private void _bitshift(int num, uint b)
{
starSamples[num].bitsr <<= 1;
starSamples[num].bitsr |= b;
switch (starSamples[num].bitstate)
{
case 0:
{
if ((starSamples[num].bitsr & 0x001f) == 0x0e)
{
starSamples[num].bitstate = 1;
starSamples[num].bitcount = 32 - 5;
}
else if ((starSamples[num].bitsr & 0x001f) == 0x11)
{
starSamples[num].bitsr ^= 0x1f;
starSamples[num].bitstate = 1;
starSamples[num].bitcount = 32 - 5;
starSamples[num].rbit ^= 1;
}
break;
}
case 1:
{
if (--starSamples[num].bitcount == 0)
{
starSamples[num].bits0 = starSamples[num].bitsr;
starSamples[num].bitstate = 2;
starSamples[num].bitcount = 32;
}
break;
}
case 2:
{
if (--starSamples[num].bitcount == 0)
{
starSamples[num].bits1 = starSamples[num].bitsr;
starSamples[num].bitstate = 3;
starSamples[num].bitcount = 16;
}
break;
}
case 3:
{
if (--starSamples[num].bitcount == 0)
{
starSamples[num].bits2 = starSamples[num].bitsr;
starSamples[num].bits2 <<= 16;
starSamples[num].bitstate = 4;
if ((starSamples[num].bits0 & 0x07ff0000) == ((~(starSamples[num].bits1)) & 0x07ff0000))
{
if (DecoderHelpers.STAR_ComputeCDC(starSamples[num].bits0) == (starSamples[num].bits0 & 0x3f) && ((starSamples[num].bits0 & 0x3f) == (starSamples[num].bits1 & 0x3f)))
{
lastBits0 = starSamples[num].bits0;
ClearAllDecoders();
valid = 1;
}
}
}
break;
}
case 4:
{
_reset_decoder(num);
break;
}
}
}
private void ProcBits(int x)
{
bool[] lbits = new bool[112];
int lbc = 0;
int i, j, k;
byte[] data = new byte[14];
ushort ccrc;
ushort rcrc;
for (i = 0; i < 16; i++)
{
for (j = 0; j < 7; j++)
{
k = (j * 16) + i;
lbits[lbc] = mdcSamples[x].bits[k];
++lbc;
}
}
for (i = 0; i < 14; i++)
{
data[i] = 0;
for (j = 0; j < 8; j++)
{
k = (i * 8) + j;
if (lbits[k])
{
data[i] |= (byte)(1 << j);
}
}
}
ccrc = DecoderHelpers.MDC1200_ComputeCRC(data, 4);
rcrc = (ushort)(data[5] << 8 | data[4]);
if (ccrc == rcrc)
{
if (mdcSamples[x].shstate == 2)
{
extra0 = data[0];
extra1 = data[1];
extra2 = data[2];
extra3 = data[3];
for (k = 0; k < MDC_ND; k++)
{
mdcSamples[k].shstate = -1;
}
good = 2;
indouble = 0;
}
else
{
if (indouble <= 0)
{
good = 1;
op = data[0];
arg = data[1];
unitID = (ushort)((data[2] << 8) | data[3]);
crc = (ushort)((data[4] << 8) | data[5]);
switch (data[0])
{
/* list of opcode that mean 'double packet' */
case 0x35:
case 0x55:
good = 0;
indouble = 1;
mdcSamples[x].shstate = 2;
mdcSamples[x].shcount = 0;
ClearBits(x);
break;
default:
// only in the single-packet case, double keeps rest going
for (k = 0; k < MDC_ND; k++)
{
mdcSamples[k].shstate = -1;
}
break;
}
}
else
{
// any subsequent good decoder allowed to attempt second half
mdcSamples[x].shstate = 2;
mdcSamples[x].shcount = 0;
ClearBits(x);
}
}
}
else
{
mdcSamples[x].shstate = -1;
}
if (good > 0)
{
ProcessGoodMDC(good, op, arg, unitID, extra0, extra1, extra2, extra3);
good = 0;
}
}
