#!/usr/local/bin/perl

###
### created by: JSC
### version:    1.1
### initial:    28.06.2003
### changelog:  28.07.2003 JSC
###             * input vs. idx file relation fixed
###

my ($in,$aFrame,$bFrame,$out) = ("","");
my ($firstR,$curR,$aR,$bByte,$idy) = (0,0,0,0,"");
my $inidx = "";

sub usage(){
   die "Error: $_[0]\nUsage: $0 infile startframe stopframe outfile\n".
       "   infile     - A NuppelVideo file as input. The corresponding index file\n".
       "                should be named \"infile.idx\".\n".
       "                You can simple choose a index file as infile.\n".
       "   outfile    - The output file in NuppelVideo format. Should not exist.\n".
       "   startframe - the first wanted frame\n".
       "   stopframe  - the last wanted frame\n\n";
}

$in     = shift @ARGV;
$aFrame = shift @ARGV;
$bFrame = shift @ARGV;
$out    = shift @ARGV;

&usage("can't read infile \"$in\"")              if( ! -r "$in" );
&usage("2. parameter should be a number or '-'") if( $aFrame !~ /^(-|\d+)$/ );
&usage("3. parameter should be a number or '-'") if( $bFrame !~ /^(-|\d+)$/ );
&usage("$out already exist")                     if( -r "$out" );

$inidx = "${in}.idx";

{ # check for index file as infile
  my $buffer;
   open(IN,"< $in") or die;
   $_ = sysread(IN,$buffer,5);
   die "short read ($_)" if( $_ != 5 );
   if( $buffer eq "ADNV\n" ){
      print "infile is a NuppelVideo index file\n";
      $_ = sysread(IN,$buffer,2048);      # $MAXPATH + $MAXFILE + some extra
      die "short read ($_)" if( $_ < 9 ); # min: "File: a\n"
      $buffer =~ s/^File: //;
      $buffer =~ s/\n.*//s;
      $inidx = $in;
      $in    = $buffer;
      print "infile now $in\n";
   }
   close(IN);
}

if( -r "$inidx" ){
  my $fnum = 0;
  my ($fR,$cR) = (0,0);
  my ($aB,$bB) = (0,0);
  my $AudioSection = 0;
   open(IN,"< $inidx") or die;
   while( <IN> ){
      # a lost V-frame is named L-frame and replaced by it's previous frame
      # * we have:
      #   * 3% chance to have a droped frame after a R-frame
      #   * < 0,1% droped frames
      #   * no problem for end-cut
      #   = 3% * 0,1% = 0.003% probability for a L-frame direct after R-frame
      # * if we cut (start-cut) before a L-frame, we loose all following frames
      #   until a valid V-frame
      if( /^Comp:[1L]  Pos :(\d+)/ ){
        my $pos = $1 - 12;
         if( $fnum == $aFrame ){
            $aB = $pos;
         }
         if( $fnum == $bFrame + 1){
            $bB = $pos;
         }
         $fnum++;
      }
      $AudioSection = 1 if( /^Audio :/ );
      $AudioSection = 0 if( /^RSync :/ );
      next if( $AudioSection );
      if( /^Comp:R  Pos :(\d+)/ ){
        my $pos = $1 -12;
         if( $fR == 0 ){
            $fR = $pos;
         }else{
            $cR = $pos if( $pos < $aB );
         }
      }
   }
   close(IN);
   $firstR=$fR;
   $aR=$cR;
   $bByte=$bB;
}

{ # error check and parameter consolidation
  my $msg = "can't cut: 0-$firstR $aR-$bByte\n";
   die $msg if( $firstR == 0 );
   if( $aFrame != "-" ){
      die $msg if( $aR <= $firstR );
   }else{
      $aR = $firstR;
   }
   if( $bFrame != "-" ){
      die $msg if( $bByte <= $aR );
   }else{
      @_ = stat $in;
      die "can't stat $in: $!" if( $#_ == -1 );
      $bByte = $_[7];
   }
}

my $buffer;
open(IN,"< $in")   or die "can't open \"$in\" for reading";
open(OUT,"> $out") or die "can't open \"$out\" for writing";

# copy trailer up to first R-frame
$_ = sysread(IN,$buffer,$firstR);
die "short read ($_)" if( $_ != $firstR );
$_ = syswrite(OUT,$buffer,$firstR);
die "short write ($_,$!)" if( ! defined $_ or $_ != $firstR );

# copy the movie
die "can't seek: $!" if( seek(IN,$aR,0) == 0);
my $cur = $aR;
my $len;
while( $cur < $bByte ){
   $len = sysread(IN,$buffer,1000000);
   die "eof found cur=$cur bByte=$bByte len=$len" if( $len == 0);
   die "error"     if( $len < 0 );
   $len = $bByte - $cur if( $cur + $len > $bByte );
   $_ = syswrite(OUT,$buffer,$len);
   die sprintf("short write ($_,%d)",$!) if( ! defined $_ or $_ != $len );
   $cur += $len;
}

close(OUT);
close(IN);

exit(0);