[meld] Refactor change_sequence

[Kai Willadsen <kaiw src gnome org>]

commit 6caa1317c21b39ba00c8338159d088b754d17cdd
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Tue Jun 2 15:39:11 2009 +1000

    Refactor change_sequence
    
    Differ only has two internal diffs that need to be updated on sequence
    change. The updating logic can be simplified by enumerating conditions
    for each sequence.

 diffutil.py |   11 ++++-------
 1 files changed, 4 insertions(+), 7 deletions(-)
---
diff --git a/diffutil.py b/diffutil.py
index 6314659..43cdc4f 100644
--- a/diffutil.py
+++ b/diffutil.py
@@ -68,14 +68,11 @@ class Differ(object):
         self.diffs = [[], []]
 
     def change_sequence(self, sequence, startidx, sizechange, texts):
-        assert sequence in (0,1,2)
-        if sequence != 1: #0 or 2
-            which = sequence / 2
-            self._change_sequence(which, sequence, startidx, sizechange, texts)
-        else: # sequence==1:
+        assert sequence in (0, 1, 2)
+        if sequence == 0 or sequence == 1:
             self._change_sequence(0, sequence, startidx, sizechange, texts)
-            if self.num_sequences == 3:
-                self._change_sequence(1, sequence, startidx, sizechange, texts)
+        if sequence == 2 or (sequence == 1 and self.num_sequences == 3):
+            self._change_sequence(1, sequence, startidx, sizechange, texts)
         self.seqlength[sequence] += sizechange
 
     def _locate_chunk(self, whichdiffs, sequence, line):