/***********************************************************************

NAME:		V_const()

FUNCTION:	Allows a program to identify a constant, and where that
			constant should be placed on the screen in the next call
			to V_call()

USAGE:		V_const(targetptr, var_type, row, col, length) 

PARAMETERS:          union target targetptr ;
			int   var_type         ;     'i', 'l', 'f', 'd', or 's'
			int   row              ;     0 <= row <= MAX_LINE
			int   col              ;     0 <= col <= 80
			int   length           ;     0 <= length <= 80

RETURNS:	zero (0) on success and negative 1 (-1) on failure

ALGORITHM:	
		|	Check to see if request is legal and on the screen
		|		If not, return -1
		|	Make assignments
		|	return 0

CALLS:		
		none

***********************************************************************/

#include <grass/vask.h>

/*!
 * \brief define screen constant
 *
 * <i>Ctype</i> is one of int, long, float,
 * double, or char.
 *
 *  \param value
 *  \param type
 *  \param row
 *  \param col
 *  \param len
 *  \return int
 */

int V_const(
    void  *src   ,
    char  var_type ,
    int   row      ,
    int   col      ,
    int   length   )
{
    union target targetptr ;
    targetptr.i = src;

    if (V__.NUM_CONST >= MAX_CONST ) 
    {
	V_error("Too many constants in call to V_const") ;
	return(-1) ;
    }
    if ((row < 0) || (row >= MAX_LINE))
    {
	char msg[80];
	sprintf (msg,"Illegal row (%d) in call to V_const", row);
	V_error(msg) ;
	return(-1) ;
    }
    if ((col < 0) || (col > 80))
    {
	char msg[80];
	sprintf (msg,"Illegal column (%d) in call to V_const", col);
	V_error(msg) ;
	return(-1) ;
    }
    if ((length < 0) || ((length + col) > 80))
    {
	V_error("Length out of bounds in call to V_const") ;
	return(-1) ;
    }

    if ((var_type == 's') || (var_type == 'i') || (var_type == 'f')
    ||  (var_type == 'l') || (var_type == 'd'))
    {
	V__.constant[V__.NUM_CONST].targetptr = targetptr ;
	V__.constant[V__.NUM_CONST].var_type  = var_type  ;
	V__.constant[V__.NUM_CONST].row       = row       ;
	V__.constant[V__.NUM_CONST].col       = col       ;
	V__.constant[V__.NUM_CONST].length    = length    ;
	V__.constant[V__.NUM_CONST].decimal_places    = V__.decimal_places    ;

	V__.NUM_CONST++ ;
	return(0) ;
    }
    else
    {
	V_error("Illegal variable type in call to V_const") ;
	return(-1) ;
    }
}