#!/usr/bin/env perl
# Shared with permission
use strict;
use warnings;

my @files = @ARGV;
die if ( not defined $files[0] );

foreach my $file (@files) {
    my ( $fh, $byte );
    open( $fh, "+<", "$file" ) or die "can't open flar";

    print "Searching for content_architectures at top of flar...\n";
    my ( $last_position, $current_position );
    while (<$fh>) {
        $current_position = tell($fh);
        if ( $current_position > 800 ) {
            print "ERROR: failed to find content_architectures...\n\n";
            exit;
        }
        if (/^content_architectures/) {
            last;
        }
        $last_position = $current_position;
    }
    print "Found line at byte $last_position to $current_position\n";

    my $lineLength  = $current_position - $last_position;
    my $valueLength = $lineLength - 23;
    if ( $valueLength < 5 ) {
        print
"ERROR: Can't replace value inline. Current value of content_architectures is too short.\n";
        exit;
    }
    my $numSpaces = $valueLength - 5;

    seek( $fh, $last_position + 22, 0 );
    sysread( $fh, $byte, $lineLength - 23 );

    print "Replacing \n";
    print "~~$byte~~\n";
    my $replacementString = "sun4v" . " " x $numSpaces;
    print "with\n";
    print "~~$replacementString~~\n";
    print "completed successfully.\n";
    seek( $fh, $last_position + 22, 0 );
    syswrite( $fh, $replacementString ) == $valueLength
      or die "write failed: $!\n";
    print "NEW HEADER:\n";
    seek( $fh, 0, 0 );

    while (<$fh>) {
        last if (/^begin/);
        print $_;
    }
    close $fh;
    print "\n";
}