2016 Update

Task/Bitwise-IO/Python/bitwise-io-1.py

@@ -1,4 +1,4 @@
-class BitWriter:
+class BitWriter(object):
     def __init__(self, f):
         self.accumulator = 0
         self.bcount = 0
@@ -7,48 +7,71 @@ class BitWriter:
     def __del__(self):
         try:
             self.flush()
-        except ValueError:  # I/O operation on closed file
+        except ValueError:   # I/O operation on closed file
             pass
 
-    def writebit(self, bit):
-        if self.bcount == 8 :
+    def _writebit(self, bit):
+        if self.bcount == 8:
             self.flush()
         if bit > 0:
-            self.accumulator |= (1 << (7-self.bcount))
+            self.accumulator |= 1 << 7-self.bcount
         self.bcount += 1
 
     def writebits(self, bits, n):
         while n > 0:
-            self.writebit( bits & (1 << (n-1)) )
+            self._writebit(bits & 1 << n-1)
             n -= 1
 
     def flush(self):
-        self.out.write(chr(self.accumulator))
+        self.out.write(bytearray([self.accumulator]))
         self.accumulator = 0
         self.bcount = 0
 
 
-class BitReader:
+class BitReader(object):
     def __init__(self, f):
         self.input = f
         self.accumulator = 0
         self.bcount = 0
         self.read = 0
 
-    def readbit(self):
-        if self.bcount == 0 :
+    def _readbit(self):
+        if not self.bcount:
             a = self.input.read(1)
-            if ( len(a) > 0 ):
+            if a:
                 self.accumulator = ord(a)
             self.bcount = 8
             self.read = len(a)
-        rv = ( self.accumulator & ( 1 << (self.bcount-1) ) ) >> (self.bcount-1)
+        rv = (self.accumulator & (1 << self.bcount-1)) >> self.bcount-1
         self.bcount -= 1
         return rv
 
     def readbits(self, n):
         v = 0
         while n > 0:
-            v = (v << 1) | self.readbit()
+            v = (v << 1) | self._readbit()
             n -= 1
         return v
+
+if __name__ == '__main__':
+    import os
+    import sys
+    # determine module name from this file's name and import it
+    module_name = os.path.splitext(os.path.basename(__file__))[0]
+    bitio = __import__(module_name)
+
+    with open('bitio_test.dat', 'wb') as outfile:
+        writer = bitio.BitWriter(outfile)
+        chars = '12345abcde'
+        for ch in chars:
+            writer.writebits(ord(ch), 7)
+
+    with open('bitio_test.dat', 'rb') as infile:
+        reader = bitio.BitReader(infile)
+        chars = []
+        while True:
+            x = reader.readbits(7)
+            if reader.read == 0:
+                break
+            chars.append(chr(x))
+        print(''.join(chars))

Task/Bitwise-IO/Python/bitwise-io-2.py

@@ -1,4 +1,3 @@
-#! /usr/bin/env python
 import sys
 import bitio
 

Task/Bitwise-IO/Python/bitwise-io-3.py

@@ -1,10 +1,9 @@
-#! /usr/bin/env python
 import sys
 import bitio
 
 r = bitio.BitReader(sys.stdin)
 while True:
     x = r.readbits(7)
-    if ( r.read == 0 ):
+    if not r.read:  # nothing read
         break
     sys.stdout.write(chr(x))