fec: Merging fecapi with support for CC code.

Original code taken from next branch of Nick McCarthy's fecapi: https://github.com/namccart/fecapi.git Needs: examples, documentation, other tools.
author: Tom Rondeau <tom@trondeau.com> 2014-03-25 10:24:35 -0700
committer: Tom Rondeau <tom@trondeau.com> 2014-05-17 17:45:12 -0400
commit: 6f84515d6290230abeea6c13e1c605746a8a272c (patch)
tree: 9886f55646d94d523f94f1fc3a7921b0ce4baf0c /gr-fec/lib/cc_decoder_impl.cc
parent: 8e5eaa8dbe49973bc808dfe4cead2c91b96cb4c6 (diff)
1 files changed, 505 insertions, 0 deletions
diff --git a/gr-fec/lib/cc_decoder_impl.cc b/gr-fec/lib/cc_decoder_impl.cc
new file mode 100644
index 0000000000..1941306df0
--- /dev/null
+++ b/gr-fec/lib/cc_decoder_impl.cc
@@ -0,0 +1,505 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2013-2014 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "cc_decoder_impl.h"
+#include <math.h>
+#include <boost/assign/list_of.hpp>
+//#include <volk/volk_typedefs.h>
+#include <volk/volk.h>
+#include <sstream>
+#include <stdio.h>
+#include <vector>
+
+namespace gr {
+  namespace fec {
+    namespace code {
+
+      generic_decoder::sptr
+      cc_decoder::make(int framebits, int k,
+                       int rate, std::vector<int> polys,
+                       int start_state, int end_state,
+                       bool tailbiting, bool terminated,
+                       bool truncated, bool streaming)
+      {
+        return generic_decoder::sptr
+          (new cc_decoder_impl(framebits, k, rate, polys,
+                               start_state, end_state,
+                               tailbiting, terminated,
+                               truncated, streaming));
+      }
+
+      cc_decoder_impl::cc_decoder_impl(int framebits, int k,
+                                       int rate, std::vector<int> polys,
+                                       int start_state, int end_state,
+                                       bool tailbiting, bool terminated,
+                                       bool truncated, bool streaming)
+        : generic_decoder("cc_decoder"),
+          d_tailbiting(tailbiting),
+          d_terminated(terminated),
+          d_truncated(truncated),
+          d_streaming(streaming),
+          d_framebits(framebits),
+          d_k(k),
+          d_rate(rate),
+          d_partial_rate(rate),
+          d_polys(polys),
+          d_start_state_chaining(start_state),
+          d_start_state_nonchaining(start_state),
+          d_end_state_nonchaining(end_state)
+      {
+        d_vp = new struct v;
+
+        d_numstates = 1 << (d_k - 1);
+
+        d_decision_t_size = d_numstates/8; //packed bit array
+
+        if(d_tailbiting) {
+          d_end_state = &d_end_state_chaining;
+          d_veclen = d_framebits + (6 * (d_k - 1));
+          if(posix_memalign((void**)&d_managed_in, 16, d_veclen * d_rate * sizeof(COMPUTETYPE))) {
+            printf("allocation failed\n");
+            exit(1);
+          }
+        }
+        /*
+        else if(d_trunc_intrinsic) {
+          d_end_state = &d_end_state_nonchaining;
+          d_veclen = d_framebits + d_k - 1;
+          if(posix_memalign((void**)&d_managed_in, 16, d_veclen * d_rate * sizeof(COMPUTETYPE))){
+            printf("allocation failed\n");
+            exit(1);
+          }
+          int cnt = 0;
+          for(int i = 0; i < d_rate; ++i) {
+            if (d_polys[i] != 1) {
+              cnt++;
+            }
+          }
+          d_partial_rate = cnt;
+        }
+        */
+        else if(d_truncated) {
+          d_end_state = &d_end_state_chaining;
+          d_veclen = d_framebits;
+        }
+        else if(d_terminated) {
+          d_end_state = (end_state == -1) ? &d_end_state_chaining : &d_end_state_nonchaining;
+          d_veclen = d_framebits + d_k - 1;
+        }
+
+        //streaming
+        else {
+          d_end_state = &d_end_state_chaining;
+          d_veclen = d_framebits + d_k - 1;
+        }
+
+        if(posix_memalign((void**)&d_vp->metrics, 16, 2 * d_numstates * sizeof(COMPUTETYPE))) {
+          printf("allocation failed\n");
+          exit(1);
+        }
+
+        d_vp->metrics1.t = d_vp->metrics;
+        d_vp->metrics2.t = d_vp->metrics + d_numstates;
+
+        if(posix_memalign((void**)&d_vp->decisions, 16,d_veclen*d_decision_t_size)) {
+          printf("allocation failed\n");
+          exit(1);
+        }
+
+        if(posix_memalign((void**)&Branchtab, 16, sizeof(COMPUTETYPE) * d_numstates/2*rate)) {
+          printf("allocation failed\n");
+          exit(1);
+        }
+
+        create_viterbi();
+
+        if(d_k-1<8) {
+          d_ADDSHIFT = (8-(d_k-1));
+          d_SUBSHIFT =  0;
+        }
+        else if(d_k-1>8) {
+          d_ADDSHIFT = 0;
+          d_SUBSHIFT =  ((d_k-1)-8);
+        }
+        else {
+          d_ADDSHIFT = 0;
+          d_SUBSHIFT = 0;
+        }
+
+        yp_kernel = boost::assign::map_list_of("k=7r=2", volk_8u_x4_conv_k7_r2_8u);
+
+        std::string k_ = "k=";
+        std::string r_ = "r=";
+
+        std::ostringstream kerneltype;
+        kerneltype << k_ << d_k << r_ << d_rate;
+
+        d_kernel = yp_kernel[kerneltype.str()];
+      }
+
+      cc_decoder_impl::~cc_decoder_impl()
+      {
+        free(d_vp->decisions);
+        free(Branchtab);
+        free(d_vp->metrics);
+      }
+
+      int
+      cc_decoder_impl::get_output_size()
+      {
+        //unpacked bits
+        return d_framebits;
+      }
+
+      int
+      cc_decoder_impl::get_input_size()
+      {
+        if(d_terminated) {
+          return d_rate * (d_framebits + d_k - 1);
+        }
+        /*
+        else if(d_trunc_intrinsic) {
+          int cnt = 0;
+          for(int i = 0; i < d_rate; ++i) {
+            if (d_polys[i] != 1) {
+              cnt++;
+            }
+          }
+          return (d_rate * (d_framebits)) + (cnt * (d_k - 1));
+        }
+        */
+        else {
+          return d_rate * d_framebits;
+        }
+      }
+
+      int
+      cc_decoder_impl::get_input_item_size()
+      {
+        return 1;
+      }
+
+      int
+      cc_decoder_impl::get_history()
+      {
+        if(d_streaming) {
+          return d_rate * (d_k - 1);
+        }
+        else {
+          return 0;
+        }
+      }
+
+      /*const char* cc_decoder_impl::get_output_conversion() {
+        return "unpack";
+        }*/
+
+      float
+      cc_decoder_impl::get_shift()
+      {
+        return 128.0;
+      }
+
+      const char*
+      cc_decoder_impl::get_conversion()
+      {
+        return "uchar";
+      }
+
+      void
+      cc_decoder_impl::create_viterbi()
+      {
+        int state;
+        unsigned int i;
+        partab_init();
+        for(state = 0; state < d_numstates/2; state++) {
+          for(i = 0; i < d_rate; i++) {
+            Branchtab[i*d_numstates/2+state] = (d_polys[i] < 0) ^ parity((2*state) & abs(d_polys[i])) ? 255 : 0;
+          }
+        }
+
+        if(d_streaming) {
+          //printf("streaming\n");
+          d_start_state = &d_start_state_chaining;
+          init_viterbi_unbiased(d_vp);
+        }
+        else if(d_tailbiting) {
+          //printf("tailbiting\n");
+          d_start_state = &d_start_state_nonchaining;
+          init_viterbi_unbiased(d_vp);
+        }
+        else {
+          //printf("other!\n");
+          d_start_state = &d_start_state_nonchaining;
+          init_viterbi(d_vp, *d_start_state);
+        }
+
+        return;
+      }
+
+      int
+      cc_decoder_impl::parity(int x)
+      {
+        x ^= (x >> 16);
+        x ^= (x >> 8);
+        return parityb(x);
+      }
+
+      int
+      cc_decoder_impl::parityb(unsigned char x)
+      {
+        return Partab[x];
+      }
+
+      void
+      cc_decoder_impl::partab_init(void)
+      {
+        int i,cnt,ti;
+
+        /* Initialize parity lookup table */
+        for(i=0;i<256;i++){
+          cnt = 0;
+          ti = i;
+          while(ti){
+            if(ti & 1)
+              cnt++;
+            ti >>= 1;
+          }
+          Partab[i] = cnt & 1;
+        }
+      }
+
+      int
+      cc_decoder_impl::init_viterbi(struct v* vp, int starting_state)
+      {
+        int i;
+
+        if(vp == NULL)
+          return -1;
+        for(i = 0; i < d_numstates; i++) {
+          vp->metrics1.t[i] = 63;
+        }
+
+        vp->old_metrics = vp->metrics1;
+        vp->new_metrics = vp->metrics2;
+        vp->old_metrics.t[starting_state & (d_numstates-1)] = 0; /* Bias known start state */
+        return 0;
+      }
+
+      int
+      cc_decoder_impl::init_viterbi_unbiased(struct v* vp)
+      {
+        int i;
+
+        if(vp == NULL)
+          return -1;
+        for(i=0;i<d_numstates;i++)
+          vp->metrics1.t[i] = 31;
+
+        vp->old_metrics = vp->metrics1;
+        vp->new_metrics = vp->metrics2;
+        //no bias step
+        return 0;
+      }
+
+      int
+      cc_decoder_impl::find_endstate()
+      {
+        COMPUTETYPE* met = (d_k%2 == 0)? d_vp->new_metrics.t : d_vp->old_metrics.t;
+        COMPUTETYPE min = met[0];
+        int state = 0;
+        for(int i = 1; i < d_numstates; ++i) {
+          if(met[i] < min) {
+            min = met[i];
+            state = i;
+          }
+        }
+        return state;
+      }
+
+      int
+      cc_decoder_impl::update_viterbi_blk(const COMPUTETYPE* syms, int nbits)
+      {
+        DECISIONTYPE *d;
+
+        d = d_vp->decisions;
+        //going to have to use nbits for tailbiting?
+        //memset(d,0,d_decision_t_size * (d_framebits+d_k-1));//use volk here?
+        memset(d,0,d_decision_t_size * nbits);//use volk here?
+
+        //d_kernel( d_vp->new_metrics.t, d_vp->old_metrics.t, syms, d, d_framebits, d_k - 1, Branchtab);
+        d_kernel( d_vp->new_metrics.t, d_vp->old_metrics.t, syms, d, nbits - (d_k - 1), d_k -1, Branchtab);
+
+        return 0;
+      }
+
+      int
+      cc_decoder_impl::chainback_viterbi(DECISIONTYPE* data,
+                                         unsigned int nbits,
+                                         unsigned int endstate,
+                                         unsigned int tailsize)
+      {
+        DECISIONTYPE *d;
+
+        /* ADDSHIFT and SUBSHIFT make sure that the thing returned is a byte. */
+        d = d_vp->decisions;
+        /* Make room beyond the end of the encoder register so we can
+         * accumulate a full byte of decoded data
+         */
+
+        endstate = (endstate%d_numstates) << d_ADDSHIFT;
+
+        /* The store into data[] only needs to be done every 8 bits.
+         * But this avoids a conditional branch, and the writes will
+         * combine in the cache anyway
+         */
+
+        d += tailsize * d_decision_t_size ; /* Look past tail */
+        int retval;
+        int dif = tailsize - (d_k - 1);
+        //printf("break, %d, %d\n", dif, (nbits+dif)%d_framebits);
+        decision_t dec;
+        while(nbits-- > d_framebits - (d_k - 1)) {
+          int k;
+          dec.t = &d[nbits * d_decision_t_size];
+          k = (dec.w[(endstate>>d_ADDSHIFT)/32] >> ((endstate>>d_ADDSHIFT)%32)) & 1;
+
+          endstate = (endstate >> 1) | (k << (d_k-2+d_ADDSHIFT));
+          //data[((nbits+dif)%nbits)>>3] = endstate>>d_SUBSHIFT;
+          //printf("%d, %d\n", k, (nbits+dif)%d_framebits);
+          data[((nbits+dif)%d_framebits)] = k;
+
+          retval = endstate;
+        }
+        nbits += 1;
+
+        while(nbits-- != 0) {
+          int k;
+
+          dec.t = &d[nbits * d_decision_t_size];
+
+          k = (dec.w[(endstate>>d_ADDSHIFT)/32] >> ((endstate>>d_ADDSHIFT)%32)) & 1;
+
+          endstate = (endstate >> 1) | (k << (d_k-2+d_ADDSHIFT));
+          data[((nbits+dif)%d_framebits)] = k;
+        }
+        //printf("%d, %d, %d, %d, %d, %d, %d, %d\n", data[4095],data[4094],data[4093],data[4092],data[4091],data[4090],data[4089],data[4088]);
+        return retval >> d_ADDSHIFT;
+      }
+
+      void
+      cc_decoder_impl::set_framebits(int framebits)
+      {
+        d_framebits = framebits;
+        if(d_tailbiting) {
+          d_veclen = d_framebits + (6 * (d_k - 1));
+        }
+        else if(d_truncated) {
+          d_veclen = d_framebits;
+        }
+        else {
+          d_veclen = d_framebits + d_k - 1;
+        }
+      }
+
+      void
+      cc_decoder_impl::generic_work(void *inBuffer, void *outBuffer)
+      {
+        const COMPUTETYPE *in = (const COMPUTETYPE *) inBuffer;
+        DECISIONTYPE *out = (DECISIONTYPE *) outBuffer;
+
+        if(d_tailbiting) {
+          memcpy(d_managed_in, in, d_framebits * d_rate * sizeof(COMPUTETYPE));
+          memcpy(d_managed_in + d_framebits * d_rate * sizeof(COMPUTETYPE), in,
+                 (d_veclen - d_framebits) * d_rate * sizeof(COMPUTETYPE));
+          /*for(int i = 0; i < d_veclen * d_rate; ++i) {
+            printf("%u...%d\n", d_managed_in[i], i);
+            }*/
+          update_viterbi_blk(d_managed_in, d_veclen);
+          d_end_state_chaining = find_endstate();
+          chainback_viterbi(&out[0], d_framebits, *d_end_state, d_veclen - d_framebits);
+          init_viterbi_unbiased(d_vp);
+        }
+
+        /*
+        else if(d_trunc_intrinsic) {
+          memcpy(d_managed_in, in, d_framebits * d_rate * sizeof(COMPUTETYPE));
+          for(int i = 0; i < (d_k - 1); ++i) {
+            int cnt = 0;
+            for(int j = 0; j < d_rate; ++j) {
+              if(d_polys[j] != 1) {
+
+                d_managed_in[(d_framebits * d_rate) + (i * d_rate) + j] =
+                  in[(d_framebits * d_rate) + (i * d_partial_rate) + cnt++];
+              }
+              else {
+
+                d_managed_in[(d_framebits * d_rate) + (i * d_rate) + j] =
+                  (((*d_end_state) >> (d_k - 2 - i)) & 1) * ((1 << (sizeof(COMPUTETYPE) * 8)) - 1);
+              }
+            }
+          }
+          update_viterbi_blk(d_managed_in, d_veclen);
+          d_end_state_chaining = find_endstate();
+          chainback_viterbi(&out[0], d_framebits, *d_end_state, d_veclen - d_framebits);
+          init_viterbi(d_vp, *d_start_state);
+        }
+        */
+
+        else if(d_truncated) {
+          update_viterbi_blk(&in[0], d_veclen);
+          d_end_state_chaining = find_endstate();
+          //printf("...end %d\n", d_end_state_chaining);
+          for(unsigned int i = 0; i < d_k-1; ++i) {
+            out[d_veclen - 1 - i] = ((*d_end_state) >> i) & 1;
+          }
+          d_start_state_chaining = chainback_viterbi(&out[0], d_framebits - (d_k - 1),
+                                                     *d_end_state, d_k - 1);
+          init_viterbi(d_vp, *d_start_state);
+          /*for(int i = d_framebits - 25; i < d_framebits; ++i) {
+          //for(int i = 0; i < 25; ++i) {
+          printf("%u... : %u\n", out[i], i);
+          }*/
+        }
+        //terminated or streaming
+        else {
+          update_viterbi_blk(&in[0], d_veclen);
+          d_end_state_chaining = find_endstate();
+          //printf("es: %d\n", d_end_state_chaining);
+          d_start_state_chaining = chainback_viterbi(&out[0], d_framebits, *d_end_state,
+                                                     d_veclen - d_framebits);
+
+          init_viterbi(d_vp, *d_start_state);
+          /*for(int i = d_framebits * d_rate - 25; i < d_framebits * d_rate; ++i) {
+            printf("%u... : %u\n", in[i], i);
+            }*/
+        }
+      }
+
+    } /* namespace code */
+  } /* namespace fec */
+} /* namespace gr */
+
author	Tom Rondeau <tom@trondeau.com>	2014-03-25 10:24:35 -0700
committer	Tom Rondeau <tom@trondeau.com>	2014-05-17 17:45:12 -0400
commit	6f84515d6290230abeea6c13e1c605746a8a272c (patch)
tree	9886f55646d94d523f94f1fc3a7921b0ce4baf0c /gr-fec/lib/cc_decoder_impl.cc
parent	8e5eaa8dbe49973bc808dfe4cead2c91b96cb4c6 (diff)