ona  18.1.1
About: OpenNetAdmin provides a database managed inventory of your IP network (with Web and CLI interface).
  Fossies Dox: ona-18.1.1.tar.gz  ("inofficial" and yet experimental doxygen-generated source code documentation)  

_DiffEngine Class Reference

Public Member Functions

 diff ($from_lines, $to_lines)
 
 _diag ($xoff, $xlim, $yoff, $ylim, $nchunks)
 
 _lcs_pos ($ypos)
 
 _compareseq ($xoff, $xlim, $yoff, $ylim)
 
 _shift_boundaries ($lines, &$changed, $other_changed)
 

Detailed Description

Class used internally by Diff to actually compute the diffs.

The algorithm used here is mostly lifted from the perl module Algorithm::Diff (version 1.06) by Ned Konz, which is available at: http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip

More ideas are taken from: http://www.ics.uci.edu/~eppstein/161/960229.html

Some ideas are (and a bit of code) are from from analyze.c, from GNU diffutils-2.7, which can be found at: ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz

closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations) are my own.

Author
Geoffrey T. Dairiki @access private

Definition at line 105 of file DifferenceEngine.php.

Member Function Documentation

◆ _compareseq()

_DiffEngine::_compareseq (   $xoff,
  $xlim,
  $yoff,
  $ylim 
)

Find LCS of two sequences.

The results are recorded in the vectors $this->{x,y}changed[], by storing a 1 in the element for each line that is an insertion or deletion (ie. is not in the LCS).

The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.

Note that XLIM, YLIM are exclusive bounds. All line numbers are origin-0 and discarded lines are not counted.

Definition at line 323 of file DifferenceEngine.php.

References _diag().

Referenced by diff().

◆ _diag()

_DiffEngine::_diag (   $xoff,
  $xlim,
  $yoff,
  $ylim,
  $nchunks 
)

Divide the Largest Common Subsequence (LCS) of the sequences [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally sized segments.

Returns (LCS, PTS). LCS is the length of the LCS. PTS is an array of NCHUNKS+1 (X, Y) indexes giving the diving points between sub sequences. The first sub-sequence is contained in [X0, X1), [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on. Note that (X0, Y0) == (XOFF, YOFF) and (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).

This function assumes that the first lines of the specified portions of the two files do not match, and likewise that the last lines do not match. The caller must trim matching lines from the beginning and end of the portions it is going to specify.

Definition at line 212 of file DifferenceEngine.php.

References _lcs_pos(), and USE_ASSERTS.

Referenced by _compareseq().

◆ _lcs_pos()

_DiffEngine::_lcs_pos (   $ypos)

Definition at line 286 of file DifferenceEngine.php.

References USE_ASSERTS.

Referenced by _diag().

◆ _shift_boundaries()

_DiffEngine::_shift_boundaries (   $lines,
$changed,
  $other_changed 
)

Adjust inserts/deletes of identical lines to join changes as much as possible.

We do something when a run of changed lines include a line at one end and has an excluded, identical line at the other. We are free to choose which identical line is included. ‘compareseq’ usually chooses the one at the beginning, but usually it is cleaner to consider the following identical line to be the "change".

This is extracted verbatim from analyze.c (GNU diffutils-2.7).

Definition at line 381 of file DifferenceEngine.php.

References USE_ASSERTS.

Referenced by diff().

◆ diff()

_DiffEngine::diff (   $from_lines,
  $to_lines 
)

Definition at line 107 of file DifferenceEngine.php.

References _compareseq(), _shift_boundaries(), and USE_ASSERTS.

Referenced by Diff\Diff().


The documentation for this class was generated from the following file: