Revert changes from PR python-pillow#1121, for python-pillow#1163

PIL/_binary.py

@@ -11,8 +11,6 @@
 # See the README file for information on usage and redistribution.
 #
 
-from struct import unpack, pack
-
 if bytes is str:
     def i8(c):
         return ord(c)
@@ -36,7 +34,7 @@ def i16le(c, o=0):
     c: string containing bytes to convert
     o: offset of bytes to convert in string
     """
-    return unpack("<H", c[o:o+2])
+    return i8(c[o]) | (i8(c[o+1]) << 8)
 
 
 def i32le(c, o=0):
@@ -46,31 +44,33 @@ def i32le(c, o=0):
     c: string containing bytes to convert
     o: offset of bytes to convert in string
     """
-    return unpack("<I", c[o:o+4])
+    return (i8(c[o]) | (i8(c[o+1]) << 8) | (i8(c[o+2]) << 16) |
+            (i8(c[o+3]) << 24))
 
 
 def i16be(c, o=0):
-    return unpack(">H", c[o:o+2])
+    return (i8(c[o]) << 8) | i8(c[o+1])
 
 
 def i32be(c, o=0):
-    return unpack(">I", c[o:o+4])
+    return ((i8(c[o]) << 24) | (i8(c[o+1]) << 16) |
+            (i8(c[o+2]) << 8) | i8(c[o+3]))
 
 
 # Output, le = little endian, be = big endian
 def o16le(i):
-    return pack("<H", i)
+    return o8(i) + o8(i >> 8)
 
 
 def o32le(i):
-    return pack("<I", i)
+    return o8(i) + o8(i >> 8) + o8(i >> 16) + o8(i >> 24)
 
 
 def o16be(i):
-    return pack(">H", i)
+    return o8(i >> 8) + o8(i)
 
 
 def o32be(i):
-    return pack(">I", i)
+    return o8(i >> 24) + o8(i >> 16) + o8(i >> 8) + o8(i)
 
 # End of file