public static string ReadString(MemBlock b, int offset, out int bytelength)
{
int null_idx = b.IndexOf(0, offset);
int raw_length = null_idx - offset;
bytelength = raw_length + 1; //One for the null
Encoding e;
/*
* Benchmarks of mono show this to be about twice as fast as just
* using UTF8. That really means UTF8 could be optimized in mono
*/
if( b.IsAscii(offset, raw_length) ) {
e = Encoding.ASCII;
} else {
e = Encoding.UTF8;
}
return b.GetString(e, offset, raw_length);
}
/**
* Parse the PType starting at mb, and return all of mb <b>after</b>
* the PType.
*/
public static PType Parse(MemBlock mb, out MemBlock rest) {
PType result = null;
byte fb = mb[0];
bool is_v_n = IsValidNumeric( (int)fb );
/**
* Since ptypes must be valid UTF8 strings,
* if the second byte is null, the first byte is an ascii character
* and hence has a value less than ASCII_UPPER_BOUND
*/
bool store_in_tbl = ( is_v_n || (mb[1] == 0) );
if( store_in_tbl ) {
//This is stored in our table:
result = _table[ fb ];
if( result != null ) {
if( is_v_n ) {
//There is no null
rest = mb.Slice(1);
}
else {
//Skip the null
rest = mb.Slice(2);
}
return result;
}
}
//Otherwise we have to make it:
MemBlock raw_data = null;
result = new PType();
if( is_v_n ) {
/*
* Don't set the raw_data since it is only one byte and we may not need
* it
*/
rest = mb.Slice(1);
result._type_num = (int)fb;
}
else {
int null_pos = mb.IndexOf(0);
if( null_pos > 0 ) {
//Include the "null", but make a copy so we don't keep some data in
//scope for ever
raw_data = MemBlock.Copy( (ICopyable)mb.Slice(0, null_pos + 1) );
rest = mb.Slice(null_pos + 1);
}
else {
//There is no terminating Null, panic!!
throw new ParseException(
System.String.Format("PType not null terminated: {0}", mb.ToBase16String()));
}
result._type_num = -2;
result._raw_data = raw_data;
}
if( store_in_tbl ) {
//Make sure we don't have to create an object like this again
_table[ fb ] = result;
}
return result;
}
