# UPDATE!!!!  - After downloading, I noticed that this script didn't 
#               work any longer. Problem was, that additional CR's 
#               were added to the __DATA__ section.
#               Adding s/\x0d//g; to extract_csv_entries() fixed 
#               this problem under Linux.  
               
# TODO:
# [ ] use files instead of DATA
# [ ] use a CPAN module to parse CSV files
# [ ] simplify / it is much easier if all files can be hold in memory:
#      - read second file to $file2_data{$key}=$value
#      - then do something along:
#         @result = map { exists $file2_data{$_} ? $file2_data{$_} 
#                                                : "0" 
#                       } @ordered_items;
 
use strict;

my %file1_data;      # $file1_data{key} = value of last column
my @ordered_items;   # preserves order of keys from first file
my $expected_no_of_entries = 10; # expected entries in a CSV line


sub extract_csv_entries {
  # in a real world program, one would use a CSV module from CPAN...
  my $line = shift;

  # NOTE: maybe you need to remove the next line under Windows/Mac?
  $line =~ s/\x0d//g; 
  my @csv_items = split /;/, $line;

  if (@csv_items != $expected_no_of_entries) {
     die "illegal number of entries: $line ... \n";
  }

  return @csv_items[0,-1]; # first & last entry
}


sub compare_file { # here, we simulate to read from files...
  my $expect  = 0;
  my @result;

  while (<DATA>) {
    next if /^\s*$/;
    last if /^EOF/;
    chomp;

    my ($key,$value) = extract_csv_entries($_);
    if (exists $file1_data{$key}) {
# Update: uncomment these lines to ensure that
#         entries are the same as in 1st file...
#       if ($file1_data{$key} ne $value) { # ensure val's didn't chang
+e
#          die "enties for $key differ: $file1_data{$key} <=> $value";
#       }
    } else {
       die "item found that is not in first file: $key / $value\n";
    }
    
    # advance expected key until match 
    while ($key ne $ordered_items[$expect++]) {
      push(@result,0);
    }

    push(@result, $value); # finally in sync.
  }

  # EOF before last expected key? Pad with zeros...
  push(@result,0) for ($expect..$#ordered_items);

  if (@result != @ordered_items) { # paranoia
     die("internal error: " . join(";", @result));
  }

  return \@result;
}


sub print_result {
  my ($file_no, $aref) = @_;
  print "File  $file_no: ", join("; ", @{$aref}), "\n";
}


# Step 1 - learn the key/value pairs and key-order
# read the first "file" (emulated here)
while (<DATA>) {
  next if /^\s*$/;   # skip empty lines
  last if /^EOF/;    # emulate eof
  chomp;
  
  my ($key,$value)  = extract_csv_entries($_);
  push @ordered_items, $key;   # learn order from first file
  $file1_data{$key} = $value;  # finally learn key/value
}


# print the list of items for 1st file in original order
print "Entries: ", join (";", @ordered_items), "\n";
print_result(1, [ (map { $file1_data{$_} } @ordered_items) ]);

# now compare some sample files...
for my $file_no (2..5) { 
  print_result($file_no, compare_file() );
}


__DATA__

DISTINGUERE TRA;1;14;507;0,000000242475382686773;0,0000033946553576148
+2;0,000122935019022194;0,00000000041732202096217;9,18246152003019;9,1
+8246152003019
MANCANTE DI;1;56;507;0,000000242475382686773;0,0000135786214304593;0,0
+00122935019022194;0,00000000166928808384868;7,18246152003019;7,182461
+52003019
APPLICARE SU;1;64;507;0,000000242475382686773;0,0000155184244919535;0,
+000122935019022194;0,00000000190775781011278;6,9898164420878;6,989816
+4420878
MONTATO IN;1;78;507;0,000000242475382686773;0,0000189130798495683;0,00
+0122935019022194;0,00000000232507983107495;6,70441422322555;6,7044142
+2322555
IMPIEGATO IN;2;180;507;0,000000484950765373545;0,0000436455688836191;0
+,000122935019022194;0,00000000536556884094218;6,49796334575812;12,995
+9266915162
RAGGRUPPARE IN;1;109;507;0,000000242475382686773;0,0000264298167128582
+;0,000122935019022194;0,00000000324915002034832;6,22163211731087;6,22
+163211731087
EOF of first file

DISTINGUERE TRA;1;14;507;0,000000242475382686773;0,0000033946553576148
+2;0,000122935019022194;0,00000000041732202096217;9,18246152003019;9,1
+8246152003019
APPLICARE SU;1;64;507;0,000000242475382686773;0,0000155184244919535;0,
+000122935019022194;0,00000000190775781011278;6,9898164420878;6,989816
+4420878
MONTATO IN;1;78;507;0,000000242475382686773;0,0000189130798495683;0,00
+0122935019022194;0,00000000232507983107495;6,70441422322555;6,7044142
+2322555
IMPIEGATO IN;2;180;507;0,000000484950765373545;0,0000436455688836191;0
+,000122935019022194;0,00000000536556884094218;6,49796334575812;12,995
+9266915162
EOF of second file

DISTINGUERE TRA;1;14;507;0,000000242475382686773;0,0000033946553576148
+2;0,000122935019022194;0,00000000041732202096217;9,18246152003019;me 
+differs!
RAGGRUPPARE IN;1;109;507;0,000000242475382686773;0,0000264298167128582
+;0,000122935019022194;0,00000000324915002034832;6,22163211731087;6,22
+163211731087
EOF of dummy third file

MONTATO IN;1;78;507;0,000000242475382686773;0,0000189130798495683;0,00
+0122935019022194;0,00000000232507983107495;6,70441422322555;6,7044142
+2322555
EOF of dummy fourth file

MONTATO INorOUTorWhatever;1;78;507;0,000000242475382686773;0,000018913
+0798495683;0,000122935019022194;0,00000000232507983107495;6,704414223
+22555;6,70441422322555
EOF of illegal fifth file with illegal entry
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