1 /* -*- c++ -*- */
2 /*
3  * Copyright 2015 Free Software Foundation, Inc.
4  *
5  * This file is part of GNU Radio
6  *
7  * GNU Radio is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 3, or (at your option)
10  * any later version.
11  *
12  * GNU Radio is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with GNU Radio; see the file COPYING.  If not, write to
19  * the Free Software Foundation, Inc., 51 Franklin Street,
20  * Boston, MA 02110-1301, USA.
21  */
22 
23 
24 #ifndef INCLUDED_FEC_POLAR_ENCODER_H
25 #define INCLUDED_FEC_POLAR_ENCODER_H
26 
27 #include <gnuradio/fec/api.h>
28 #include <gnuradio/fec/generic_encoder.h>
29 #include <gnuradio/fec/polar_common.h>
30 
31 namespace gr {
32 namespace fec {
33 namespace code {
34 
35 /*!
36  * \brief POLAR encoder
37  * for basic details see 'polar_common' class.
38  * \ingroup error_coding_blk
39  *
40  * \details
41  * expects values with MSB first. It needs a full information word and encodes it in one
42  * pass. Output is a codeword of block_size.
43  */
44 class FEC_API polar_encoder : public generic_encoder, public polar_common
45 {
46 public:
47     /*!
48      * Factory for a polar code encoder object.
49      *
50      * \param block_size defines the codeword size. It MUST be a
51      *        power of 2.
52      * \param num_info_bits represents the number of information
53      *        bits in a block. Also called frame_size.
54      * \param frozen_bit_positions is an integer vector which
55      *        defines the position of all frozen bits in a block.
56      *        Its size MUST be equal to block_size - num_info_bits.
57      *        Also it must be sorted and every position must only
58      *        occur once.
59      * \param frozen_bit_values holds an unpacked byte for every
60      *        frozen bit position. It defines if a frozen bit is
61      *        fixed to '0' or '1'. Defaults to all ZERO.
62      * \param is_packed choose 1 active bit/byte or 8 active
63      *        bit/byte. if false, VOLK polar encoder is used.
64      */
65     static generic_encoder::sptr make(int block_size,
66                                       int num_info_bits,
67                                       std::vector<int> frozen_bit_positions,
68                                       std::vector<char> frozen_bit_values,
69                                       bool is_packed = false);
70     ~polar_encoder();
71 
72     // FECAPI
73     void generic_work(void* in_buffer, void* out_buffer);
rate()74     double rate() { return (1.0 * get_input_size() / get_output_size()); };
get_input_size()75     int get_input_size() { return num_info_bits() / (d_is_packed ? 8 : 1); };
get_output_size()76     int get_output_size() { return block_size() / (d_is_packed ? 8 : 1); };
set_frame_size(unsigned int frame_size)77     bool set_frame_size(unsigned int frame_size) { return false; };
get_input_conversion()78     const char* get_input_conversion() { return d_is_packed ? "pack" : "none"; };
get_output_conversion()79     const char* get_output_conversion() { return d_is_packed ? "packed_bits" : "none"; };
80 
81 private:
82     polar_encoder(int block_size,
83                   int num_info_bits,
84                   std::vector<int>& frozen_bit_positions,
85                   std::vector<char>& frozen_bit_values,
86                   bool is_packed);
87     bool d_is_packed;
88 
89     // c'tor method for packed algorithm setup.
90     void setup_frozen_bit_inserter();
91 
92     // methods insert input bits and frozen bits into packed array for encoding
93     unsigned char* d_frozen_bit_prototype; // packed frozen bits are written onto it and
94                                            // later copies are used.
95     void insert_packed_frozen_bits_and_reverse(unsigned char* target,
96                                                const unsigned char* input) const;
97     void insert_unpacked_bit_into_packed_array_at_position(unsigned char* target,
98                                                            const unsigned char bit,
99                                                            const int pos) const;
100     void insert_packet_bit_into_packed_array_at_position(unsigned char* target,
101                                                          const unsigned char bit,
102                                                          const int target_pos,
103                                                          const int bit_pos) const;
104 
105     // packed encoding methods
106     void encode_vector_packed(unsigned char* target) const;
107     void encode_vector_packed_subbyte(unsigned char* target) const;
108     void encode_packed_byte(unsigned char* target) const;
109     void encode_vector_packed_interbyte(unsigned char* target) const;
110 };
111 
112 } // namespace code
113 } // namespace fec
114 } // namespace gr
115 
116 #endif /* INCLUDED_FEC_POLAR_ENCODER_H */
117