String::Ediff - Produce common sub-string indices for two strings

  use String::Ediff;
  my $s1 = "hello world";
  my $s2 = "hxello worlyd";

  my $indices = String::Ediff::ediff($s1, $s2);
  print $indices, "\n"; #1 10 0 0 2 11 0 0

  #                           0         1         2        0         1         2
  #                           01234567890123456789012345   012345678901234567890123
  print String::Ediff::ediff("hello world a hello world", "hxello worlyd xyz hello");
  # 1 10 0 0 2 11 0 0 13 20 0 0 17 23 0 0

This module uses suffix tree algorithm to determine the common substrings.

  $common_sub_string_indices = ediff($s1, $s2);

The ediff method takes two strings and returns the common sub-string indices between the two strings. The returned indices consists of records separated by a space. Each record, representing one common sub-string, consists of 8 numbers in the following format:

  bc1 ec1 bl1 el1 bc2 ec2 bl2 el2

bc1 - begin char in s1

ec1 - end char in s1

bl1 - begin line in s1

el1 - end line in s1

bc2 - begin char in s2

ec2 - end char in s2

bl2 - begin line in s2

el2 - end line in s2

  1. white spaces are ignored.
  2. because of white spaces are ignored, the end char index of a previous
     record and the begin char index of a next record might overlap.
  3. the interval is right open-ended, i.e. [1, 4) means char 1, 2, and 3
     are in the common string.  char 4 is not.
  4. only sub-string with size >= 4 are recorded.

Bo Zou, boxzou@yahoo.com

Copyright (C) 2003-2005 Bo Zou

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.