Performance up.

doc/changes.rst

@@ -1,6 +1,12 @@
 Changelog
 =========
 
+
+1.0.9
+-----
+
+- Performance up "load" jpeg from file.
+
 1.0.8
 -----
 

piexif/__init__.py

@@ -6,4 +6,4 @@
 from ._exif import *
 
 
-VERSION = '1.0.8'
+VERSION = '1.0.9'

piexif/_common.py

@@ -24,6 +24,34 @@ def split_into_segments(data):
             raise ValueError("Wrong JPEG data.")
     return segments
 
+def read_exif_from_file(filename):
+    """Slices JPEG meta data into a list from JPEG binary data.
+    """
+    f = open(filename, "rb")
+    data = f.read(6)
+
+    if data[0:2] != b"\xff\xd8":
+        raise ValueError("Given data isn't JPEG.")
+
+    head = data[2:6]
+    head_pos = 2
+    HEAD_LENGTH = 4
+    exif = None
+    while 1:
+        length = struct.unpack(">H", head[2: 4])[0]
+
+        if head[:2] == b"\xff\xe1":
+            segment_data = f.read(length - 2)
+            exif = head + segment_data
+            break
+        elif head[0:1] == b"\xff":
+            f.read(length - 2)
+            head = f.read(HEAD_LENGTH)
+        else:
+            break
+
+    f.close()
+    return exif
 
 def get_exif_seg(segments):
     """Returns Exif from JPEG meta data list

piexif/_load.py

@@ -74,18 +74,18 @@ def __init__(self, data):
         else:
             try:
                 with open(data, 'rb') as f:
-                    data = f.read()
+                    magic_number = f.read(2)
             except:
                 raise ValueError("Got invalid value.")
-            if data[0:2] == b"\xff\xd8":  # JPEG
-                segments = split_into_segments(data)
-                app1 = get_exif_seg(segments)
+            if magic_number == b"\xff\xd8":  # JPEG
+                app1 = read_exif_from_file(data)
                 if app1:
                     self.tiftag = app1[10:]
                 else:
                     self.tiftag = None
-            elif data[0:2] in (b"\x49\x49", b"\x4d4d"):  # TIFF
-                self.tiftag = data
+            elif magic_number in (b"\x49\x49", b"\x4d4d"):  # TIFF
+                with open(data, 'rb') as f:
+                    self.tiftag = f.read()
             else:
                 raise ValueError("Given file is neither JPEG nor TIFF.")