[meld] Add SyncPointMyersSequenceMatcher and matcher-related unit tests

[Kai Willadsen <kaiw src gnome org>]

commit 6596491cb6c73fdc4d05afda740d870c978bf209
Author: Piotr Piastucki <the_leech users berlios de>
Date:   Tue Mar 19 23:28:06 2013 +0100

    Add SyncPointMyersSequenceMatcher and matcher-related unit tests

 meld/matchers.py      |   40 +++++++++++++++++++++++++++++
 meld/test_matchers.py |   66 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 106 insertions(+), 0 deletions(-)
---
diff --git a/meld/matchers.py b/meld/matchers.py
index 27b41cc..cf103b7 100644
--- a/meld/matchers.py
+++ b/meld/matchers.py
@@ -359,3 +359,43 @@ class InlineMyersSequenceMatcher(MyersSequenceMatcher):
             a = indexed_a
             b = indexed_b
         return (a, b)
+        
+class SyncPointMyersSequenceMatcher(MyersSequenceMatcher):
+
+    def __init__(self, isjunk=None, a="", b="", syncpoints=None):
+        MyersSequenceMatcher.__init__(self, isjunk, a, b)
+        self.isjunk = isjunk
+        self.syncpoints = syncpoints
+        
+    def initialise(self):
+        if self.syncpoints is None or len(self.syncpoints) == 0:
+            for i in MyersSequenceMatcher.initialise(self):
+                yield i
+        else:
+            chunks = []
+            ai = 0
+            bi = 0
+            for aj, bj in self.syncpoints:
+                chunks.append((ai, bi, self.a[ai:aj], self.b[bi:bj]))
+                ai = aj
+                bi = bj
+            if ai < len(self.a) or bi < len(self.b):
+                chunks.append((ai, bi, self.a[ai:len(self.a)], self.b[bi:len(self.b)]))
+            self.matching_blocks = []
+            for ai, bi, a, b in chunks:
+                matcher = MyersSequenceMatcher(self.isjunk, a, b)
+                for i in matcher.initialise():
+                    yield i
+                blocks = matcher.get_matching_blocks()
+                l = len(self.matching_blocks) - 1
+                if l >= 0 and len(blocks) > 1:
+                    aj = self.matching_blocks[l][0]  
+                    bj = self.matching_blocks[l][1]
+                    bl = self.matching_blocks[l][2]
+                    if aj + bl == ai and bj + bl == bi and blocks[0][0] == 0 and blocks[0][1] == 0:
+                        block = blocks.pop(0)
+                        self.matching_blocks[l] = (aj, bj, bl + block[2])
+                for x, y, l in blocks[:-1]:
+                    self.matching_blocks.append((ai + x, bi + y, l))
+            self.matching_blocks.append((len(self.a), len(self.b), 0))
+        
diff --git a/meld/test_matchers.py b/meld/test_matchers.py
new file mode 100644
index 0000000..9cb7069
--- /dev/null
+++ b/meld/test_matchers.py
@@ -0,0 +1,66 @@
+
+import unittest
+import matchers
+
+class MatchersTests(unittest.TestCase):
+
+    def testBasicMatcher(self):
+        a = list('abcbdefgabcdefg')
+        b = list('gfabcdefcd')
+        r = [(0, 2, 3), (4, 5, 3), (10, 8, 2), (15, 10, 0)]
+        matcher = matchers.MyersSequenceMatcher(None, a, b)
+        blocks = matcher.get_matching_blocks()
+        self.assertEqual(len(blocks), len(r))
+        for i in range(len(blocks)):
+            self.assertEqual(blocks[i], r[i])
+
+    def testPostprocessingCleanup(self):
+        a = list('abcfabgcd')
+        b = list('afabcgabgcabcd')
+        r = [(0, 2, 3), (4, 6, 3), (7, 12, 2), (9, 14, 0)]
+        matcher = matchers.MyersSequenceMatcher(None, a, b)
+        blocks = matcher.get_matching_blocks()
+        self.assertEqual(len(blocks), len(r))
+        for i in range(len(blocks)):
+            self.assertEqual(blocks[i], r[i])
+
+    def testInlineMatcher(self):
+        a = 'red, blue, yellow, white'
+        b = 'black green, hue, white'
+        r = [(17, 16, 7), (24, 23, 0)]
+        matcher = matchers.InlineMyersSequenceMatcher(None, a, b)
+        blocks = matcher.get_matching_blocks()
+        self.assertEqual(len(blocks), len(r))
+        for i in range(len(blocks)):
+            self.assertEqual(blocks[i], r[i])
+
+    def testSyncPointMatcher0(self):
+        a = list('012a3456c789')
+        b = list('0a3412b5678')
+        r = [(0, 0, 1), (3, 1, 3), (6, 7, 2), (9, 9, 2), (12, 11, 0)]
+        matcher = matchers.SyncPointMyersSequenceMatcher(None, a, b)
+        blocks = matcher.get_matching_blocks()
+        self.assertEqual(len(blocks), len(r))
+        for i in range(len(blocks)):
+            self.assertEqual(blocks[i], r[i])
+
+    def testSyncPointMatcher1(self):
+        a = list('012a3456c789')
+        b = list('0a3412b5678')
+        r = [(0, 0, 1), (1, 4, 2), (6, 7, 2), (9, 9, 2), (12, 11, 0)]
+        matcher = matchers.SyncPointMyersSequenceMatcher(None, a, b, [(3,6)])
+        blocks = matcher.get_matching_blocks()
+        self.assertEqual(len(blocks), len(r))
+        for i in range(len(blocks)):
+            self.assertEqual(blocks[i], r[i])
+
+    def testSyncPointMatcher2(self):
+        a = list('012a3456c789')
+        b = list('02a341b5678')
+        r = [(0, 0, 1), (2, 1, 4), (9, 9, 2), (12, 11, 0)]
+        matcher = matchers.SyncPointMyersSequenceMatcher(None, a, b, [(3,2), (8,6)])
+        blocks = matcher.get_matching_blocks()
+        self.assertEqual(len(blocks), len(r))
+        self.assertEqual(blocks[0], r[0])
+        self.assertEqual(blocks[1], r[1])
+        
\ No newline at end of file