Text_Diff Class Reference

Inheritance diagram for Text_Diff:

Collaboration diagram for Text_Diff:

Public Member Functions
	__construct ($from_lines, $to_lines)
	Computes diffs between sequences of strings. More...
	getDiff ()
	Returns the array of differences. More...
	reverse ()
	Computes a reversed diff. More...
	isEmpty ()
	Checks for an empty diff. More...
	lcs ()
	Computes the length of the Longest Common Subsequence (LCS). More...
	getOriginal ()
	Gets the original set of lines. More...
	getFinal ()
	Gets the final set of lines. More...
	_trimNewlines (&$line, $key)
	Removes trailing newlines from a line of text. More...
	_check ($from_lines, $to_lines)
	Checks a diff for validity. More...

Data Fields
	$_edits

Detailed Description

Definition at line 16 of file Diff.php.

Constructor & Destructor Documentation

__construct()

Text_Diff::__construct	(		$from_lines,
			$to_lines
	)

Computes diffs between sequences of strings.

Parameters

array	$from_lines	An array of strings. Typically these are lines from a file.
array	$to_lines	An array of strings.

Definition at line 33 of file Diff.php.

    {
        array_walk($from_lines, array($this, '_trimNewlines'));
        array_walk($to_lines, array($this, '_trimNewlines'));
 
        if (extension_loaded('xdiff')) {
            $engine = new Text_Diff_Engine_xdiff();
        } else {
            $engine = new Text_Diff_Engine_native();
        }
 
        $this->_edits = $engine->diff($from_lines, $to_lines);
    }

References $engine.

Member Function Documentation

_check()

Text_Diff::_check	(		$from_lines,
			$to_lines
	)

Checks a diff for validity.

This is here only for debugging purposes.

Definition at line 166 of file Diff.php.

    {
        if (serialize($from_lines) != serialize($this->getOriginal())) {
            trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
        }
        if (serialize($to_lines) != serialize($this->getFinal())) {
            trigger_error("Reconstructed final doesn't match", E_USER_ERROR);
        }
 
        $rev = $this->reverse();
        if (serialize($to_lines) != serialize($rev->getOriginal())) {
            trigger_error("Reversed original doesn't match", E_USER_ERROR);
        }
        if (serialize($from_lines) != serialize($rev->getFinal())) {
            trigger_error("Reversed final doesn't match", E_USER_ERROR);
        }
 
        $prevtype = null;
        foreach ($this->_edits as $edit) {
            if ($prevtype == get_class($edit)) {
                trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
            }
            $prevtype = get_class($edit);
        }
 
        return true;
    }

References getFinal(), getOriginal(), and reverse().

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_trimNewlines()

Text_Diff::_trimNewlines	(	&	$line,
			$key
	)

Removes trailing newlines from a line of text.

This is meant to be used with array_walk().

Parameters

string	$line	The line to trim.
integer	$key	The index of the line in the array. Not used.

Definition at line 156 of file Diff.php.

    {
        $line = str_replace(array("\n", "\r"), '', $line);
    }

getDiff()

Text_Diff::getDiff

(

)

Returns the array of differences.

Definition at line 50 of file Diff.php.

    {
        return $this->_edits;
    }

References $_edits.

getFinal()

Text_Diff::getFinal

(

)

Gets the final set of lines.

This reconstructs the $to_lines parameter passed to the constructor.

Returns

array The sequence of strings.

Definition at line 138 of file Diff.php.

    {
        $lines = array();
        foreach ($this->_edits as $edit) {
            if ($edit->final) {
                array_splice($lines, count($lines), 0, $edit->final);
            }
        }
        return $lines;
    }

Referenced by _check().

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getOriginal()

Text_Diff::getOriginal

(

)

Gets the original set of lines.

This reconstructs the $from_lines parameter passed to the constructor.

Returns

array The original sequence of strings.

Definition at line 120 of file Diff.php.

    {
        $lines = array();
        foreach ($this->_edits as $edit) {
            if ($edit->orig) {
                array_splice($lines, count($lines), 0, $edit->orig);
            }
        }
        return $lines;
    }

Referenced by _check().

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isEmpty()

Text_Diff::isEmpty

(

)

Checks for an empty diff.

Returns

boolean True if two sequences were identical.

Definition at line 85 of file Diff.php.

    {
        foreach ($this->_edits as $edit) {
            if (!$edit instanceof Text_Diff_Op_copy) {
                return false;
            }
        }
        return true;
    }

lcs()

Text_Diff::lcs

(

)

Computes the length of the Longest Common Subsequence (LCS).

This is mostly for diagnostic purposes.

Returns

integer The length of the LCS.

Definition at line 102 of file Diff.php.

    {
        $lcs = 0;
        foreach ($this->_edits as $edit) {
            if ($edit instanceof Text_Diff_Op_copy) {
                $lcs += count($edit->orig);
            }
        }
        return $lcs;
    }

reverse()

Text_Diff::reverse

(

)

Computes a reversed diff.

Example: $diff = &new Text_Diff($lines1, $lines2); $rev = $diff->reverse();

Returns

Text_Diff A Diff object representing the inverse of the original diff. Note that we purposely don't return a reference here, since this essentially is a clone() method.

Definition at line 69 of file Diff.php.

    {
        $rev = clone($obj);
 
        $rev->_edits = array();
        foreach ($this->_edits as $edit) {
            $rev->_edits[] = $edit->reverse();
        }
        return $rev;
    }

Referenced by _check().

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Field Documentation

$_edits

Text_Diff::$_edits

Definition at line 24 of file Diff.php.

Referenced by getDiff().

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

• Services/XHTMLValidator/validator/Text_Diff/Diff.php