lint pass

Author: brentru

LICENSE

@@ -1,6 +1,7 @@
 The MIT License (MIT)
 
-Copyright (c) 2019 Brent Rubell  for Adafruit Industries.
+Copyright (c) 2017 Paul Sokolovsky
+Modified by Brent Rubell  for Adafruit Industries, 2019
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

adafruit_binascii.py

@@ -1,6 +1,7 @@
 # The MIT License (MIT)
 #
-# Copyright (c) 2019 Brent Rubell  for Adafruit Industries.
+# Copyright (c) 2014 Paul Sokolovsky
+# Modified by Brent Rubell for Adafruit Industries, 2019
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -26,28 +27,153 @@
 Helpers for conversions between binary and ASCII
 
 
-* Author(s): Brent Rubell 
+* Author(s): Paul Sokolovsky, Brent Rubell
 
 Implementation Notes
 --------------------
 
 **Hardware:**
 
-.. todo:: Add links to any specific hardware product page(s), or category page(s). Use unordered list & hyperlink rST
-   inline format: "* `Link Text <url>`_"
-
 **Software and Dependencies:**
 
 * Adafruit CircuitPython firmware for the supported boards:
   https://github.com/adafruit/circuitpython/releases
 
-.. todo:: Uncomment or remove the Bus Device and/or the Register library dependencies based on the library's use of either.
-
-# * Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
-# * Adafruit's Register library: https://github.com/adafruit/Adafruit_CircuitPython_Register
 """
-
-# imports
+try:
+    from binascii import hexlify, unhexlify
+except ImportError:
+    pass
 
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_binascii.git"
+
+# pylint: disable=bad-whitespace
+TABLE_A2B_B64 = [
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, 62, -1, -1, -1, 63,
+    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1,  -1, -1,  -1, -1, -1,
+    -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
+    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,-1,  -1,  -1,  -1, -1,
+    -1,  26, 27, 28, 29, 30,31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,-1, -1, -1, -1, -1,
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1,
+]
+
+
+if not "unhexlify" in globals():
+    # pylint: disable=function-redefined
+    def unhexlify(hexstr):
+        """Return the binary data represented by hexstr.
+        :param str hexstr: Hexadecimal string.
+        """
+        if len(hexstr) % 2 != 0:
+            raise ValueError("Odd-length string")
+
+        return bytes([int(hexstr[i : i + 2], 16) for i in range(0, len(hexstr), 2)])
+
+
+if not "hexlify" in globals():
+    # pylint: disable=function-redefined
+    def hexlify(data):
+        """Return the hexadecimal representation of the
+        binary data. Every byte of data is converted into
+        the corresponding 2-digit hex representation.
+        The returned bytes object is therefore twice
+        as long as the length of data.
+
+        :param bytes data: Binary data, as bytes.
+        """
+        if not data:
+            raise TypeError("Data provided is zero-length")
+        data = "".join("%02x" % i for i in data)
+        return data.encode()
+
+B2A_HEX = hexlify
+A2B_HEX = unhexlify
+
+def _transform(n):
+    if n == -1:
+        return '\xff'
+    return chr(n)
+TABLE_A2B_B64 = ''.join(map(_transform, TABLE_A2B_B64))
+assert len(TABLE_A2B_B64) == 256
+
+def a2b_base64(b64_data):
+    "Decode a line of base64 data."
+    res = []
+    quad_pos = 0
+    leftchar = 0
+    leftbits = 0
+    last_char_was_a_pad = False
+
+    for char in b64_data:
+        char = chr(char)
+        if char == "=":
+            if quad_pos > 2 or (quad_pos == 2 and last_char_was_a_pad):
+                break      # stop on 'xxx=' or on 'xx=='
+            last_char_was_a_pad = True
+        else:
+            n = ord(TABLE_A2B_B64[ord(char)])
+            if n == 0xff:
+                continue    # ignore strange characters
+            #
+            # Shift it in on the low end, and see if there's
+            # a byte ready for output.
+            quad_pos = (quad_pos + 1) & 3
+            leftchar = (leftchar << 6) | n
+            leftbits += 6
+            #
+            if leftbits >= 8:
+                leftbits -= 8
+                res.append((leftchar >> leftbits).to_bytes(1, 'big'))
+                leftchar &= ((1 << leftbits) - 1)
+            #
+            last_char_was_a_pad = False
+    else:
+        if leftbits != 0:
+            raise Exception("Incorrect padding")
+
+    return b''.join(res)
+
+# ____________________________________________________________
+
+TABLE_B2A_B64 = (
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
+
+def b2a_base64(bin_data):
+    "Base64-code line of data."
+
+    newlength = (len(bin_data) + 2) // 3
+    newlength = newlength * 4 + 1
+    res = []
+
+    leftchar = 0
+    leftbits = 0
+    for char in bin_data:
+        # Shift into our buffer, and output any 6bits ready
+        leftchar = (leftchar << 8) | char
+        leftbits += 8
+        res.append(TABLE_B2A_B64[(leftchar >> (leftbits-6)) & 0x3f])
+        leftbits -= 6
+        if leftbits >= 6:
+            res.append(TABLE_B2A_B64[(leftchar >> (leftbits-6)) & 0x3f])
+            leftbits -= 6
+    #
+    if leftbits == 2:
+        res.append(TABLE_B2A_B64[(leftchar & 3) << 4])
+        res.append("=")
+        res.append("=")
+    elif leftbits == 4:
+        res.append(TABLE_B2A_B64[(leftchar & 0xf) << 2])
+        res.append("=")
+    res.append('\n')
+    return ''.join(res).encode('ascii')