#!/usr/bin/perl
# 
# Copyright © 2015-2020 by Vincent Slyngstad
# 
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
# 
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS LISTED ABOVE BE LIABLE
# FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
# 
# Except as contained in this notice, the names of the authors above
# shall not be used in advertising or otherwise to promote the sale, use
# or other dealings in this Software without prior written authorization
# from those authors.

@rem = '
@echo off
c:\perl5\bin\perl %0 %1 %2 %3 %4 %5 %6 %7 %8 %9
goto endofperl
@rem ' if @rem;

#
@todo = @ARGV;
@todo = (".") unless @todo;

#
# Returns TRUE if file should be in BIN format.
sub isBIN {
    return $_[0] =~ /-pb.*od$/ || $_[0] =~ /-ba.*od$/;
}

#
# Wander around finding directories named "Ok".
@Ok = (".");
while (@todo) {
    $dir = shift @todo;
    opendir(DIR, $dir) || die "$dir: $!";
#   print STDERR "Reading '$dir' ...";
    foreach (readdir(DIR)) {
    	$f = "$dir/$_";
	next if $_ eq ".";
	next if $_ eq "..";
	next if $_ eq "done";
	next unless -d $f;
	if (/^[Oo][Kk]/) {
	    push(@Ok, $f);
	    next;
	}
	push(@todo, $f);
	next;
    }
#   print STDERR "\n";
    closedir(DIR);
}

#
#
while (@todo) {
    $dir = shift @todo;
    # Don't check known RIM tapes, as they look
    # just like BIN tapes with a bad checksum.
    next if $dir =~ /-pm.od$/;
    &process($dir);
}

#
# Process each file.
sub process {
    local($f) = @_;
    #
    # Don't check known RIM tapes, as they look
    # just like BIN tapes with a bad checksum.
    return if $f =~ /-pm.od$/;
    #
    # Open the file and process it.
    open(INPUT, $f) || die "$f: $!";
    $sum = $c1 = $c2 = 0;
    return unless <INPUT> =~ /200/;
    while (<INPUT>) {
        $byte = oct($_);
	# Ignore Leader-Trailer
	# Uncomment to force single-segment tapes.
	#next if $byte == 0200;
	# If 377, ignore the comment.
        if ($byte == 0377) {
            while (<INPUT>) {
                $byte = oct($_);
#printf "Got Here %3o\n", $byte;
                last if $byte == 0377;
            }
            next;
        }
	if ($byte == 0200) {
	    # Leader trailer.  Must have check checksum.
	    # Remove the checksum bytes from the checksum
	    $sum -= $c1;
	    $sum -= $c2;
	    # Form the checksum from the tape image.
	    $c1 = ($c1<<6) + $c2;
	    # Checksum calcs are 12 bits.
	    $sum %= 010000;
	    #
	    # Bail if the sum is wrong.
	    if ($sum != $c1) {
	        printf STDERR "$f: Checksum is %04o not %04o\n", $sum, $c1;
	    } else {
		if ($sum) {
		    printf STDERR "Valid binary segment found in $f\n" 
			unless isBIN($f);
		}
	    }
	    $sum = $c1 = $c2 = 0;
	    next;
	}
	# If high bit on, better be a valid field setting.
        if ($byte&0200) {
            next if ($byte&0307) == 0300;
            printf STDERR "$f: not BIN format\n" if isBIN($f);
            return;
        }
	# High bit off, just add it to the checksum.
        $sum += $byte;
	# Remember the last two (checksum) bytes for later fixup.
	$c1 = $c2;
	$c2 = $byte;
    }
    warn "$f: odd byte count: ", tell(INPUT) if tell(INPUT) % 1;
    close(INPUT);
    # Remove the checksum bytes from the checksum
    $sum -= $c1;
    $sum -= $c2;
    # Form the checksum from the tape image.
    $c1 = ($c1<<6) + $c2;
    # Checksum calcs are 12 bits.
    $sum %= 010000;
    #
    # Bail if the sum is wrong.
    printf STDERR "$f: Checksum is %04o not %04o\n", $sum, $c1 if $sum != $c1;
}

#
# For "." and each directory named "Ok", process all the *.od files.
while (@Ok) {
    $dir = shift @Ok;
    opendir(DIR, $dir) || die "$dir: $!";
#   print STDERR "Reading '$dir' ...";
    foreach (readdir(DIR)) {
    	$f = "$dir/$_";
	next unless -f $f;
	next unless /\.od$/;
	&process($f);
    }
#   print STDERR "\n";
    closedir(DIR);
}


__END__
:endofperl