/*----------------------------------------------------------------------*\
 | Functions to return, given the name of any sensor, its offset in the	|
 | dwd structure; given a list of such names, to return a list of the	|
 | corresponding offsets; and, given an offset into the structure, to	|
 | return the name of the sensor.										|
 |																		|
 | Peter N. Schweitzer (U.S. Geological Survey, Reston, VA 22092)		|
\*----------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "dw.h"

static char msg [1024];

#define offsetof(p_type,field) ((int)&(((p_type)NULL)->field))

struct offset_table {
	int offset;
	char *name;
	};

static struct offset_table dwd_table [] = {
	{offsetof (struct dwd *,hum),	"humidity"},
	{offsetof (struct dwd *,ppt),	"precipitation"},
	{offsetof (struct dwd *,bp),	"barometric pressure"},
	{offsetof (struct dwd *,wd),	"wind direction"},
	{offsetof (struct dwd *,ws20),	"wind speed at 6.1m"},
	{offsetof (struct dwd *,pg20),	"peak gust at 6.1m"},
	{offsetof (struct dwd *,ws88),	"wind speed at 2.7m"},
	{offsetof (struct dwd *,ws4),	"wind speed at 1.2m"},
	{offsetof (struct dwd *,pg4),	"peak gust at 1.2m"},
	{offsetof (struct dwd *,at20),	"air temperature at 6.1m"},
	{offsetof (struct dwd *,at4),	"air temperature at 1.2m"},
	{offsetof (struct dwd *,st4),	"soil temperature at  4cm"},
	{offsetof (struct dwd *,st10),	"soil temperature at 10cm"},
	{offsetof (struct dwd *,st20),	"soil temperature at 20cm"},
	{offsetof (struct dwd *,srsi),	"solar radiation (short, in)"},
	{offsetof (struct dwd *,srli),	"solar radiation (long, in)"},
	{offsetof (struct dwd *,srso),	"solar radiation (short, out)"},
	{offsetof (struct dwd *,srlo),	"solar radiation (long, out)"},
	{offsetof (struct dwd *,sb),	"shadow band"},
	{offsetof (struct dwd *,bt1),	"brightness temperature, band 1"},
	{offsetof (struct dwd *,bt2),	"brightness temperature, band 2"},
	{offsetof (struct dwd *,bt3),	"brightness temperature, band 3"},
	{offsetof (struct dwd *,bt4),	"brightness temperature, band 4"},
	{-1,							NULL}
	};

int get_variable_offset (char *sensor_name) {
	int j;
	for (j=0; dwd_table[j].name; j++)
		if (strcmp (sensor_name,dwd_table[j].name) == 0)
			return (dwd_table[j].offset);
	return (-1);
	}

int *get_offset_list (char **selected_sensor, int number_selected) {
	int i,j;
	int *offset_list,*L;

	if (offset_list = (int *) malloc ((1 + number_selected)*sizeof(int))) {
		L = offset_list;
		for (i=0; i < number_selected; i++)  {
			j = get_variable_offset (selected_sensor[i]);
			if (j == -1) {
				sprintf (msg,"Warning: unrecognized sensor name: \"%s\"",selected_sensor[i]);
				dw_warn (msg);
				}
			else *L++ = j;
			}
		}
	*L = -1;

	/*------------------------------------------------------------------*\
	 | If any sensor names were recognized, return the array.  If none	|
	 | were recognized, free the array and return NULL.					|
	\*------------------------------------------------------------------*/

	if (L == offset_list) {
		free (offset_list);
		offset_list = NULL;
		}
	return (offset_list);
	}

char *get_variable_name (int offset) {
	int j;
	for (j=0; dwd_table[j].offset != -1; j++)
		if (offset == dwd_table[j].offset)
			return (dwd_table[j].name);
	return (NULL);
	}

/*----------------------------------------------------------------------*\
\*----------------------------------------------------------------------*/