private S3m_header LoadHeader(BinaryReader br)
{
var h = new S3m_header();
h.name = new string(br.ReadChars(28));
h.kennung = br.ReadByte(); h.typ = br.ReadByte();
br.BaseStream.Seek(2, SeekOrigin.Current);
h.ordnum = br.ReadUInt16(); h.insnum = br.ReadUInt16();
h.patnum = br.ReadUInt16(); h.flags = br.ReadUInt16();
h.cwtv = br.ReadUInt16(); h.ffi = br.ReadUInt16();
h.scrm = new string(br.ReadChars(4));
h.gv = br.ReadByte(); h.@is = br.ReadByte(); h.it = br.ReadByte();
h.mv = br.ReadByte(); h.uc = br.ReadByte(); h.dp = br.ReadByte();
br.BaseStream.Seek(8, SeekOrigin.Current);
h.special = br.ReadUInt16();
h.chanset = br.ReadBytes(32);
return(h);
}
public bool Load(Stream stream)
{
var br = new BinaryReader(stream);
var insptr = new ushort[99];
var pattptr = new ushort[99];
int row;
byte bufval, bufval2;
ushort ppatlen;
var adlibins = false;
// file validation section
var checkhead = LoadHeader(br);
if (checkhead.kennung != 0x1a || checkhead.typ != 16 ||
checkhead.insnum > 99)
{
return(false);
}
if (checkhead.scrm != "SCRM")
{
return(false);
}
stream.Seek(checkhead.ordnum, SeekOrigin.Current);
for (var i = 0; i < checkhead.insnum; i++)
{
insptr[i] = br.ReadUInt16();
}
for (var i = 0; i < checkhead.insnum; i++)
{
stream.Seek(insptr[i] * 16, SeekOrigin.Begin);
if (br.ReadByte() >= 2)
{
adlibins = true;
break;
}
}
if (!adlibins)
{
return(false);
}
// load section
stream.Seek(0, SeekOrigin.Begin); // rewind for load
_header = LoadHeader(br); // read header
// security check
if (_header.ordnum > 256 || _header.insnum > 99 || _header.patnum > 99)
{
return(false);
}
for (var i = 0; i < _header.ordnum; i++)
{
_orders[i] = br.ReadByte(); // read orders
}
for (var i = 0; i < _header.insnum; i++)
{
insptr[i] = br.ReadUInt16(); // instrument parapointers
}
for (var i = 0; i < _header.patnum; i++)
{
pattptr[i] = br.ReadUInt16(); // pattern parapointers
}
for (var i = 0; i < _header.insnum; i++)
{ // load instruments
stream.Seek(insptr[i] * 16, SeekOrigin.Begin);
_inst[i].type = br.ReadByte();
_inst[i].filename = new string(br.ReadChars(15));
_inst[i].d00 = br.ReadByte(); _inst[i].d01 = br.ReadByte();
_inst[i].d02 = br.ReadByte(); _inst[i].d03 = br.ReadByte();
_inst[i].d04 = br.ReadByte(); _inst[i].d05 = br.ReadByte();
_inst[i].d06 = br.ReadByte(); _inst[i].d07 = br.ReadByte();
_inst[i].d08 = br.ReadByte(); _inst[i].d09 = br.ReadByte();
_inst[i].d0a = br.ReadByte(); _inst[i].d0b = br.ReadByte();
_inst[i].volume = br.ReadByte(); _inst[i].dsk = br.ReadByte();
stream.Seek(2, SeekOrigin.Current);
_inst[i].c2spd = br.ReadUInt32();
stream.Seek(12, SeekOrigin.Current);
_inst[i].name = new string(br.ReadChars(28));
_inst[i].scri = new string(br.ReadChars(4));
}
for (var i = 0; i < _header.patnum; i++)
{ // depack patterns
stream.Seek(pattptr[i] * 16, SeekOrigin.Begin);
ppatlen = br.ReadUInt16();
long pattpos = stream.Position;
for (row = 0; (row < 64) && (pattpos - pattptr[i] * 16 <= ppatlen); row++)
{
do
{
bufval = br.ReadByte();
if ((bufval & 32) != 0)
{
bufval2 = br.ReadByte();
_pattern[i, row, bufval & 31].note = (byte)(bufval2 & 15);
_pattern[i, row, bufval & 31].oct = (byte)((bufval2 & 240) >> 4);
_pattern[i, row, bufval & 31].instrument = br.ReadByte();
}
if ((bufval & 64) != 0)
{
_pattern[i, row, bufval & 31].volume = br.ReadByte();
}
if ((bufval & 128) != 0)
{
_pattern[i, row, bufval & 31].command = br.ReadByte();
_pattern[i, row, bufval & 31].info = br.ReadByte();
}
} while (bufval != 0);
}
}
Rewind(0);
return(true); // done
}
