#!/usr/bin/perl -w
# trim_space.pl - Don Yang (uguu.org)
#
# Trim leading/trailing white spaces and blank lines.
#
# 07/05/07

use strict;
my @lines = <>;

# Trailing whitespaces
foreach (@lines)
{
   chomp;
   s/\s*$//;
}

# Trailing blank lines
while( $#lines >= 0 )
{
   if( $lines[$#lines] =~ /^$/ )
   {
      pop @lines;
   }
   else
   {
      last;
   }
}

# Leading blank lines
while( $#lines >= 0 )
{
   if( $lines[0] =~ /^$/ )
   {
      shift @lines;
   }
   else
   {
      last;
   }
}

# Leading whitespaces
if( $lines[0] =~ /^(\s+)\S/ )
{
   my $max_leading_space = length($1);
   foreach (@lines)
   {
      next unless /^(\s*)\S/;
      if( length($1) < $max_leading_space )
      {
         $max_leading_space = length($1);
      }
   }
   for(my $i = 0; $i <= $#lines; $i++)
   {
      $lines[$i] = substr($lines[$i], $max_leading_space);
   }
}

print "$_\n" foreach @lines;