#!/App/Perl/bin/perl -w
#
# map_info1.pl
#
# Perl script to output the information for a map grid location.
#
# (c) Copyright 2000 by Clint Goss, All Rights Reserved.

use strict 'vars';

# Pick up our options

use Getopt::Std;
use vars qw($opt_d $opt_D $opt_f $opt_h $opt_p $opt_v);
if (! getopts("dDf:hp:v")) { &usage(); exit; }

sub usage {
	print <<END_OF_HELP;
usage: $0 [options]

Produce the information for a map grid location.

Options:
  -d		Turn on moderate debugging
  -D		Turn on very verbose debugging
  -f FILE	Specify the map grid database file. Default is map_grid.db
  -h		Print this help message
  -p RxC	Position (required!).
		The R and C are Row and column positions (zero-based).
		  For example, -p 0x17 indicates the first row, 18th column.
  -v		Turn on verbose reporting mode
END_OF_HELP
}

if ($opt_h) { &usage(); exit; }

# Parameters to this program

my ($debug) = $opt_D ? 2 : ($opt_d ? 1 : 0);
my ($mapGridFilename) = $opt_f ? $opt_f : "map_grid.db";
my ($verbose) = $opt_v;

# Parse the required -p position parameter

my ($position) = $opt_p;
if (! $position) { &usage(); exit; }
my ($rowPosition, $colPosition) = split ("x", $position);
if (! $rowPosition) { &usage(); exit; }
if (! $colPosition) { &usage(); exit; }

# Open the input file.

open (MAP_GRID, "<$mapGridFilename") || die "Can't open $mapGridFilename: $!";

# Pick up the number of rows.

my ($header);
read (MAP_GRID, $header, 2) || die "Can't read $mapGridFilename: $!";
my ($rowCount, $colCount) = unpack ("cc", $header);

# Standard sizes in the file.

my ($headerByteCount) = 10;
my ($bytesPerFileName) = 20;

# Pick up the four file names.

my ($file_A_0) = &mapFileName ($rowPosition, $colPosition,
			$rowCount, $colCount);

my ($file_A_1) = &mapFileName ($rowPosition, $colPosition + 1,
			$rowCount, $colCount);

my ($file_B_0) = &mapFileName ($rowPosition + 1, $colPosition,
			$rowCount, $colCount);

my ($file_B_1) = &mapFileName ($rowPosition + 1, $colPosition + 1,
			$rowCount, $colCount);

# Produce the output for this program

printf "Map files: %s %s\n", $file_A_0, $file_A_1;
printf "Map files: %s %s\n", $file_B_0, $file_B_1;

close MAP_GRID;
exit;

# Read a single file name at a given row and column position from MAP_GRID.

sub mapFileName {
	my ($rowPos, $colPos, $rowCount, $colCount) = @_;

	# Move the file pointer to the start of the file name.

	seek (MAP_GRID,
		$headerByteCount +
			(($rowPos*$colCount) + $colPos) * $bytesPerFileName,
		0);

	# Read the file name and strip any blanks.

	my ($filename);
	read (MAP_GRID, $filename, $bytesPerFileName)
			|| die "Can't read $mapGridFilename: $!";

	$filename =~ s/^\s+//;
	$filename =~ s/\s+$//;
	return $filename;
}