#3424 rearrange the order of tests in imghdr to place more common types first

Lib/imghdr.py

@@ -34,12 +34,25 @@ def what(file, h=None):
 
 tests = []
 
-def test_rgb(h, f):
-    """SGI image library"""
-    if h[:2] == '\001\332':
-        return 'rgb'
+def test_jpeg(h, f):
+    """JPEG data in JFIF format"""
+    if h[6:10] == 'JFIF':
+        return 'jpeg'
 
-tests.append(test_rgb)
+tests.append(test_jpeg)
+
+def test_exif(h, f):
+    """JPEG data in Exif format"""
+    if h[6:10] == 'Exif':
+        return 'jpeg'
+
+tests.append(test_exif)
+
+def test_png(h, f):
+    if h[:8] == "\211PNG\r\n\032\n":
+        return 'png'
+
+tests.append(test_png)
 
 def test_gif(h, f):
     """GIF ('87 and '89 variants)"""
@@ -48,6 +61,20 @@ def test_gif(h, f):
 
 tests.append(test_gif)
 
+def test_tiff(h, f):
+    """TIFF (can be in Motorola or Intel byte order)"""
+    if h[:2] in ('MM', 'II'):
+        return 'tiff'
+
+tests.append(test_tiff)
+
+def test_rgb(h, f):
+    """SGI image library"""
+    if h[:2] == '\001\332':
+        return 'rgb'
+
+tests.append(test_rgb)
+
 def test_pbm(h, f):
     """PBM (portable bitmap)"""
     if len(h) >= 3 and \
@@ -72,13 +99,6 @@ def test_ppm(h, f):
 
 tests.append(test_ppm)
 
-def test_tiff(h, f):
-    """TIFF (can be in Motorola or Intel byte order)"""
-    if h[:2] in ('MM', 'II'):
-        return 'tiff'
-
-tests.append(test_tiff)
-
 def test_rast(h, f):
     """Sun raster file"""
     if h[:4] == '\x59\xA6\x6A\x95':
@@ -94,32 +114,12 @@ def test_xbm(h, f):
 
 tests.append(test_xbm)
 
-def test_jpeg(h, f):
-    """JPEG data in JFIF format"""
-    if h[6:10] == 'JFIF':
-        return 'jpeg'
-
-tests.append(test_jpeg)
-
-def test_exif(h, f):
-    """JPEG data in Exif format"""
-    if h[6:10] == 'Exif':
-        return 'jpeg'
-
-tests.append(test_exif)
-
 def test_bmp(h, f):
     if h[:2] == 'BM':
         return 'bmp'
 
 tests.append(test_bmp)
 
-def test_png(h, f):
-    if h[:8] == "\211PNG\r\n\032\n":
-        return 'png'
-
-tests.append(test_png)
-
 #--------------------#
 # Small test program #
 #--------------------#