I am trying to build a flexible script that returns various SHA algorithms and string types.

I have it to the point where I am repeating very similar blocks of code, and I can't see a way to abstract them into a clean function call. I've gone down a couple of dead ends, and am just banging my head against a wall. Does anyone have any insights to share?

The full script is in my public scratchpad , but here are two examples of blocks I wish I could turn into one abstract function call: 


#
# There has to be a way to abstract these do_xxx blocks...
#

if ($do_sha1) {
   if (! open(FILE,"$fileName")) { print STDERR "$0 : cannot open file
+ \"$fileName\"\n"; return(0); }
   binmode FILE ;
   my $s1 = Digest::SHA->new(1) ;
   my $sha1;
   if ($family{sha1}) {
      $s1->addfile(*FILE);
      $sha1 = $s1->digest;
      my $ps = unpack("B*",$sha1);
      while (length($ps) < 160) { $ps = "0$ps"; }
      print "sha1($fileName)= $ps\n";
      seek(FILE,0,0);
   }
   # The block above seeks back to start-of-file, 
   # because addfile(*FILE) needs to reread the data,
   # but that's horrible! 
   # I don't know if I can slurp it all into a variable, though...
   if ($family{sha1_hex}) {
      $s1->addfile(*FILE);
      $sha1 = lc($s1->hexdigest);
      if ($opt_u) { $sha1 = uc($sha1); }
      print "sha1_hex($fileName)= $sha1\n";
      seek(FILE,0,0);
   }
   if ($family{sha1_b64}) {
      $s1->addfile(*FILE);
      $sha1 = $s1->b64digest;
        while (length($sha1) % 4) { $sha1 .= '='; }
      print "sha1_b64($fileName)= $sha1\n";
   }
   close(FILE);
}


if ($do_256) {
   if (! open(FILE,"$fileName")) { print STDERR "$0 : cannot open file
+ \"$fileName\"\n"; return(0); }
   binmode FILE ;
   my $s256 = Digest::SHA->new(256) ;
   my $sha256;
   if ($family{sha256}) {
      $s256->addfile(*FILE);
      $sha256 = $s256->digest;
      my $ps = unpack("B*",$sha256);
      while (length($ps) < 160) { $ps = "0$ps"; }
      print "sha1($fileName)= $ps\n";
      seek(FILE,0,0);
   }
   if ($family{sha256_hex}) {
      $s256->addfile(*FILE);
      $sha256 = lc($s256->hexdigest);
      if ($opt_u) { $sha256 = uc($sha256); }
      print "sha256_hex($fileName)= $sha256\n";
      seek(FILE,0,0);
   }
   if ($family{sha256_b64}) {
      $s256->addfile(*FILE);
      $sha256 = $s256->b64digest;
        while (length($sha256) % 4) { $sha256 .= '='; }
      print "sha256_b64($fileName)= $sha256\n";
   }
   close(FILE);
}

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In reply to Can I abstract these blocks into a function call? by dwhite20899

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