"binascii" --- Converte entre binário e ASCII
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The "binascii" module contains a number of methods to convert between
binary and various ASCII-encoded binary representations. Normally, you
will not use these functions directly but use wrapper modules like
"uu", "base64", or "binhex" instead. The "binascii" module contains
low-level functions written in C for greater speed that are used by
the higher-level modules.

Nota:

  Funções "a2b_*" aceitam strings Unicode contendo apenas caracteres
  ASCII. Outras funções aceitam apenas *objetos bytes ou similares*
  (como "bytes", "bytearray" e outros objetos que suportam o protocolo
  buffer).

  Alterado na versão 3.3: Strings unicode exclusivamente ASCII agora
  são aceitas pelas funções "a2b_*".

O módulo "binascii" define as seguintes funções:

binascii.a2b_uu(string)

   Converte uma única linha de dados uuencoded de volta para binário e
   retorna os dados binários. As linhas normalmente contêm 45 bytes
   (binários), exceto a última linha. Os dados da linha podem ser
   seguidos por espaços em branco.

binascii.b2a_uu(data, *, backtick=False)

   Converte dados binários para uma linha de caracteres ASCII, o valor
   de retorno é a linha convertida, incluindo um caractere de nova
   linha. O comprimento de *data* deve ser no máximo 45. Se *backtick*
   for true, zeros são representados por "'`'" em vez de espaços.

   Alterado na versão 3.7: Adicionado o parâmetro *backtick*.

binascii.a2b_base64(string)

   Converte um bloco de dados base64 de volta para binário e retorna
   os dados binários. Mais de uma linha pode ser passada por vez.

binascii.b2a_base64(data, *, newline=True)

   Converte dados binários para uma linha de caracteres ASCII em
   codificação base64. O valor de retorno é a linha convertida,
   incluindo um caractere de nova linha se *newline* for verdadeiro. A
   saída desta função está em conformidade com **RFC 3548**.

   Alterado na versão 3.6: Adicionado o parâmetro *newline*.

binascii.a2b_qp(data, header=False)

   Convert a block of quoted-printable data back to binary and return
   the binary data. More than one line may be passed at a time. If the
   optional argument *header* is present and true, underscores will be
   decoded as spaces.

binascii.b2a_qp(data, quotetabs=False, istext=True, header=False)

   Convert binary data to a line(s) of ASCII characters in quoted-
   printable encoding.  The return value is the converted line(s). If
   the optional argument *quotetabs* is present and true, all tabs and
   spaces will be encoded.   If the optional argument *istext* is
   present and true, newlines are not encoded but trailing whitespace
   will be encoded. If the optional argument *header* is present and
   true, spaces will be encoded as underscores per **RFC 1522**. If
   the optional argument *header* is present and false, newline
   characters will be encoded as well; otherwise linefeed conversion
   might corrupt the binary data stream.

binascii.a2b_hqx(string)

   Convert binhex4 formatted ASCII data to binary, without doing RLE-
   decompression. The string should contain a complete number of
   binary bytes, or (in case of the last portion of the binhex4 data)
   have the remaining bits zero.

   Obsoleto desde a versão 3.9.

binascii.rledecode_hqx(data)

   Perform RLE-decompression on the data, as per the binhex4 standard.
   The algorithm uses "0x90" after a byte as a repeat indicator,
   followed by a count. A count of "0" specifies a byte value of
   "0x90". The routine returns the decompressed data, unless data
   input data ends in an orphaned repeat indicator, in which case the
   "Incomplete" exception is raised.

   Alterado na versão 3.2: Accept only bytestring or bytearray objects
   as input.

   Obsoleto desde a versão 3.9.

binascii.rlecode_hqx(data)

   Perform binhex4 style RLE-compression on *data* and return the
   result.

   Obsoleto desde a versão 3.9.

binascii.b2a_hqx(data)

   Perform hexbin4 binary-to-ASCII translation and return the
   resulting string. The argument should already be RLE-coded, and
   have a length divisible by 3 (except possibly the last fragment).

   Obsoleto desde a versão 3.9.

binascii.crc_hqx(data, value)

   Compute a 16-bit CRC value of *data*, starting with *value* as the
   initial CRC, and return the result.  This uses the CRC-CCITT
   polynomial *x*^16 + *x*^12 + *x*^5 + 1, often represented as
   0x1021.  This CRC is used in the binhex4 format.

binascii.crc32(data[, value])

   Compute CRC-32, the unsigned 32-bit checksum of *data*, starting
   with an initial CRC of *value*.  The default initial CRC is zero.
   The algorithm is consistent with the ZIP file checksum.  Since the
   algorithm is designed for use as a checksum algorithm, it is not
   suitable for use as a general hash algorithm.  Use as follows:

      print(binascii.crc32(b"hello world"))
      # Or, in two pieces:
      crc = binascii.crc32(b"hello")
      crc = binascii.crc32(b" world", crc)
      print('crc32 = {:#010x}'.format(crc))

   Alterado na versão 3.0: The result is always unsigned. To generate
   the same numeric value when using Python 2 or earlier, use
   "crc32(data) & 0xffffffff".

binascii.b2a_hex(data[, sep[, bytes_per_sep=1]])
binascii.hexlify(data[, sep[, bytes_per_sep=1]])

   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*.

   Similar functionality (but returning a text string) is also
   conveniently accessible using the "bytes.hex()" method.

   If *sep* is specified, it must be a single character str or bytes
   object. It will be inserted in the output after every
   *bytes_per_sep* input bytes. Separator placement is counted from
   the right end of the output by default, if you wish to count from
   the left, supply a negative *bytes_per_sep* value.

   >>> import binascii
   >>> binascii.b2a_hex(b'\xb9\x01\xef')
   b'b901ef'
   >>> binascii.hexlify(b'\xb9\x01\xef', '-')
   b'b9-01-ef'
   >>> binascii.b2a_hex(b'\xb9\x01\xef', b'_', 2)
   b'b9_01ef'
   >>> binascii.b2a_hex(b'\xb9\x01\xef', b' ', -2)
   b'b901 ef'

   Alterado na versão 3.8: The *sep* and *bytes_per_sep* parameters
   were added.

binascii.a2b_hex(hexstr)
binascii.unhexlify(hexstr)

   Return the binary data represented by the hexadecimal string
   *hexstr*.  This function is the inverse of "b2a_hex()". *hexstr*
   must contain an even number of hexadecimal digits (which can be
   upper or lower case), otherwise an "Error" exception is raised.

   Similar functionality (accepting only text string arguments, but
   more liberal towards whitespace) is also accessible using the
   "bytes.fromhex()" class method.

exception binascii.Error

   Exception raised on errors. These are usually programming errors.

exception binascii.Incomplete

   Exception raised on incomplete data. These are usually not
   programming errors, but may be handled by reading a little more
   data and trying again.

Ver também:

  Módulo "base64"
     Support for RFC compliant base64-style encoding in base 16, 32,
     64, and 85.

  Module "binhex"
     Support for the binhex format used on the Macintosh.

  Module "uu"
     Support for UU encoding used on Unix.

  Módulo "quopri"
     Support for quoted-printable encoding used in MIME email
     messages.
