1 files changed, 161 insertions, 0 deletions
diff --git a/midisep.pl b/midisep.pl
new file mode 100755
index 0000000..ebd2f9d
--- /dev/null
+++ b/midisep.pl
@@ -0,0 +1,161 @@
+#!/usr/bin/perl 
+use Data::Dumper;
+use Cwd;
+
+our $DEBUG = 1;
+
+our $MIDICSV_BIN = Cwd::abs_path("midicsv-1.1/midicsv");
+our $CSVMIDI_BIN = Cwd::abs_path("midicsv-1.1/csvmidi");
+
+our $CHANNEL_EVENTS = [ 
+  'Note_on_c', 'Note_off_c', 'Pitch_bend_c', 'Control_c', 
+  'Program_c', 'Channel_aftertouch_c', 'Poly_aftertouch_c',
+];
+
+our $SYSEX_EVENTS = [
+  'System_exclusive', 'System_exclusive_packet'
+];
+
+
+sub usage{
+  print STDERR sprintf('$>%s midifile [output_dir]'."\n", $0);
+  exit 1;
+}
+
+
+
+sub error{
+  my $msg = shift;
+  print STDERR $msg . "\n";
+  exit(1);
+}
+
+sub warn_sysex_found{
+  my $event = shift;
+  my $warning = sprintf("Sysex event found on channel %s\n", $event->{channel});
+  print STDERR $warning;
+}
+
+
+sub correct_bad_note_ons{
+  my $event = shift;
+  if ($event->{type} =~ /Note_on/i && $event->{data}->[-1] == 0) {
+    $event->{type} = "Note_off_c";
+    $event->{data}->[2] =~ s/on/off/i; 
+  }
+  return $event;
+}
+
+sub file_to_list{
+  my $file = shift;
+  my $total_channels = shift;
+  my $csvdata = `$MIDICSV_BIN $file`;
+  my $list = [ 
+    map { 
+      chomp($_); 
+      my $ctx = {};
+
+      my $line = [ split(',', $_ ) ]; 
+      $ctx->{data} = $line;
+      $ctx->{type} = $line->[2];
+      if (grep { $ctx->{type} =~ /$_/i } @$CHANNEL_EVENTS ){
+        $ctx->{channel} = ($line->[3] =~ m/([0-9]+)/g)[0];
+        if (!(grep { $ctx->{channel} == $_ } @$total_channels )){
+          push(@$total_channels, $ctx->{channel});
+        }
+      }
+#      [ @line ]; 
+      $ctx;
+    } split('\n', $csvdata) ];
+  return $list;
+}
+
+sub add_to_all_outputs{
+  my $event = shift;
+  my $output_files = shift;
+  foreach my $events (values %$output_files){
+    push (@$events, join(',' , @{$event->{data}}));
+  };
+}
+
+sub add_to_single_output{
+  my $event = shift;
+  my $output_files = shift;
+  push(@{$output_files->{$event->{channel}}}, join(',', @{$event->{data}}));
+}
+
+
+sub process_event_list{
+  my $event_list = shift;
+  my $total_channels = shift;
+  my $output_data = {};
+
+  if ($event_list->[0]->{type} !~ /header/i){
+    error("Bad header");
+  }
+  #marker header as type0 
+  $event_list->[0]->{data}->[3] =~ s/[0-9]+/0/g;
+
+  #check if file has more than one track/composition
+  my $tracks_count = $header->{data}->[4];
+  if ($tracks_count > 1){
+    error("Multiple tracks in same file, not yet implemented.");
+  }
+  foreach my $channel(@$total_channels){
+    $output_data->{$channel} = [];
+  }
+
+  #main loop
+  foreach $event(@$event_list){
+    if ( grep { $event->{type} =~ /$_/i } @$CHANNEL_EVENTS ){
+      $event = correct_bad_note_ons($event);
+      add_to_single_output( $event, $output_data );
+    }
+    elsif ( grep { $event->{type} =~ /$_/i} @$SYSEX_EVENTS ){
+      #consider adding special handle for sysex events
+      #currently just ignores them
+      warn_sysex_found ($event); 
+    }
+    else {
+      add_to_all_outputs( $event, $output_data);
+    }
+  };
+
+  return $output_data;
+}
+
+
+sub data_to_files{
+  my $output_data = shift;
+  my $filename_prefix = shift;
+  foreach my $channel (keys %$output_data){
+    my $midi_filename = sprintf("%s-%s.mid", $filename_prefix, $channel);
+    my $csv_filename = sprintf("/tmp/%s-%s.csv", $filename_prefix, $channel);
+    open F, ">$csv_filename" or die $!;
+    print F (join("\n", @{$output_data->{$channel}}));
+    close(F);
+    system("$CSVMIDI_BIN $csv_filename $midi_filename");
+    unlink($csv_filename);
+  }
+}
+
+sub main{
+  if (scalar(@ARGV) < 1){
+    if ($DEBUG){
+      print STDERR "DEBUG: using example.mid as default midifile\n";
+    }else{
+      usage;
+    }
+  }
+  
+  my $file = $ARGV[0] || "example.mid";
+  my $output_dir = $ARGV[2] || "./";
+  our $total_channels = [];
+
+  our $filename_prefix = $output_dir . ($file =~ m/^(.+)\./g)[0];
+  my $event_list = file_to_list ($file, $total_channels);
+  my $output_data = process_event_list ($event_list, $total_channels); 
+  data_to_files($output_data, $filename_prefix);
+#  
+};
+main;