segment/format.c File Reference

#include <grass/config.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <limits.h>
#include <grass/segment.h>

Include dependency graph for segment/format.c:

Go to the source code of this file.

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

Function Documentation

int segment_format	(	int	fd,
		int	nrows,
		int	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 62 of file segment/format.c.

Referenced by main().

int segment_format_nofill	(	int	fd,
		int	nrows,
		int	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).

Note: This version of the function does not fill in the initialized data structures with zeros.

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 102 of file segment/format.c.