,

         extent_flags,

         error ) != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_RUNTIME,

       LIBCERROR_RUNTIME_ERROR_GET_FAILED,

       "%s: unable to retrieve extent: %d values.",

       function,

       extent_index );

      result = -1;

    }

  }

#if defined( HAVE_LIBFSHFS_MULTI_THREAD_SUPPORT )

  if( libcthreads_read_write_lock_release_for_read(

       internal_data_stream->read_write_lock,

       error ) != 1 )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_SET_FAILED,

     "%s: unable to release read/write lock for reading.",

     function );

    return( -1 );

  }

#endif

  return( result );

}