Merge pull request #1849 from radarhere/frames

Common seek frame position check

PIL/DcxImagePlugin.py

@@ -59,6 +59,7 @@ def _open(self):
             self._offset.append(offset)
 
         self.__fp = self.fp
+        self.frame = None
         self.seek(0)
 
     @property
@@ -70,8 +71,8 @@ def is_animated(self):
         return len(self._offset) > 1
 
     def seek(self, frame):
-        if frame >= len(self._offset):
-            raise EOFError("attempt to seek outside DCX directory")
+        if not self._seek_check(frame):
+            return
         self.frame = frame
         self.fp = self.__fp
         self.fp.seek(self._offset[frame])

PIL/FliImagePlugin.py

@@ -118,12 +118,10 @@ def is_animated(self):
         return self.__framecount > 1
 
     def seek(self, frame):
-        if frame == self.__frame:
+        if not self._seek_check(frame):
             return
         if frame < self.__frame:
             self._seek(0)
-        if frame >= self.__framecount:
-            raise EOFError("no more images in FLI file")
 
         for f in range(self.__frame + 1, frame + 1):
             self._seek(f)

PIL/GifImagePlugin.py

@@ -48,7 +48,7 @@ class GifImageFile(ImageFile.ImageFile):
     format = "GIF"
     format_description = "Compuserve GIF"
     _close_exclusive_fp_after_loading = False
-    
+
     global_palette = None
 
     def data(self):
@@ -117,7 +117,7 @@ def is_animated(self):
         return self._is_animated
 
     def seek(self, frame):
-        if frame == self.__frame:
+        if not self._seek_check(frame):
             return
         if frame < self.__frame:
             self._seek(0)

PIL/ImImagePlugin.py

@@ -270,11 +270,7 @@ def is_animated(self):
         return self.info[FRAMES] > 1
 
     def seek(self, frame):
-
-        if frame < 0 or frame >= self.info[FRAMES]:
-            raise EOFError("seek outside sequence")
-
-        if self.frame == frame:
+        if not self._seek_check(frame):
             return
 
         self.frame = frame
@@ -292,7 +288,6 @@ def seek(self, frame):
         self.tile = [("raw", (0, 0)+self.size, offs, (self.rawmode, 0, -1))]
 
     def tell(self):
-
         return self.frame
 
 #

PIL/ImageFile.py

@@ -78,6 +78,8 @@ class ImageFile(Image.Image):
     def __init__(self, fp=None, filename=None):
         Image.Image.__init__(self)
 
+        self._min_frame = 0
+
         self.tile = None
         self.readonly = 1  # until we know better
 
@@ -275,6 +277,16 @@ def load_end(self):
     # def load_read(self, bytes):
     #     pass
 
+    def _seek_check(self, frame):
+        if (frame < self._min_frame or
+            # Only check upper limit on frames if additional seek operations
+            # are not required to do so
+            (not (hasattr(self, "_n_frames") and self._n_frames is None) and
+             frame >= self.n_frames+self._min_frame)):
+            raise EOFError("attempt to seek outside sequence")
+
+        return self.tell() != frame
+
 
 class StubImageFile(ImageFile):
     """

PIL/MicImagePlugin.py

@@ -65,7 +65,7 @@ def _open(self):
             raise SyntaxError("not an MIC file; no image entries")
 
         self.__fp = self.fp
-        self.frame = 0
+        self.frame = None
 
         if len(self.images) > 1:
             self.category = Image.CONTAINER
@@ -81,7 +81,8 @@ def is_animated(self):
         return len(self.images) > 1
 
     def seek(self, frame):
-
+        if not self._seek_check(frame):
+            return
         try:
             filename = self.images[frame]
         except IndexError:

PIL/MpoImagePlugin.py

@@ -72,14 +72,13 @@ def is_animated(self):
         return self.__framecount > 1
 
     def seek(self, frame):
-        if frame < 0 or frame >= self.__framecount:
-            raise EOFError("no more images in MPO file")
-        else:
-            self.fp = self.__fp
-            self.offset = self.__mpoffsets[frame]
-            self.tile = [
-                ("jpeg", (0, 0) + self.size, self.offset, (self.mode, ""))
-            ]
+        if not self._seek_check(frame):
+            return
+        self.fp = self.__fp
+        self.offset = self.__mpoffsets[frame]
+        self.tile = [
+            ("jpeg", (0, 0) + self.size, self.offset, (self.mode, ""))
+        ]
         self.__frame = frame
 
     def tell(self):

PIL/PsdImagePlugin.py

@@ -124,7 +124,8 @@ def _open(self):
 
         # keep the file open
         self._fp = self.fp
-        self.frame = 0
+        self.frame = 1
+        self._min_frame = 1
 
     @property
     def n_frames(self):
@@ -135,12 +136,11 @@ def is_animated(self):
         return len(self.layers) > 1
 
     def seek(self, layer):
-        # seek to given layer (1..max)
-        if layer == self.frame:
+        if not self._seek_check(layer):
             return
+
+        # seek to given layer (1..max)
         try:
-            if layer <= 0:
-                raise IndexError
             name, mode, bbox, tile = self.layers[layer-1]
             self.mode = mode
             self.tile = tile

PIL/SpiderImagePlugin.py

@@ -174,8 +174,8 @@ def tell(self):
     def seek(self, frame):
         if self.istack == 0:
             raise EOFError("attempt to seek in a non-stack file")
-        if frame >= self._nimages:
-            raise EOFError("attempt to seek past end of file")
+        if not self._seek_check(frame):
+            return
         self.stkoffset = self.hdrlen + frame * (self.hdrlen + self.imgbytes)
         self.fp = self.__fp
         self.fp.seek(self.stkoffset)

PIL/TiffImagePlugin.py

@@ -555,8 +555,8 @@ def _setitem(self, tag, value, legacy_api):
         # Spec'd length == 1, Actual > 1, Warn and truncate. Formerly barfed.
         # No Spec, Actual length 1, Formerly (<4.2) returned a 1 element tuple.
         # Don't mess with the legacy api, since it's frozen.
-        if ((info.length == 1) or 
-            (info.length is None and len(values) == 1 and not legacy_api)): 
+        if ((info.length == 1) or
+            (info.length is None and len(values) == 1 and not legacy_api)):
             # Don't mess with the legacy api, since it's frozen.
             if legacy_api and self.tagtype[tag] in [5, 10]: # rationals
                 values = values,
@@ -980,7 +980,9 @@ def is_animated(self):
 
     def seek(self, frame):
         "Select a given frame as current image"
-        self._seek(max(frame, 0))  # Questionable backwards compatibility.
+        if not self._seek_check(frame):
+            return
+        self._seek(frame)
         # Create a new core image object on second and
         # subsequent frames in the image. Image may be
         # different size/mode.

Tests/test_file_dcx.py

@@ -42,15 +42,14 @@ def test_n_frames(self):
 
     def test_eoferror(self):
         im = Image.open(TEST_FILE)
-
         n_frames = im.n_frames
-        while True:
-            n_frames -= 1
-            try:
-                im.seek(n_frames)
-                break
-            except EOFError:
-                self.assertLess(im.tell(), n_frames)
+
+        # Test seeking past the last frame
+        self.assertRaises(EOFError, im.seek, n_frames)
+        self.assertLess(im.tell(), n_frames)
+
+        # Test that seeking to the last frame does not raise an error
+        im.seek(n_frames-1)
 
     def test_seek_too_far(self):
         # Arrange

Tests/test_file_fli.py

@@ -54,24 +54,14 @@ def test_n_frames(self):
 
     def test_eoferror(self):
         im = Image.open(animated_test_file)
-
         n_frames = im.n_frames
-        while True:
-            n_frames -= 1
-            try:
-                im.seek(n_frames)
-                break
-            except EOFError:
-                self.assertLess(im.tell(), n_frames)
-
-    def test_seek_outside(self):
-        # Test negative seek
-        im = Image.open(static_test_file)
-        im.seek(-1)
-        self.assertEqual(im.tell(), 0)
 
-        # Test seek past end of file
-        self.assertRaises(EOFError, im.seek, 2)
+        # Test seeking past the last frame
+        self.assertRaises(EOFError, im.seek, n_frames)
+        self.assertLess(im.tell(), n_frames)
+
+        # Test that seeking to the last frame does not raise an error
+        im.seek(n_frames-1)
 
     def test_seek_tell(self):
         im = Image.open(animated_test_file)
@@ -91,6 +81,10 @@ def test_seek_tell(self):
         layer_number = im.tell()
         self.assertEqual(layer_number, 2)
 
+        im.seek(1)
+        layer_number = im.tell()
+        self.assertEqual(layer_number, 1)
+
 
 if __name__ == '__main__':
     unittest.main()

Tests/test_file_gif.py

@@ -223,15 +223,14 @@ def test_n_frames(self):
 
     def test_eoferror(self):
         im = Image.open(TEST_GIF)
-
         n_frames = im.n_frames
-        while True:
-            n_frames -= 1
-            try:
-                im.seek(n_frames)
-                break
-            except EOFError:
-                self.assertLess(im.tell(), n_frames)
+
+        # Test seeking past the last frame
+        self.assertRaises(EOFError, im.seek, n_frames)
+        self.assertLess(im.tell(), n_frames)
+
+        # Test that seeking to the last frame does not raise an error
+        im.seek(n_frames-1)
 
     def test_dispose_none(self):
         img = Image.open("Tests/images/dispose_none.gif")

Tests/test_file_im.py

@@ -32,15 +32,14 @@ def test_n_frames(self):
 
     def test_eoferror(self):
         im = Image.open(TEST_IM)
-
         n_frames = im.n_frames
-        while True:
-            n_frames -= 1
-            try:
-                im.seek(n_frames)
-                break
-            except EOFError:
-                self.assertLess(im.tell(), n_frames)
+
+        # Test seeking past the last frame
+        self.assertRaises(EOFError, im.seek, n_frames)
+        self.assertLess(im.tell(), n_frames)
+
+        # Test that seeking to the last frame does not raise an error
+        im.seek(n_frames-1)
 
     def test_roundtrip(self):
         for mode in ["RGB", "P"]:

Tests/test_file_mpo.py

@@ -102,15 +102,14 @@ def test_n_frames(self):
 
     def test_eoferror(self):
         im = Image.open("Tests/images/sugarshack.mpo")
-
         n_frames = im.n_frames
-        while True:
-            n_frames -= 1
-            try:
-                im.seek(n_frames)
-                break
-            except EOFError:
-                self.assertLess(im.tell(), n_frames)
+
+        # Test seeking past the last frame
+        self.assertRaises(EOFError, im.seek, n_frames)
+        self.assertLess(im.tell(), n_frames)
+
+        # Test that seeking to the last frame does not raise an error
+        im.seek(n_frames-1)
 
     def test_image_grab(self):
         for test_file in test_files:

Tests/test_file_psd.py

@@ -34,26 +34,23 @@ def test_n_frames(self):
 
     def test_eoferror(self):
         im = Image.open(test_file)
+        # PSD seek index starts at 1 rather than 0
+        n_frames = im.n_frames+1
 
-        n_frames = im.n_frames
-        while True:
-            n_frames -= 1
-            try:
-                # PSD seek index starts at 1 rather than 0
-                im.seek(n_frames+1)
-                break
-            except EOFError:
-                self.assertLess(im.tell(), n_frames)
+        # Test seeking past the last frame
+        self.assertRaises(EOFError, im.seek, n_frames)
+        self.assertLess(im.tell(), n_frames)
+
+        # Test that seeking to the last frame does not raise an error
+        im.seek(n_frames-1)
 
     def test_seek_tell(self):
         im = Image.open(test_file)
 
         layer_number = im.tell()
-        self.assertEqual(layer_number, 0)
+        self.assertEqual(layer_number, 1)
 
-        im.seek(0)
-        layer_number = im.tell()
-        self.assertEqual(layer_number, 0)
+        self.assertRaises(EOFError, im.seek, 0)
 
         im.seek(1)
         layer_number = im.tell()