Segment formatting routines. More...

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <limits.h>
#include <grass/gis.h>
#include <grass/glocale.h>
#include "local_proto.h"

Include dependency graph for segment/format.c:

Go to the source code of this file.

Functions
int	Segment_format (int fd, off_t nrows, off_t ncols, int srows, int scols, int len)
	Format a segment file. More...

int	Segment_format_nofill (int fd, off_t nrows, off_t ncols, int srows, int scols, int len)
	Format a segment file. More...

Detailed Description

Segment formatting routines.

This program is free software under the GNU General Public License (>=v2). Read the file COPYING that comes with GRASS for details.

Author: GRASS GIS Development Team

Date: 2005-2018

Definition in file segment/format.c.

Function Documentation

◆ Segment_format()

int Segment_format	(	int	fd,
		off_t	nrows,
		off_t	ncols,
		int	srows,
		int	scols,
		int	len
	)

Format a segment file.

The segmentation routines require a disk file to be used for paging segments in and out of memory. This routine formats the file open for write on file descriptor fd for use as a segment file.

A segment file must be formatted before it can be processed by other segment routines. The configuration parameters nrows, ncols, srows, scols, and len are written to the beginning of the segment file which is then filled with zeros.

The corresponding nonsegmented data matrix, which is to be transferred to the segment file, is nrows by ncols. The segment file is to be formed of segments which are srows by scols. The data items have length len bytes. For example, if the data type is int, len is sizeof(int).

Parameters

[in]	fd	file descriptor
[in]	nrows	number of non-segmented rows
[in]	ncols	number of non-segmented columns
[in]	srows	segment rows
[in]	scols	segment columns
[in]	len	length of data type

Returns: 1 of successful; -1 if unable to seek or write fd; -3 if illegal parameters are passed

Definition at line 63 of file segment/format.c.

◆ Segment_format_nofill()

int Segment_format_nofill	(	int	fd,
		off_t	nrows,
		off_t	ncols,
		int	srows,
		int	scols,
		int	len
	)