class Text_Diff_Renderer {
/**
* Number of leading context "lines" to preserve.
*
* This should be left at zero for this class, but subclasses may want to
* set this to other values.
*/
var $_leading_context_lines = 0;
/**
* Number of trailing context "lines" to preserve.
*
* This should be left at zero for this class, but subclasses may want to
* set this to other values.
*/
var $_trailing_context_lines = 0;
/**
* Constructor.
*/
function __construct( $params = array() )
{
foreach ($params as $param => $value) {
$v = '_' . $param;
if (isset($this->$v)) {
$this->$v = $value;
}
}
}
/**
* PHP4 constructor.
*/
public function Text_Diff_Renderer( $params = array() ) {
self::__construct( $params );
}
/**
* Get any renderer parameters.
*
* @return array All parameters of this renderer object.
*/
function getParams()
{
$params = array();
foreach (get_object_vars($this) as $k => $v) {
if ($k[0] == '_') {
$params[substr($k, 1)] = $v;
}
}
return $params;
}
/**
* Renders a diff.
*
* @param Text_Diff $diff A Text_Diff object.
*
* @return string The formatted output.
*/
function render($diff)
{
$xi = $yi = 1;
$block = false;
$context = array();
$nlead = $this->_leading_context_lines;
$ntrail = $this->_trailing_context_lines;
$output = $this->_startDiff();
$diffs = $diff->getDiff();
foreach ($diffs as $i => $edit) {
/* If these are unchanged (copied) lines, and we want to keep
* leading or trailing context lines, extract them from the copy
* block. */
if (is_a($edit, 'Text_Diff_Op_copy')) {
/* Do we have any diff blocks yet? */
if (is_array($block)) {
/* How many lines to keep as context from the copy
* block. */
$keep = $i == count($diffs) - 1 ? $ntrail : $nlead + $ntrail;
if (count($edit->orig) <= $keep) {
/* We have less lines in the block than we want for
* context => keep the whole block. */
$block[] = $edit;
} else {
if ($ntrail) {
/* Create a new block with as many lines as we need
* for the trailing context. */
$context = array_slice($edit->orig, 0, $ntrail);
$block[] = new Text_Diff_Op_copy($context);
}
/* @todo */
$output .= $this->_block($x0, $ntrail + $xi - $x0,
$y0, $ntrail + $yi - $y0,
$block);
$block = false;
}
}
/* Keep the copy block as the context for the next block. */
$context = $edit->orig;
} else {
/* Don't we have any diff blocks yet? */
if (!is_array($block)) {
/* Extract context lines from the preceding copy block. */
$context = array_slice($context, count($context) - $nlead);
$x0 = $xi - count($context);
$y0 = $yi - count($context);
$block = array();
if ($context) {
$block[] = new Text_Diff_Op_copy($context);
}
}
$block[] = $edit;
}
if ($edit->orig) {
$xi += count($edit->orig);
}
if ($edit->final) {
$yi += count($edit->final);
}
}
if (is_array($block)) {
$output .= $this->_block($x0, $xi - $x0,
$y0, $yi - $y0,
$block);
}
return $output . $this->_endDiff();
}
function _block($xbeg, $xlen, $ybeg, $ylen, &$edits)
{
$output = $this->_startBlock($this->_blockHeader($xbeg, $xlen, $ybeg, $ylen));
foreach ($edits as $edit) {
switch (strtolower(get_class($edit))) {
case 'text_diff_op_copy':
$output .= $this->_context($edit->orig);
break;
case 'text_diff_op_add':
$output .= $this->_added($edit->final);
break;
case 'text_diff_op_delete':
$output .= $this->_deleted($edit->orig);
break;
case 'text_diff_op_change':
$output .= $this->_changed($edit->orig, $edit->final);
break;
}
}
return $output . $this->_endBlock();
}
function _startDiff()
{
return '';
}
function _endDiff()
{
return '';
}
function _blockHeader($xbeg, $xlen, $ybeg, $ylen)
{
if ($xlen > 1) {
$xbeg .= ',' . ($xbeg + $xlen - 1);
}
if ($ylen > 1) {
$ybeg .= ',' . ($ybeg + $ylen - 1);
}
// this matches the GNU Diff behaviour
if ($xlen && !$ylen) {
$ybeg--;
} elseif (!$xlen) {
$xbeg--;
}
return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
}
function _startBlock($header)
{
return $header . "\n";
}
function _endBlock()
{
return '';
}
function _lines($lines, $prefix = ' ')
{
return $prefix . implode("\n$prefix", $lines) . "\n";
}
function _context($lines)
{
return $this->_lines($lines, ' ');
}
function _added($lines)
{
return $this->_lines($lines, '> ');
}
function _deleted($lines)
{
return $this->_lines($lines, '< ');
}
function _changed($orig, $final)
{
return $this->_deleted($orig) . "---\n" . $this->_added($final);
}
}
