Merge pull request julien-duponchelle#49 from alex/fix-int24

bjoernhaeuser · bjoernhaeuser · commit 401ea6c9766a · 2013-08-25T12:29:51.000-07:00
Fixed parsing of small int24 values
diff --git a/pymysqlreplication/packet.py b/pymysqlreplication/packet.py
@@ -206,17 +206,17 @@ def read_length_coded_pascal_string(self, size):
 
     def read_int24(self):
         a, b, c = struct.unpack("BBB", self.read(3))
-        if a & 128:
-            return a + (b << 8) + (c << 16)
-        else:
-            return (a + (b << 8) + (c << 16)) * -1
+        res = a | (b << 8) | (c << 16)
+        if res >= 0x800000:
+            res -= 0x1000000
+        return res
 
     def read_int24_be(self):
         a, b, c = struct.unpack('BBB', self.read(3))
-        if a & 128 == 0:
-            return (a << 16) | (b << 8) | c
-        else:
-            return (-1 << 24) | (a << 16) | (b << 8) | c
+        res = (a << 16) | (b << 8) | c
+        if res >= 0x800000:
+            res -= 0x1000000
+        return res
 
     def read_uint8(self):
         return struct.unpack('<B', self.read(1))[0]
diff --git a/pymysqlreplication/tests/test_data_type.py b/pymysqlreplication/tests/test_data_type.py
@@ -222,12 +222,15 @@ def test_longlong(self):
         self.assertEqual(event.rows[0]["values"]["test"], -9223372036854775808)
 
     def test_int24(self):
-        create_query = "CREATE TABLE test (id MEDIUMINT UNSIGNED NOT NULL, test MEDIUMINT, test2 MEDIUMINT)"
-        insert_query = "INSERT INTO test VALUES(16777215, 8388607, -8388608)"
+        create_query = "CREATE TABLE test (id MEDIUMINT UNSIGNED NOT NULL, test MEDIUMINT, test2 MEDIUMINT, test3 MEDIUMINT, test4 MEDIUMINT, test5 MEDIUMINT)"
+        insert_query = "INSERT INTO test VALUES(16777215, 8388607, -8388608, 8, -8, 0)"
         event = self.create_and_insert_value(create_query, insert_query)
         self.assertEqual(event.rows[0]["values"]["id"], 16777215)
         self.assertEqual(event.rows[0]["values"]["test"], 8388607)
         self.assertEqual(event.rows[0]["values"]["test2"], -8388608)
+        self.assertEqual(event.rows[0]["values"]["test3"], 8)
+        self.assertEqual(event.rows[0]["values"]["test4"], -8)
+        self.assertEqual(event.rows[0]["values"]["test5"], 0)
 
     def test_date(self):
         create_query = "CREATE TABLE test (test DATE);"
