Fixed diff computation algorithm (it was giving incorrect values).

similarity/diff.class.php

@@ -432,6 +432,7 @@ class vpl_diff {
             while ($i1 < $n1 && $i2 < $n2 && $line1{$i1} == $line2{$i2}) {
                 $i1++;
                 $i2++;
+                $done[$i1][$i2] = true;
             }
 
             if ($i1 == $n1 && $i2 == $n2) {
@@ -440,7 +441,7 @@ class vpl_diff {
             }
 
             // Character addition in line1.
-            if ($i1 < $n1) {
+            if ($i1 < $n1 && !isset($done[$i1 + 1][$i2])) {
                 $z1 = new stdClass();
                 $z1->i1 = $i1 + 1;
                 $z1->i2 = $i2;
@@ -449,7 +450,7 @@ class vpl_diff {
             }
 
             // Character addition in line2.
-            if ($i2 < $n2) {
+            if ($i2 < $n2 && !isset($done[$i1][$i2 + 1])) {
                 $z2 = new stdClass();
                 $z2->i1 = $i1;
                 $z2->i2 = $i2 + 1;
@@ -458,7 +459,7 @@ class vpl_diff {
             }
 
             // Character change.
-            if ($i1 < $n1 && $i2 < $n2) {
+            if ($i1 < $n1 && $i2 < $n2 && !isset($done[$i1 + 1][$i2 + 1])) {
                 $z3 = new stdClass();
                 $z3->i1 = $i1 + 1;
                 $z3->i2 = $i2 + 1;
@@ -497,7 +498,7 @@ class vpl_diff {
 
         // A-star search of shortest diff.
         while (true) {
-            if ($timelimit > 0 && microtime(true)-$starttime > $timelimit/1000) {
+            if ($timelimit > 0 && microtime(true) - $starttime > $timelimit / 1000) {
                 // Time out.
                 throw new Exception();
             }
@@ -517,6 +518,7 @@ class vpl_diff {
             while ($i1 < $n1 && $i2 < $n2 && $lines1[$i1] == $lines2[$i2]) {
                 $i1++;
                 $i2++;
+                $prev[$i1][$i2] = 0;
             }
 
             if ($i1 == $n1 && $i2 == $n2) {
@@ -530,11 +532,11 @@ class vpl_diff {
                     } else {
                         switch ($prev[$i1][$i2]) {
                             case 1 :
-                                $totaldiff += strlen( $lines1[$i1-1] ) + 1;
+                                $totaldiff += strlen( $lines1[$i1 - 1] ) + 1;
                                 $i1--;
                                 break;
                             case 2 :
-                                $totaldiff += strlen( $lines2[$i2-1] ) + 1;
+                                $totaldiff += strlen( $lines2[$i2 - 1] ) + 1;
                                 $i2--;
                                 break;
                             case 3 :
@@ -550,7 +552,7 @@ class vpl_diff {
             }
 
             // Line addition in file1.
-            if ($i1 < $n1) {
+            if ($i1 < $n1 && !isset($prev[$i1 + 1][$i2])) {
                 $z1 = new stdClass();
                 $z1->i1 = $i1 + 1;
                 $z1->i2 = $i2;
@@ -560,7 +562,7 @@ class vpl_diff {
             }
 
             // Line addition in file2.
-            if ($i2 < $n2) {
+            if ($i2 < $n2 && !isset($prev[$i1][$i2 + 1])) {
                 $z2 = new stdClass();
                 $z2->i1 = $i1;
                 $z2->i2 = $i2 + 1;
@@ -570,7 +572,7 @@ class vpl_diff {
             }
 
             // Line change.
-            if ($i1 < $n1 && $i2 < $n2) {
+            if ($i1 < $n1 && $i2 < $n2 && !isset($prev[$i1 + 1][$i2 + 1])) {
                 $z3 = new stdClass();
                 $z3->i1 = $i1 + 1;
                 $z3->i2 = $i2 + 1;
@@ -580,4 +582,4 @@ class vpl_diff {
             }
         }
     }
-}
+}
\ No newline at end of file