Merged r4518:5130 from developer branch n4hy/ofdm into trunk, passes distcheck.

[debian/gnuradio] / gnuradio-core / src / lib / general / gr_ofdm_sampler.cc

diff --git a/gnuradio-core/src/lib/general/gr_ofdm_sampler.cc b/gnuradio-core/src/lib/general/gr_ofdm_sampler.cc
new file mode 100644 (file)
index 0000000..9ac5abd
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_ofdm_sampler.cc
@@ -0,0 +1,94 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2007 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 2, 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 <gr_ofdm_sampler.h>
+#include <gr_io_signature.h>
+#include <gr_expj.h>
+
+gr_ofdm_sampler_sptr
+gr_make_ofdm_sampler (unsigned int fft_length, 
+                     unsigned int symbol_length)
+{
+  return gr_ofdm_sampler_sptr (new gr_ofdm_sampler (fft_length, symbol_length));
+}
+
+gr_ofdm_sampler::gr_ofdm_sampler (unsigned int fft_length, 
+                                 unsigned int symbol_length)
+  : gr_block ("ofdm_sampler",
+             gr_make_io_signature (2, 2, sizeof (gr_complex)),
+             gr_make_io_signature (1, 1, sizeof (gr_complex)*fft_length)),
+    d_fft_length(fft_length), d_symbol_length(symbol_length)
+{
+}
+
+void
+gr_ofdm_sampler::forecast (int noutput_items, gr_vector_int &ninput_items_required)
+{
+  // FIXME do we need more
+  int nreqd  = (noutput_items-1) * d_symbol_length + d_fft_length;
+  unsigned ninputs = ninput_items_required.size ();
+  for (unsigned i = 0; i < ninputs; i++)
+    ninput_items_required[i] = nreqd;
+}
+
+int
+gr_ofdm_sampler::general_work (int noutput_items,
+                              gr_vector_int &ninput_items,
+                              gr_vector_const_void_star &input_items,
+                              gr_vector_void_star &output_items)
+{
+  gr_complex *iptr = (gr_complex *) input_items[0];
+  gr_complex *trigger = (gr_complex *) input_items[1];
+
+  gr_complex *optr = (gr_complex *) output_items[0];
+
+  int found=0;
+
+  unsigned int i=d_fft_length-1;
+
+  while(!found && i<std::min(ninput_items[0],ninput_items[1]) )
+    if(trigger[i].real() > 0.5)
+      found = 1;
+    else
+      i++;
+
+  if(found) {
+    assert(i-d_fft_length+1 >= 0);
+    for(unsigned int j=i-d_fft_length+1;j<=i;j++)
+      *optr++ = iptr[j];
+    consume_each(i-d_fft_length+2);
+    //printf("OFDM Sampler found:  ninput_items: %d/%d   noutput_items: %d  consumed: %d   found: %d\n", 
+    //   ninput_items[0], ninput_items[1], noutput_items, (i-d_fft_length+2), found);
+  }
+  else {
+    consume_each(i-d_fft_length+1);
+    //printf("OFDM Sampler not found:  ninput_items: %d/%d   noutput_items: %d  consumed: %d   found: %d\n", 
+    //  ninput_items[0], ninput_items[1], noutput_items, (i-d_fft_length+1), found);
+ }
+
+
+  return found;
+}