_groupLength(0),

_groupIndex(0),

_buf(*istr.rdbuf())

{

FastMutex::ScopedLock lock(mutex);

if (!IN_ENCODING_INIT)

{

for (unsigned i = 0; i < sizeof(IN_ENCODING); i++)

{

IN_ENCODING[i] = 0xFF;

}

for (unsigned i = 0; i < sizeof(Base32EncoderBuf::OUT_ENCODING); i++)

{

IN_ENCODING[Base32EncoderBuf::OUT_ENCODING[i]] = static_cast<UInt8>(i);

}

IN_ENCODING[static_cast<unsigned char>('=')] = '\0';

IN_ENCODING_INIT = true;

}

{

if (_groupIndex < _groupLength)

{

return _group[_groupIndex++];

}

else

{

unsigned char buffer[8];

std::memset(buffer, '=', sizeof(buffer));

int c;

// per RFC-4648, Section 6, permissible block lengths are:

// 2, 4, 5, 7, and 8 bytes. Any other length is malformed.

//

do {

if ((c = readOne()) == -1) return -1;

buffer[0] = (unsigned char) c;

if (IN_ENCODING[buffer[0]] == 0xFF) throw DataFormatException();

if ((c = readOne()) == -1) throw DataFormatException();

buffer[1] = (unsigned char) c;

if (IN_ENCODING[buffer[1]] == 0xFF) throw DataFormatException();

if ((c = readOne()) == -1) break;

buffer[2] = (unsigned char) c;

if (IN_ENCODING[buffer[2]] == 0xFF) throw DataFormatException();

if ((c = readOne()) == -1) throw DataFormatException();

buffer[3] = (unsigned char) c;

if (IN_ENCODING[buffer[3]] == 0xFF) throw DataFormatException();

if ((c = readOne()) == -1) break;

buffer[4] = (unsigned char) c;

if (IN_ENCODING[buffer[4]] == 0xFF) throw DataFormatException();

if ((c = readOne()) == -1) break;

buffer[5] = (unsigned char) c;

if (IN_ENCODING[buffer[5]] == 0xFF) throw DataFormatException();

if ((c = readOne()) == -1) throw DataFormatException();

buffer[6] = (unsigned char) c;

if (IN_ENCODING[buffer[6]] == 0xFF) throw DataFormatException();

if ((c = readOne()) == -1) break;

buffer[7] = (unsigned char) c;

if (IN_ENCODING[buffer[7]] == 0xFF) throw DataFormatException();

} while (false);

_group[0] = (IN_ENCODING[buffer[0]] << 3) | (IN_ENCODING[buffer[1]] >> 2);

_group[1] = ((IN_ENCODING[buffer[1]] & 0x03) << 6) | (IN_ENCODING[buffer[2]] << 1) | (IN_ENCODING[buffer[3]] >> 4);

_group[2] = ((IN_ENCODING[buffer[3]] & 0x0F) << 4) | (IN_ENCODING[buffer[4]] >> 1);

_group[3] = ((IN_ENCODING[buffer[4]] & 0x01) << 7) | (IN_ENCODING[buffer[5]] << 2) | (IN_ENCODING[buffer[6]] >> 3);

_group[4] = ((IN_ENCODING[buffer[6]] & 0x07) << 5) | IN_ENCODING[buffer[7]];

if (buffer[2] == '=')

_groupLength = 1;

else if (buffer[4] == '=')

_groupLength = 2;

else if (buffer[5] == '=')

_groupLength = 3;

else if (buffer[7] == '=')

_groupLength = 4;

else

_groupLength = 5;

_groupIndex = 1;

return _group[0];

}

{

int ch = _buf.sbumpc();

return ch;