framing: remove bitarray dependancy

README.md

@@ -38,14 +38,14 @@ on each 250 byte data frame.
 
 # Installation
 
-Make sure that `numpy`, `bitarray` and `PyAudio` Python packages are installed.
+Make sure that `numpy` and `PyAudio` Python packages are installed.
 
-    $ pip install numpy bitarray
-    $ pip install git+http://people.csail.mit.edu/hubert/git/pyaudio.git  # requires portaudio19-dev package
+    $ pip install numpy
+    $ pip install git+http://people.csail.mit.edu/hubert/git/pyaudio.git
 
 or, on Debian/Ubuntu:
 
-    $ sudo apt-get install python-numpy python-bitarray python-pyaudio
+    $ sudo apt-get install python-numpy python-pyaudio
 
 Clone and install latest version:
 

amodem/framing.py

@@ -1,5 +1,4 @@
 from . import common
-import bitarray
 
 import functools
 import itertools
@@ -41,7 +40,7 @@ class Framer(object):
 
     def _pack(self, block):
         frame = self.checksum.encode(block)
-        return struct.pack(self.prefix_fmt, len(frame)) + frame
+        return bytearray(struct.pack(self.prefix_fmt, len(frame)) + frame)
 
     def encode(self, data):
         for block in common.iterate(data=data, size=self.block_size,
@@ -82,21 +81,33 @@ def chain_wrapper(func):
         return itertools.chain.from_iterable(result)
     return wrapped
 
+class BitPacker(object):
+    word_size = 8
+    def __init__(self):
+        bits_list = []
+        for index in range(2 ** self.word_size):
+            bits = [index & (2 ** k) for k in range(self.word_size)]
+            bits_list.append(tuple((1 if b else 0) for b in bits))
+
+        self.to_bits = dict((i, bits) for i, bits in enumerate(bits_list))
+        self.to_byte = dict((bits, i) for i, bits in enumerate(bits_list))
+
 
 @chain_wrapper
 def encode(data, framer=None):
+    converter = BitPacker()
     framer = framer or Framer()
     for frame in framer.encode(data):
-        bits = bitarray.bitarray(endian='little')
-        bits.frombytes(bytes(frame))
-        yield bits
+        for byte in frame:
+            yield converter.to_bits[byte]
 
 
 @chain_wrapper
-def _to_bytes(bits, block_size=1):
-    for chunk in common.iterate(data=bits, size=8*block_size,
-                                func=lambda x: x, truncate=True):
-        yield bitarray.bitarray(chunk, endian='little').tobytes()
+def _to_bytes(bits):
+    converter = BitPacker()
+    for chunk in common.iterate(data=bits, size=8,
+                                func=tuple, truncate=True):
+        yield [converter.to_byte[chunk]]
 
 
 @chain_wrapper

requirements.txt

@@ -1,4 +1,2 @@
 numpy
-bitarray
-argcomplete
 git+http://people.csail.mit.edu/hubert/git/pyaudio.git

setup.py

@@ -25,7 +25,7 @@ setup(
     packages=['amodem'],
     tests_require=['pytest'],
     cmdclass={'test': PyTest},
-    install_requires=['numpy', 'bitarray', 'argcomplete', 'pyaudio'],
+    install_requires=['numpy', 'argcomplete', 'pyaudio'],
     platforms=['POSIX'],
     classifiers=[
         "Development Status :: 4 - Beta",