remove base32 crockford in favor of dependency

archivebox/base32_crockford.py

@@ -1,172 +0,0 @@
-"""
-base32-crockford
-================
-
-A Python module implementing the alternate base32 encoding as described
-by Douglas Crockford at: http://www.crockford.com/wrmg/base32.html.
-
-He designed the encoding to:
-
-   * Be human and machine readable
-   * Be compact
-   * Be error resistant
-   * Be pronounceable
-
-It uses a symbol set of 10 digits and 22 letters, excluding I, L O and
-U. Decoding is not case sensitive, and 'i' and 'l' are converted to '1'
-and 'o' is converted to '0'. Encoding uses only upper-case characters.
-
-Hyphens may be present in symbol strings to improve readability, and
-are removed when decoding.
-
-A check symbol can be appended to a symbol string to detect errors
-within the string.
-
-"""
-
-import re
-import sys
-
-PY3 = sys.version_info[0] == 3
-
-if not PY3:
-    import string as str
-
-
-__all__ = ["encode", "decode", "normalize"]
-
-
-if PY3:
-    string_types = str,
-else:
-    string_types = basestring,
-
-# The encoded symbol space does not include I, L, O or U
-symbols = '0123456789ABCDEFGHJKMNPQRSTVWXYZ'
-# These five symbols are exclusively for checksum values
-check_symbols = '*~$=U'
-
-encode_symbols = dict((i, ch) for (i, ch) in enumerate(symbols + check_symbols))
-decode_symbols = dict((ch, i) for (i, ch) in enumerate(symbols + check_symbols))
-normalize_symbols = str.maketrans('IiLlOo', '111100')
-valid_symbols = re.compile('^[%s]+[%s]?$' % (symbols,
-                                             re.escape(check_symbols)))
-
-base = len(symbols)
-check_base = len(symbols + check_symbols)
-
-
-def encode(number, checksum=False, split=0):
-    """Encode an integer into a symbol string.
-
-    A ValueError is raised on invalid input.
-
-    If checksum is set to True, a check symbol will be
-    calculated and appended to the string.
-
-    If split is specified, the string will be divided into
-    clusters of that size separated by hyphens.
-
-    The encoded string is returned.
-    """
-    number = int(number)
-    if number < 0:
-        raise ValueError("number '%d' is not a positive integer" % number)
-
-    split = int(split)
-    if split < 0:
-        raise ValueError("split '%d' is not a positive integer" % split)
-
-    check_symbol = ''
-    if checksum:
-        check_symbol = encode_symbols[number % check_base]
-
-    if number == 0:
-        return '0' + check_symbol
-
-    symbol_string = ''
-    while number > 0:
-        remainder = number % base
-        number //= base
-        symbol_string = encode_symbols[remainder] + symbol_string
-    symbol_string = symbol_string + check_symbol
-
-    if split:
-        chunks = []
-        for pos in range(0, len(symbol_string), split):
-            chunks.append(symbol_string[pos:pos + split])
-        symbol_string = '-'.join(chunks)
-
-    return symbol_string
-
-
-def decode(symbol_string, checksum=False, strict=False):
-    """Decode an encoded symbol string.
-
-    If checksum is set to True, the string is assumed to have a
-    trailing check symbol which will be validated. If the
-    checksum validation fails, a ValueError is raised.
-
-    If strict is set to True, a ValueError is raised if the
-    normalization step requires changes to the string.
-
-    The decoded string is returned.
-    """
-    symbol_string = normalize(symbol_string, strict=strict)
-    if checksum:
-        symbol_string, check_symbol = symbol_string[:-1], symbol_string[-1]
-
-    number = 0
-    for symbol in symbol_string:
-        number = number * base + decode_symbols[symbol]
-
-    if checksum:
-        check_value = decode_symbols[check_symbol]
-        modulo = number % check_base
-        if check_value != modulo:
-            raise ValueError("invalid check symbol '%s' for string '%s'" %
-                             (check_symbol, symbol_string))
-
-    return number
-
-
-def normalize(symbol_string, strict=False):
-    """Normalize an encoded symbol string.
-
-    Normalization provides error correction and prepares the
-    string for decoding. These transformations are applied:
-
-       1. Hyphens are removed
-       2. 'I', 'i', 'L' or 'l' are converted to '1'
-       3. 'O' or 'o' are converted to '0'
-       4. All characters are converted to uppercase
-
-    A TypeError is raised if an invalid string type is provided.
-
-    A ValueError is raised if the normalized string contains
-    invalid characters.
-
-    If the strict parameter is set to True, a ValueError is raised
-    if any of the above transformations are applied.
-
-    The normalized string is returned.
-    """
-    if isinstance(symbol_string, string_types):
-        if not PY3:
-            try:
-                symbol_string = symbol_string.encode('ascii')
-            except UnicodeEncodeError:
-                raise ValueError("string should only contain ASCII characters")
-    else:
-        raise TypeError("string is of invalid type %s" %
-                        symbol_string.__class__.__name__)
-
-    norm_string = symbol_string.replace('-', '').translate(normalize_symbols).upper()
-
-    if not valid_symbols.match(norm_string):
-        raise ValueError("string '%s' contains invalid characters" % norm_string)
-
-    if strict and norm_string != symbol_string:
-        raise ValueError("string '%s' requires normalization" % symbol_string)
-
-    return norm_string