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Diffstat (limited to 'gr-dtv/lib/atsc/atsc_randomize.h')
-rw-r--r--gr-dtv/lib/atsc/atsc_randomize.h109
1 files changed, 56 insertions, 53 deletions
diff --git a/gr-dtv/lib/atsc/atsc_randomize.h b/gr-dtv/lib/atsc/atsc_randomize.h
index 0903240f48..48331cdab8 100644
--- a/gr-dtv/lib/atsc/atsc_randomize.h
+++ b/gr-dtv/lib/atsc/atsc_randomize.h
@@ -26,67 +26,70 @@
#include "atsc_types.h"
namespace gr {
- namespace dtv {
+namespace dtv {
- class atsc_randomize
+class atsc_randomize
+{
+public:
+ atsc_randomize();
+
+ /*! \brief reset randomizer LFSR
+ *
+ * must be called during the Data Segment Sync interval prior to the
+ * first data segment. I.e., the LFSR is reset prior to the first
+ * field of each VSB data frame.
+ */
+ void reset();
+
+ //! randomize (whiten) mpeg packet and remove leading MPEG-2 sync byte
+ void randomize(atsc_mpeg_packet_no_sync& out, const atsc_mpeg_packet& in);
+
+ //! derandomize (de-whiten) mpeg packet and add leading MPEG-2 sync byte
+ void derandomize(atsc_mpeg_packet& out, const atsc_mpeg_packet_no_sync& in);
+
+ unsigned int state() const { return d_state; }
+
+private:
+ static void initialize_output_map();
+ static unsigned char slow_output_map(int st);
+
+ static unsigned char fast_output_map(int st)
+ {
+ return s_output_map[(st & 0xb23c) >>
+ 2]; // Magic const with 8 bits set improves cache
+ // utilization. The bits correspond to the taps
+ // used in output calculation. Others may be
+ // safely ignored.
+ }
+
+ //! return current output value
+ unsigned char output() { return fast_output_map(d_state); }
+
+ //! clock LFSR; advance to next state.
+ void clk()
{
- public:
- atsc_randomize();
-
- /*! \brief reset randomizer LFSR
- *
- * must be called during the Data Segment Sync interval prior to the
- * first data segment. I.e., the LFSR is reset prior to the first
- * field of each VSB data frame.
- */
- void reset ();
-
- //! randomize (whiten) mpeg packet and remove leading MPEG-2 sync byte
- void randomize (atsc_mpeg_packet_no_sync &out, const atsc_mpeg_packet &in);
-
- //! derandomize (de-whiten) mpeg packet and add leading MPEG-2 sync byte
- void derandomize (atsc_mpeg_packet &out, const atsc_mpeg_packet_no_sync &in);
-
- unsigned int state() const { return d_state; }
- private:
- static void initialize_output_map ();
- static unsigned char slow_output_map (int st);
-
- static unsigned char fast_output_map (int st){
- return s_output_map[(st & 0xb23c) >> 2]; // Magic const with 8 bits set improves cache
- // utilization. The bits correspond to the taps
- // used in output calculation. Others may be
- // safely ignored.
- }
-
- //! return current output value
- unsigned char output (){
- return fast_output_map (d_state);
- }
-
- //! clock LFSR; advance to next state.
- void clk (){
if (d_state & 0x1)
- d_state = ((d_state ^ MASK) >> 1) | 0x8000;
+ d_state = ((d_state ^ MASK) >> 1) | 0x8000;
else
- d_state = d_state >> 1;
- }
+ d_state = d_state >> 1;
+ }
- //! return current output value and advance to next state
- unsigned char output_and_clk (){
- unsigned char r = output ();
- clk ();
+ //! return current output value and advance to next state
+ unsigned char output_and_clk()
+ {
+ unsigned char r = output();
+ clk();
return r;
- }
+ }
- unsigned int d_state;
+ unsigned int d_state;
- static const unsigned int PRELOAD_VALUE = 0x018f; /* 0xf180 bit reversed */
- static const unsigned int MASK = 0xa638;
- static unsigned char s_output_map[1 << 14];
- static bool s_output_map_initialized_p;
- };
- } /* namespace dtv */
+ static const unsigned int PRELOAD_VALUE = 0x018f; /* 0xf180 bit reversed */
+ static const unsigned int MASK = 0xa638;
+ static unsigned char s_output_map[1 << 14];
+ static bool s_output_map_initialized_p;
+};
+} /* namespace dtv */
} /* namespace gr */
#endif /* INCLUDED_ATSC_RANDOMIZE_H */