1 files changed, 93 insertions, 0 deletions
diff --git a/gr-blocks/lib/skiphead_impl.cc b/gr-blocks/lib/skiphead_impl.cc
new file mode 100644
index 0000000000..feb39eb8f4
--- /dev/null
+++ b/gr-blocks/lib/skiphead_impl.cc
@@ -0,0 +1,93 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2005,2007,2010,2013 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 "skiphead_impl.h"
+#include <gr_io_signature.h>
+#include <string.h>
+
+namespace gr {
+  namespace blocks {
+
+    skiphead::sptr
+    skiphead::make(size_t itemsize, uint64_t nitems_to_skip)
+    {
+      return gnuradio::get_initial_sptr
+        (new skiphead_impl(itemsize, nitems_to_skip));
+    }
+
+    skiphead_impl::skiphead_impl(size_t itemsize, uint64_t nitems_to_skip)
+      : gr_block("skiphead",
+                 gr_make_io_signature(1, 1, itemsize),
+                 gr_make_io_signature(1, 1, itemsize)),
+        d_nitems_to_skip(nitems_to_skip), d_nitems(0)
+    {
+    }
+
+    skiphead_impl::~skiphead_impl()
+    {
+    }
+
+    int
+    skiphead_impl::general_work(int noutput_items,
+                                gr_vector_int &ninput_items_,
+                                gr_vector_const_void_star &input_items,
+                                gr_vector_void_star &output_items)
+    {
+      const char *in = (const char*)input_items[0];
+      char *out = (char*)output_items[0];
+
+      int ninput_items = std::min(ninput_items_[0], noutput_items);
+      int ii = 0;			// input index
+
+      while (ii < ninput_items) {
+        uint64_t ni_total = ii + d_nitems;  	// total items processed so far
+        if(ni_total < d_nitems_to_skip) {	// need to skip some more
+
+          int n_to_skip = (int)std::min(d_nitems_to_skip - ni_total,
+                                        (uint64_t)(ninput_items - ii));
+          ii += n_to_skip;
+        }
+
+        else {		// nothing left to skip.  copy away
+          int n_to_copy = ninput_items - ii;
+          if(n_to_copy > 0) {
+            size_t itemsize = output_signature()->sizeof_stream_item(0);
+            memcpy(out, in + (ii*itemsize), n_to_copy*itemsize);
+          }
+
+          d_nitems += ninput_items;
+          consume_each(ninput_items);
+          return n_to_copy;
+        }
+      }
+
+      d_nitems += ninput_items;
+      consume_each(ninput_items);
+      return 0;
+    }
+
+  } /* namespace blocks */
+} /* namespace gr */