cell_stats.c File Reference

#include <grass/gis.h>
#include <stdlib.h>

Include dependency graph for cell_stats.c:

Go to the source code of this file.

Macros
#define	INCR   10
#define	SHIFT   6
#define	NODE   struct Cell_stats_node

Functions
int	G_init_cell_stats (struct Cell_stats *s)
	initialize cell stats More...
int	G_update_cell_stats (const CELL *cell, int n, struct Cell_stats *s)
	add data to cell stats More...
int	G_find_cell_stat (CELL cat, long *count, const struct Cell_stats *s)
	random query of cell stats More...
int	G_rewind_cell_stats (struct Cell_stats *s)
	reset/rewind cell stats More...
int	G_next_cell_stat (CELL *cat, long *count, struct Cell_stats *s)
	retrieve sorted cell stats More...
int	G_get_stats_for_null_value (long *count, const struct Cell_stats *s)
	Get a number of null values from stats structure. Note: when reporting values which appear in a map using G_next_cell_stats(), to get stats for null, call G_get_stats_for_null_value() first, since G_next_cell_stats() does not report stats for null. More...
int	G_free_cell_stats (struct Cell_stats *s)
	free cell stats More...

Macro Definition Documentation

#define INCR   10

Definition at line 4 of file cell_stats.c.

Referenced by G_init_cell_stats(), and G_update_cell_stats().

#define NODE   struct Cell_stats_node

Definition at line 9 of file cell_stats.c.

Referenced by G_init_cell_stats(), and G_update_cell_stats().

#define SHIFT   6

Definition at line 5 of file cell_stats.c.

Referenced by G_find_cell_stat(), G_next_cell_stat(), and G_update_cell_stats().

Function Documentation

int G_find_cell_stat	(	CELL	cat,
		long *	count,
		const struct Cell_stats *	s
	)

random query of cell stats

This routine allows a random query of the Cell_stats structure s. The count associated with the raster value cat is set. The routine returns 1 if cat was found in the structure, 0 otherwise.

Parameters

cat
count
s

Returns

int

Allow finding the count for the NULL-value

Returns

int

Definition at line 204 of file cell_stats.c.

References cat, G_is_c_null_value(), forms::q, and SHIFT.

int G_free_cell_stats

(

struct Cell_stats *

s

)

free cell stats

The memory associated with structure s is freed. This routine may be called any time after callingG_init_cell_stats.

Parameters

s

Returns

int

Definition at line 413 of file cell_stats.c.

References G_free().

int G_get_stats_for_null_value	(	long *	count,
		const struct Cell_stats *	s
	)

Get a number of null values from stats structure. Note: when reporting values which appear in a map using G_next_cell_stats(), to get stats for null, call G_get_stats_for_null_value() first, since G_next_cell_stats() does not report stats for null.

Parameters

count
s

Returns

int

Definition at line 396 of file cell_stats.c.

int G_init_cell_stats

(

struct Cell_stats *

s

)

initialize cell stats

This routine, which must be called first, initializes the Cell_stats structure s.

Parameters

s

Returns

int

Set the count for NULL-values to zero.

Returns

int

Definition at line 34 of file cell_stats.c.

References INCR, and NODE.

int G_next_cell_stat	(	CELL *	cat,
		long *	count,
		struct Cell_stats *	s
	)

retrieve sorted cell stats

Retrieves the next cat,count combination from the structure s. Returns 0 if there are no more items, non-zero if there are more. For example:

struct Cell_stats s;
CELL cat;
long count;

// updating <b>s</b> occurs here

G_rewind_cell_stats(&s);
while (G_next_cell_stat(&cat,&count,&s)
fprintf(stdout, "%ld %ld\n", (long) cat, count);

Parameters

cat
count
s

Returns

int

Do not return a record for the NULL-value

Returns

int

Definition at line 338 of file cell_stats.c.

References SHIFT.

Referenced by G_cell_stats_histo_eq(), G_histogram_eq_colors(), G_make_histogram_cs(), G_make_histogram_eq_colors(), G_make_histogram_log_colors(), and G_write_histogram_cs().

int G_rewind_cell_stats

(

struct Cell_stats *

s

)

reset/rewind cell stats

The structure s is rewound (i.e., positioned at the first raster category) so that sorted sequential retrieval can begin.

Parameters

s

Returns

int

Definition at line 265 of file cell_stats.c.

References forms::q.

Referenced by G_cell_stats_histo_eq(), G_histogram_eq_colors(), G_make_histogram_cs(), G_make_histogram_eq_colors(), G_make_histogram_log_colors(), and G_write_histogram_cs().

int G_update_cell_stats	(	const CELL *	cell,
		int	n,
		struct Cell_stats *	s
	)

add data to cell stats

The n CELL values in the data array are inserted (and counted) in the Cell_stats structure s.

Parameters

data
n
s

Returns

int

Look for NULLs and update the NULL-value count.

Returns

int

Definition at line 67 of file cell_stats.c.

References cat, G_is_c_null_value(), INCR, N, NODE, forms::q, and SHIFT.

Referenced by G_put_map_row_random().