leansdr::etr192_descrambler Struct Reference

#include <iess.h>

Inheritance diagram for leansdr::etr192_descrambler:

Collaboration diagram for leansdr::etr192_descrambler:

Public Member Functions
	etr192_descrambler (scheduler *sch, pipebuf< u8 > &_in, pipebuf< u8 > &_out)
void	run ()
Public Member Functions inherited from leansdr::runnable
	runnable (scheduler *_sch, const char *name)
Public Member Functions inherited from leansdr::runnable_common
	runnable_common (const char *_name)
virtual	~runnable_common ()
virtual void	shutdown ()

Private Attributes
pipereader< u8 >	in
pipewriter< u8 >	out
u32	shiftreg
u8	counter

Additional Inherited Members
Public Attributes inherited from leansdr::runnable_common
const char *	name
Protected Attributes inherited from leansdr::runnable
scheduler *	sch

Detailed Description

Definition at line 29 of file iess.h.

Constructor & Destructor Documentation

etr192_descrambler()

leansdr::etr192_descrambler::etr192_descrambler ( scheduler *  sch, pipebuf< u8 > &  _in, pipebuf< u8 > &  _out  )

inline

Definition at line 31 of file iess.h.

        : runnable(sch, "etr192_dec"),
          in(_in), out(_out),
          shiftreg(0), counter(0)
    {
    }

Member Function Documentation

run()

void leansdr::etr192_descrambler::run ( )

inlinevirtual

Reimplemented from leansdr::runnable_common.

Definition at line 40 of file iess.h.

References counter, in, leansdr::min(), out, leansdr::pipereader< T >::rd(), leansdr::pipereader< T >::read(), leansdr::pipereader< T >::readable(), shiftreg, leansdr::pipewriter< T >::wr(), leansdr::pipewriter< T >::writable(), and leansdr::pipewriter< T >::written().

    {
        int count = min(in.readable(), out.writable());
        for (u8 *pin = in.rd(), *pend = pin + count, *pout = out.wr();
             pin < pend; ++pin, ++pout)
        {
            u8 byte_in = *pin, byte_out = 0;
            for (int b = 8; b--; byte_in <<= 1)
            {
                // Levels before clock transition
                int bit_in = (byte_in & 128) ? 1 : 0;
                int reset_counter = (shiftreg ^ (shiftreg >> 8)) & 1;
                int counter_overflow = (counter == 31) ? 1 : 0;
                int taps = (shiftreg >> 2) ^ (shiftreg >> 19);
                int bit_out = (taps ^ counter_overflow ^ bit_in ^ 1) & 1;
                // Execute clock transition
#if 1 // Descramble
                shiftreg = (shiftreg << 1) | bit_in;
#else // Scramble
                shiftreg = (shiftreg << 1) | bit_out;
#endif
                counter = reset_counter ? 0 : (counter + 1) & 31;
                byte_out = (byte_out << 1) | bit_out;
            }
            *pout = byte_out;
        }
        in.read(count);
        out.written(count);
    }

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Member Data Documentation

counter

u8 leansdr::etr192_descrambler::counter

private

Definition at line 74 of file iess.h.

Referenced by run().

in

pipereader<u8> leansdr::etr192_descrambler::in

private

Definition at line 71 of file iess.h.

Referenced by run().

out

pipewriter<u8> leansdr::etr192_descrambler::out

private

Definition at line 72 of file iess.h.

Referenced by run().

shiftreg

u32 leansdr::etr192_descrambler::shiftreg

private

Definition at line 73 of file iess.h.

Referenced by run().

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The documentation for this struct was generated from the following file:

• plugins/channelrx/demoddatv/leansdr/iess.h