#!/usr/bin/perl

use File::Rdiff qw(:trace :nonblocking);

trace_level(LOG_INFO);

if ($ARGV[0] eq "signature") {
   open $basis, "<", $ARGV[1]
      or die "$ARGV[1]: $!";
   open $sig, ">", $ARGV[2]
      or die "$ARGV[2]: $!";

   my $job = new_sig File::Rdiff::Job 128;
   my $buf = new File::Rdiff::Buffers 4096;

   while ($job->iter($buf) == BLOCKED) {
      # fetch more input data
      $buf->avail_in or do {
         my $in;
         65536 == sysread $basis, $in, 65536 or $buf->eof;
         $buf->in($in);
      };
      print $sig $buf->out;
   }
   print $sig $buf->out;

} elsif ($ARGV[0] eq "delta") {
   open $sig,   "<$ARGV[1]" or die "$ARGV[1]: $!";
   open $new,   "<$ARGV[2]" or die "$ARGV[2]: $!";
   open $delta, ">$ARGV[3]" or die "$ARGV[3]: $!";

   # first load the signature into memory
   my $job = new_loadsig File::Rdiff::Job;
   my $buf = new File::Rdiff::Buffers 0;

   do {
      $buf->avail_in or do {
         my $in;
         65536 == sysread $sig, $in, 65536 or $buf->eof;
         $buf->in($in);
      };
   } while $job->iter($buf) == BLOCKED;

   $sig = $job->signature;

   $sig->build_hash_table;

   # now create the delta file
   my $job = new_delta File::Rdiff::Job $sig;
   my $buf = new File::Rdiff::Buffers 65536;

   do {
      $buf->avail_in or do {
         my $in;
         65536 == sysread $new, $in, 65536 or $buf->eof;
         $buf->in($in);
      };
      print $delta $buf->out;
   } while $job->iter($buf) == BLOCKED;
   print $delta $buf->out;

} elsif ($ARGV[0] eq "patch") {
   open $base,  "<$ARGV[1]" or die "$ARGV[1]: $!";
   open $delta, "<$ARGV[2]" or die "$ARGV[2]: $!";
   open $new,   ">$ARGV[3]" or die "$ARGV[3]: $!";

   # NYI
   File::Rdiff::patch_file $base, $delta, $new;
} else {
   print <<EOF;
$0 signature BASIS SIGNATURE
$0 delta SIGNATURE NEW DELTA
$0 patch BASE DELTA NEW
EOF
   exit (1);
}