void Gunzip::ProcessPrestreamHeader()
{
m_length = 0;
m_crc.Restart();
byte buf[6];
byte b, flags;
if (m_inQueue.Get(buf, 2)!=2) throw HeaderErr();
if (buf[0] != MAGIC1 || buf[1] != MAGIC2) throw HeaderErr();
if (!m_inQueue.Skip(1)) throw HeaderErr(); // skip extra flags
if (!m_inQueue.Get(flags)) throw HeaderErr();
if (flags & (ENCRYPTED | CONTINUED)) throw HeaderErr();
if (m_inQueue.Skip(6)!=6) throw HeaderErr(); // Skip file time, extra flags and OS type
if (flags & EXTRA_FIELDS) // skip extra fields
{
word16 length;
if (m_inQueue.GetWord16(length, LITTLE_ENDIAN_ORDER) != 2) throw HeaderErr();
if (m_inQueue.Skip(length)!=length) throw HeaderErr();
}
if (flags & FILENAME) // skip filename
do
if(!m_inQueue.Get(b)) throw HeaderErr();
while (b);
if (flags & COMMENTS) // skip comments
do
if(!m_inQueue.Get(b)) throw HeaderErr();
while (b);
}
void Gunzip::ProcessHeader()
{
byte buf[6];
byte b, flags;
if (inQueue.Get(buf, 2)!=2) goto error;
if (buf[0] != MAGIC1 || buf[1] != MAGIC2) goto error;
if (!inQueue.Skip(1)) goto error; // skip extra flags
if (!inQueue.Get(flags)) goto error;
if (flags & (ENCRYPTED | CONTINUED)) goto error;
if (inQueue.Skip(6)!=6) goto error; // Skip file time, extra flags and OS type
if (flags & EXTRA_FIELDS) // skip extra fields
{
word16 length;
if(!inQueue.GetShort(length, false)) goto error;
if (inQueue.Skip(length)!=length) goto error;
}
if (flags & FILENAME) // skip filename
do
if(!inQueue.Get(b)) goto error;
while (b);
if (flags & COMMENTS) // skip comments
do
if(!inQueue.Get(b)) goto error;
while (b);
inQueue.TransferTo(inflater);
state = PROCESS_BODY;
return;
error:
throw HeaderErr();
}
