int LWZState::ReadByte( RageFile &f )
{
if( fresh )
{
fresh = false;
do {
firstcode = oldcode = m_Code.Get( f, code_size );
} while ( firstcode == clear_code );
return firstcode;
}
if( sp > stack )
return *--sp;
int code;
while( (code = m_Code.Get(f, code_size)) >= 0 )
{
if( code == clear_code )
{
memset( table, 0, sizeof(table) );
for( int i = 0; i < clear_code; ++i )
table[1][i] = i;
code_size = set_code_size + 1;
max_code_size = 2 * clear_code;
max_code = clear_code + 2;
sp = stack;
firstcode = oldcode = m_Code.Get( f, code_size );
return firstcode;
}
else if( code == end_code )
{
int count;
unsigned char buf[260];
if( m_Code.done )
return -2;
while( (count = GetDataBlock(f, buf)) > 0 )
;
if( count != 0 )
{
/*
* pm_message("missing EOD in data stream (common occurence)");
*/
}
return -2;
}
int incode = code;
if( code >= max_code )
{
*sp++ = firstcode;
code = oldcode;
}
while( code >= clear_code )
{
*sp++ = table[1][code];
// if (code == table[0][code])
// RWSetMsg("circular table entry BIG ERROR");
code = table[0][code];
}
*sp++ = firstcode = table[1][code];
if( (code = max_code) < (1 << MAX_LWZ_BITS) )
{
table[0][code] = oldcode;
table[1][code] = firstcode;
++max_code;
if (max_code >= max_code_size &&
max_code_size < (1 << MAX_LWZ_BITS))
{
max_code_size *= 2;
++code_size;
}
}
oldcode = incode;
if( sp > stack )
return *--sp;
}
return code;
}
