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egs/wsj/s5/utils/create_data_link.pl 3.67 KB
8dcb6dfcb   Yannick Estève   first commit
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  #!/usr/bin/env perl
  
  # Copyright 2013  Guoguo Chen
  #           2014  Johns Hopkins University (author: Daniel Povey)
  # Apache 2.0.
  #
  # This script distributes data onto different file systems by making symbolic
  # links. It is supposed to use together with utils/create_split_dir.pl, which
  # creates a "storage" directory that links to different file systems.
  #
  # If a sub-directory egs/storage does not exist, it does nothing. If it exists,
  # then it selects pseudo-randomly a number from those available in egs/storage/*
  # creates a link such as
  #
  #   egs/egs.3.4.ark -> storage/4/egs.3.4.ark
  #
  use strict;
  use warnings;
  use File::Basename;
  use File::Spec;
  use Getopt::Long;
  
  sub GetGCD {
    my ($a, $b) = @_;
    while ($a != $b) {
      if ($a > $b) {
        $a = $a - $b;
      } else {
        $b = $b - $a;
      }
    }
    return $a;
  }
  
  my $Usage = <<EOU;
  create_data_link.pl:
  This script distributes data onto different file systems by making symbolic
  links. It is supposed to use together with utils/create_split_dir.pl, which
  creates a "storage" directory that links to different file systems.
  
  If a sub-directory foo/storage does not exist, it does nothing. If it exists,
  then it selects pseudo-randomly a number from those available in foo/storage/*
  creates a link such as
  
    foo/egs.3.4.ark -> storage/4/egs.3.4.ark
  
  Usage: utils/create_data_link.pl <data-archive1> [<data-archive2> ... ]
   e.g.: utils/create_data_link.pl foo/bar/egs.3.4.ark foo/bar/egs.3.5.ark
   (note: the dirname, e.g. foo/bar/, must be the same in all cases).
  
  See also utils/remove_data_links.sh
  EOU
  
  GetOptions();
  
  if (@ARGV == 0) {
    die $Usage;
  }
  
  my $example_fullpath = $ARGV[0];
  
  # Check if the storage has been created. If so, do nothing.
  my $dirname = dirname($example_fullpath);
  if (! -d "$dirname/storage") {
    exit(0);
  }
  
  # Storage exists, create symbolic links in the next few steps.
  
  # First, get a list of the available storage directories, and check if they are
  # properly created.
  opendir(my $dh, "$dirname/storage/") || die "$0: Fail to open $dirname/storage/
  ";
  my @storage_dirs = grep(/^[0-9]*$/, readdir($dh));
  closedir($dh);
  my $num_storage = scalar(@storage_dirs);
  for (my $x = 1; $x <= $num_storage; $x++) {
    (-d "$dirname/storage/$x") || die "$0: $dirname/storage/$x does not exist
  ";
  }
  
  # Second, get the coprime list.
  my @coprimes;
  for (my $n = 1; $n <= $num_storage; $n++) {
    if (GetGCD($n, $num_storage) == 1) {
      push(@coprimes, $n);
    }
  }
  
  my $ret = 0;
  
  foreach my $fullpath (@ARGV) {
    if ($dirname ne dirname($fullpath)) {
      die "Mismatch in directory names of arguments: $example_fullpath versus $fullpath";
    }
  
    # Finally, work out the directory index where we should put the data to.
    my $basename = basename($fullpath);
    my $filename_numbers = $basename;
    $filename_numbers =~ s/[^0-9]+/ /g;
    my @filename_numbers = split(" ", $filename_numbers);
    my $total = 0;
    my $index = 0;
    foreach my $x (@filename_numbers) {
      if ($index >= scalar(@coprimes)) {
        $index = 0;
      }
      $total += $x * $coprimes[$index];
      $index++;
    }
    my $dir_index = $total % $num_storage + 1;
  
    # Make the symbolic link.
    if (-e $fullpath) {
      unlink($fullpath);
    }
    if (symlink("storage/$dir_index/$basename", $fullpath) != 1) { # failure
      $ret = 1;  # will exit with error status.
    }
  }
  
  exit($ret);
  
  ## testing:
  # rm -rf foo bar
  # mkdir -p bar/{1,2,3,4}
  # mkdir -p foo/storage
  # for x in 1 2 3 4; do ln -s ../../bar/$x foo/storage/$x; done
  # utils/create_data_link.pl utils/create_data_link.pl foo/1.3.ark  foo/2.3.ark
  # ls -l foo
  # total 0
  # lrwxrwxrwx 1 dpovey fax 17 Sep  2 17:41 1.3.ark -> storage/3/1.3.ark
  # lrwxrwxrwx 1 dpovey fax 17 Sep  2 17:41 2.3.ark -> storage/4/2.3.ark
  # drwxr-xr-x 2 dpovey fax 38 Sep  2 17:40 storage