Added hash-mode: MurmurHash

2021-05-18 10:58:13 +02:00
parent 10d0dde55c
commit aa7c579736
7 changed files with 1241 additions and 0 deletions
@@ -0,0 +1,148 @@
+#!/usr/bin/env perl
+
+##
+## Author......: See docs/credits.txt
+## License.....: MIT
+##
+
+use strict;
+use warnings;
+
+sub module_constraints { [[0, 256], [8, 8], [0, 55], [8, 8], [-1, -1]] }
+
+sub MurmurHash
+{
+  use integer;
+
+  my $word = shift;
+  my $seed = shift;
+
+  # https://tanjent.livejournal.com/756623.html
+
+  my $m = 0x7fd652ad;
+  my $r = 16;
+
+  my $hash = $seed;
+
+  $hash += 0xdeadbeef;
+
+  my @chars = unpack ("c*", $word);
+
+  my $len = length $word;
+
+  my $i;
+
+  for ($i = 0; $i < $len - 3; $i += 4)
+  {
+    my $c0 = $chars[$i + 0];
+    my $c1 = $chars[$i + 1];
+    my $c2 = $chars[$i + 2];
+    my $c3 = $chars[$i + 3];
+
+    my $l = ($c0 <<  0)
+          | ($c1 <<  8)
+          | ($c2 << 16)
+          | ($c3 << 24);
+
+    $hash += $l;
+    $hash *= $m;
+    $hash ^= ($hash & 0xffffffff) >> $r;
+  }
+
+  my $rem = $len & 3;
+
+  if ($rem == 3)
+  {
+    my $c0 = $chars[$i + 0];
+    my $c1 = $chars[$i + 1];
+    my $c2 = $chars[$i + 2];
+    my $c3 = 0;
+
+    my $l = ($c0 <<  0)
+          | ($c1 <<  8)
+          | ($c2 << 16)
+          | ($c3 << 24);
+
+    $hash += $l;
+    $hash *= $m;
+    $hash ^= ($hash & 0xffffffff) >> $r;
+  }
+  elsif ($rem == 2)
+  {
+    my $c0 = $chars[$i + 0];
+    my $c1 = $chars[$i + 1];
+    my $c2 = 0;
+    my $c3 = 0;
+
+    my $l = ($c0 <<  0)
+          | ($c1 <<  8)
+          | ($c2 << 16)
+          | ($c3 << 24);
+
+    $hash += $l;
+    $hash *= $m;
+    $hash ^= ($hash & 0xffffffff) >> $r;
+  }
+  elsif ($rem == 1)
+  {
+    my $c0 = $chars[$i + 0];
+    my $c1 = 0;
+    my $c2 = 0;
+    my $c3 = 0;
+
+    my $l = ($c0 <<  0)
+          | ($c1 <<  8)
+          | ($c2 << 16)
+          | ($c3 << 24);
+
+    $hash += $l;
+    $hash *= $m;
+    $hash ^= ($hash & 0xffffffff) >> $r;
+  }
+
+  $hash *= $m;
+  $hash ^= ($hash & 0xffffffff) >> 10;
+  $hash *= $m;
+  $hash ^= ($hash & 0xffffffff) >> 17;
+
+  return $hash & 0xffffffff;
+}
+
+sub module_generate_hash
+{
+  my $word = shift;
+  my $salt = shift;
+
+  my $salt_bin = pack ("H*", $salt);
+
+  my $seed = unpack ("N", $salt_bin); # or maybe "L" ? not enought example data to clarify
+
+  my $digest = MurmurHash ($word, $seed);
+
+  my $hash = sprintf ("%08x:%08x", $digest, $seed);
+
+  return $hash;
+}
+
+sub module_verify_hash
+{
+  my $line = shift;
+
+  my ($hash, $salt, $word) = split (':', $line);
+
+  return unless defined $hash;
+  return unless defined $word;
+  return unless defined $salt;
+
+  return unless length $hash == 8;
+  return unless length $salt == 8;
+
+  my $word_packed = pack_if_HEX_notation ($word);
+
+  my $new_hash = module_generate_hash ($word_packed, $salt);
+
+  return ($new_hash, $word);
+}
+
+1;
+