#		This just parses a few of the canonical fields
#		John Leibacher: 21 November, 1999
{
package TX ;
#
#-------- Read a World Wide Soaring Turnpoint Exchange File --------------------
#
#	returned to the main:	
#		the definitions of the columns in the hash "col"
#		the file definitions in the hash "file_definitions"
#		the waypoint data in the array "cells"
#
#		"altitude_unit", if defined
#
#	if  $TX::quiet is defined, messages turned off [ not recommended!! ]
#	if  $TX::debug is defined, debugging messages turned on
#
local ( $filename ) ;
#
#-------------------------------------------------------------------------------
sub read {
#
local ( $line ) ;
local ( $return_value ) ;
REREAD:
	if( $_ = <IN> ) { 
		s/\cM//g ;
		chop ;
		$line .= $_ ;
#				Note, concatenation performed before comments are stripped,
#					so multiple line comments are allowed
		if( $line =~ s/\\\s*$// ) { goto REREAD ; }	#	Concatanate lines
#
#			Strip comment	
		$line =~ s/\s*\*.*$// ;
#			Skip blank line
		if( $line =~ /^\s*$/ ) { undef $line ; goto REREAD ; }
#
		if( $line =~ s/^\s*\$\s*// ) {
			&file_definitions ;
			$return_value = 2 ;
		}
		elsif( ! defined $column_definitions_read ) {
			$column_definitions_read = 'y' ;
			&column_definitions ;
			$return_value = 1 ;
		}
		else {
			if( $sep eq '\,' ) {
				local ( $commas_found ) ;
#							Translate , to ^G
				while( $line =~ s/,\s*"([^"]*?),([^"]*?)"\s*,/,"$1$2",/g ) {
						$commas_found  = 'y' ;
					}
				$line =~ s/,\s*"(.*?)"\s*,/,$1,/g ;	#	Strip quotes
				@main::cells = split( /,/, $line ) ;
#							Translate ^G to ,
				if( defined $commas_found  ) {
					foreach ( @main::cells ) { s//,/g ; }
				}
			}
			else {
				@main::cells = split( /$sep/, $line ) ;
			}
			foreach ( @main::cells ) {
				s/^\s*(.*?)\s*$/$1/ ;
			}
			$return_value = 3 ;
		}
	}
	$return_value ;
}
#-------- Start the TX package for a new file ----------------------------------
sub start {
#
#	if  $TX::quiet is defined, messages turned off [ not recommended!! ]
#	if  $TX::debug is defined, debugging messages turned on
#
#		Is the filehandle already in use? 
	if( -r IN ) {
		close IN || die "Could not close $filename\n" ;
		unless( defined $quiet ) {
			print STDERR "Closed $filename\n" ;
		}
	}
	open( IN, $_[0] ) || die "Could not open $_[0]\n" ;
	$filename = $_[0] ;
	undef $column_definitions_read ;
	undef %main::col ;
	undef $altitude_unit ;
	$sep = "\t" ;	#	reset default - for spreadsheets
}
#-------------------------------------------------------------------------------
sub column_definitions {
	local( @cells ) = split( /$sep/, $line ) ;
	local( $cell_new ) ;
	local( $col_number ) = 0 ;
	foreach $cell ( @cells ) {
		if( $cell_new = &parse_column_definitions( $cell ) ) {
			if( defined $debug && defined $main::col{$cell_new} ) {
					print STDERR "Overwriting column definition ",
						"of $cell_new in column $main::col{$cell_new}\n",
						"     with that in column $col_number [ $cell ]\n"  ;
			}
			if( defined $debug ) {
				print STDERR "$cell_new = $col_number\n"  ;
			}
			$main::col{$cell_new} = $col_number ;
		}
		else {
			$main::unused_cells{$cell} = $col_number ;
		}
		++$col_number ;
	}
#	Needs check for redundant lat/lon definitions
#		e.g. lat_d and lat_r	
}
#-------------------------------------------------------------------------------
sub parse_column_definitions {
	local( $cell ) = $_[0] ;
	$cell =~ s/^\s*// ;
	$cell =~ s/\s*$// ;
	if   ( $cell =~ /^nam/i ) { $cell = 'NAM' ;}
#
#	   More complicated than need be, to skip over redundant decimal data in 
#			existing "Turnpoint Exchange" .tab files
#
	elsif( $cell =~ /^lon.*deg/i && $cell !~ /decimal/ ) {
		$cell = 'LON_D' ;
	}
	elsif( $cell =~ /^lon.*min/i && $cell !~ /decimal/ ) {
		$cell = 'LON_M' ;
	}
	elsif( $cell =~ /^lon.*sec/i ) { $cell = 'LON_S' ; }
	elsif( $cell =~ /^lon.*rad/i ) { $cell = 'LON_R' ; }
#
	elsif( $cell =~ /^lat.*deg/i && $cell !~ /decimal/ ) {
		$cell = 'LAT_D' ; 
	}
	elsif( $cell =~ /^lat.*min/i && $cell !~ /decimal/ ) {
		$cell = 'LAT_M' ;
	}
	elsif( $cell =~ /^lat.*sec/i ) { $cell = 'LAT_S' ; }
	elsif( $cell =~ /^lat.*rad/i ) { $cell = 'LAT_R' ; }
#
	elsif( $cell =~ /^cod/i      ) { $cell = 'COD'   ; }
	elsif( $cell =~ /^num/i      ) { $cell = 'NUM'   ; }
	elsif( $cell =~ /^tur/i      ) { $cell = 'TUR'   ; }
#	elsif( $cell =~ /^id.*?(\d+)*/i      ) {
	elsif( $cell =~ s/^id//i      ) {
		$cell =~ s/[\[\(\)\]]//g ;
		if( $cell =~ /(\d+)/ ) { $cell = 'ID_' . $1 ; }
		else     { $cell = 'ID' ; }
	}
	elsif( $cell =~ /^elev/i ) {
		if(    $cell =~ /feet/i )  { $main::altitude_unit = 'meters' ; }
		elsif( $cell =~ /meter/i ) { $main::altitude_unit = 'feet'; }
		$cell = 'ALT' ;
	}
	elsif( $cell =~ /^n(orth)*.*s(outh)*/i ) { $cell = "NS" ; }
	elsif( $cell =~ /^e(ast)*.*w(est)*/i   ) { $cell = "EW" ; }
	elsif( $cell =~ /^icao/i   ) { $cell = "ICAO" ; }
	elsif( $cell =~ /^CAI/i   ) {
		$cell = "\U$cell" ;
	}
#-------------------------------------------------------------------------------
#			Put in any other cells that the application wants to use here
#-------------------------------------------------------------------------------
	else {
		unless( defined $quiet ) {
			print STDERR "Column definition \"$cell\" not used\n" ;
		}
		undef $cell ;
	}
#
	$cell ;
}
#-------------------------------------------------------------------------------
sub file_definitions {
#
	if( defined $debug ) { print STDERR "File definition: $line\n" ; }
	$line =~ /^(\S.*?)$sep\s*(\S.*?)($sep|$)/ ;
	local( $key ) = $1 ;
	local( $value ) = $2 ;
	if( $key =~ /^sep/i ) {
		if( ! defined $quiet ) { print STDERR "SEPARATOR: $value\n" ; }
#			prepend \ in case the cell separator character is a meta-character
		$sep = '\\' . $value ;
	}
	else {$main::file_definitions{"\U$key"} = $value ; }	#	Render the key upper case
}
#-------------------------------------------------------------------------------
}	#	End of the TX package
1 ;