#!/usr/bin/perl -w
use strict;

# mbox_anal [-S]
#
# I suppose you could use this on things other than mbox, but
# it might not be of much use.  However, it doesn't really assume
# anything about the structure of the file(s) it opens.
#
# It analyses the input file(s) line by line.  It will keep track
# of how many lines exceed 78 characters in length (the recommended
# maximum length of a line in the RFCs), how many lines exceed
# 998 characters (at which point, mail services may chop the line
# or refuse to accept the message), how many lines have non-standard
# EOL behavior.
#
# The -S flag is used to print out summary stats.
#
# The applicable license for distributing this module, is that
# which is common across much of the perl world, that being you get
# to use your choice of either The Artistic License of perl,
# or the GPL.  You can find copies of the Artistic License at
# perl.com (and other places), and you can find copies of the GNU
# Public License at Gnu.org (and other places).
#
# Gordon Haverland, Matter Realisations, perl@materialisations.com
# 2003/05/11

use Getopt::Std;
use vars qw($opt_S);
getopts('S');

my(
   $fname,         # Name of file currently open
   $lineno,        # Line no of data in file
   $line,          # A line of data.
   $length,        # The string length of a line of data.
   $Illegal,       # Number of illegal length (> 998) lines
   $Unrecommended, # Number of excessive length (> 78) lines
   $non_rfc_eol,   # Flag for having seen non-RFC-2282 EOL behavior
   %EOL,           # Hash of EOL counters
   %hist,          # Hash of histogram data (geometric bin widths)
   );

while( $fname = shift( @ARGV ) ) {
    unless( -e $fname ) {
	print STDERR "Warning: $fname doesn't exist, skipping\n";
    }

    $lineno        = 0;
    $Illegal       = 0;
    $Unrecommended = 0;
    unless( open( MBOX, "< $fname" ) ) {
	print STDERR "Warning, Can't open $fname as mbox: $!\n";

    } else {
	while( $line = <MBOX> ) {
	    $lineno++;

	    $line = &examine_eol( $line );

	    $length = length( $line );
	    if( $length > 78 ) {
		if( $length > 988 ) {
		    &ma_warn( $fname, $lineno, "Illegal length $length" );
		    $Illegal++;

		} else {
		    &ma_warn( $fname, $lineno, "Unrecommended length $length" );
		    $Unrecommended++;
		}

		&build_hist( $length );
	    }

	}

	if( $opt_S ) {  # Spit out summary stats, if desired
	    if( $non_rfc_eol > 0 ) {  # Print out EOL stats
		print "End-of-Line behavior\n";
		print "RFC Compliant: $EOL{RFC}\n"     if( exists($EOL{RFC}) );
		print "UNIX EOL:      $EOL{UNIX}\n"    if( exists($EOL{UNIX}) );
		print "Macintosh EOL: $EOL{Mac}\n"     if( exists($EOL{Mac}) );
		print "QNX EOL:       $EOL{QNX}\n"     if( exists($EOL{QNX}) );
		print "NEL (EBCDIC?): $EOL{NEL}\n"     if( exists($EOL{NEL}) );
		print "Strange EOL:   $EOL{Strange}\n" if( exists($EOL{Strange}) );
	    }

	    $length = 0;
	    if( $Unrecommended > 0 ) {
		print "Excessive (unrecommended) line lengths on $Unrecommended lines\n";
		$length++;
	    }
	    if( $Illegal > 0 ) {
		print "Illegal line lengths on $Illegal lines\n";
		$length++;
	    }
	    if( $length > 0 ) {  # Print histogram
		print "Distribution of line lengths\n";
		print  "    Bin  Count\n";
		printf(" 79-102  %5d\n", $hist{' 79-102'})
		    if( exists( $hist{' 79-102'} ) );
		printf("103-131  %5d\n", $hist{'103-131'})
		    if( exists( $hist{'103-131'} ) );
		printf("132-169  %5d\n", $hist{'132-169'})
		    if( exists( $hist{'132-169'} ) );
		printf("170-218  %5d\n", $hist{'170-218'})
		    if( exists( $hist{'170-218'} ) );
		printf("219-281  %5d\n", $hist{'219-281'})
		    if( exists( $hist{'219-281'} ) );
		printf("282-362  %5d\n", $hist{'282-362'})
		    if( exists( $hist{'282-362'} ) );
		printf("363-466  %5d\n", $hist{'363-466'})
		    if( exists( $hist{'363-466'} ) );
		printf("467-601  %5d\n", $hist{'467-601'})
		    if( exists( $hist{'467-601'} ) );
		printf("602-774  %5d\n", $hist{'602-774'})
		    if( exists( $hist{'602-774'} ) );
		printf("775-998  %5d\n", $hist{'775-998'})
		    if( exists( $hist{'775-998'} ) );
		printf("   999+  %5d\n", $hist{'   999+'})
		    if( exists( $hist{'   999+'} ) );

	    }
	}

	close( MBOX );
    }
}

sub examine_eol {
    my $line = shift;

    if( $line =~ s/^(.*)\n\r$/$1/ ) {       # RFC-2822 email EOL
	# Do nothing, this is normal
	$EOL{RFC}++;

    } elsif( $line =~ s/^(.*)\n$/$1/ ) {    # UNIX EOL
	&ma_warn( $fname, $lineno, "UNIX EOL" );
	$EOL{UNIX}++;
	$non_rfc_eol++;

    } elsif( $line =~ s/^(.*)\r$/$1/ ) {    # Mac EOL
	&ma_warn( $fname, $lineno, "Mac EOL" );
	$EOL{Mac}++;
	$non_rfc_eol++;

    } elsif( $line =~ s/^(.*)\x1E$/$1/ ) {  # QNX EOL
	&ma_warn( $fname, $lineno, "QNX EOL" );
	$EOL{QNX}++;
	$non_rfc_eol++;

    } elsif( $line =~ s/^(.*)\x85$/$1/ ) {  # (EBCDIC NEL?) EOL
	&ma_warn( $fname, $lineno, "NEL EOL" );
	$EOL{NEL}++;
	$non_rfc_eol++;

    } else {                                # Bad EOL
	&ma_warn( $fname, $lineno, "Strange EOL" );
	$EOL{Strange}++;
	$non_rfc_eol++;
    }

    return( $line );
}
sub ma_warn {
    my $fname  = shift;
    my $lineno = shift;

    return if( $opt_S );  # User wants summary, not blow by blow

    if( $#_ == -1 ) {     # No reason
	print  "Warning: $fname($lineno)\n";
    } elsif( $#_ == 0 ) { # Reason given
	print  "Warning: $fname($lineno) - $_[0]\n";
    } else {
	die "Strange call to ma_warn\n";
    }
}
sub build_hist {
    my $length = shift;

    # Evenly space boundaries from ln(79) chars to ln(998) to make
    # a geometric progression for bin width.

    # Build up histogram.  ln(79)=4.37  ln(998)=6.91
    # 79-102, 103-131, 132-169, 170-218, 219-281, 282-362, 363-466,
    # 467-601, 602-774, 775-998, 998+
    if( $length < 103 ) { # We already know it's > 78
	$hist{' 79-102'}++;
    } elsif( $length < 132 ) {
	$hist{'103-131'}++;
    } elsif( $length < 170 ) {
	$hist{'132-169'}++;
    } elsif( $length < 219 ) {
	$hist{'170-218'}++;
    } elsif( $length < 282 ) {
	$hist{'219-281'}++;
    } elsif( $length < 363 ) {
	$hist{'282-362'}++;
    } elsif( $length < 467 ) {
	$hist{'363-466'}++;
    } elsif( $length < 602 ) {
	$hist{'467-601'}++;
    } elsif( $length < 775 ) {
	$hist{'602-774'}++;
    } elsif( $length < 998 ) {
	$hist{'775-998'}++;
    } else {
	$hist{'   999+'}++;
    }
}