1 files changed, 83 insertions, 0 deletions
diff --git a/gnuradio-core/src/lib/general/gr_skiphead.cc b/gnuradio-core/src/lib/general/gr_skiphead.cc
new file mode 100644
index 000000000..7b441bea9
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_skiphead.cc
@@ -0,0 +1,83 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2005,2007,2010 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 <gr_skiphead.h>
+#include <gr_io_signature.h>
+#include <string.h>
+
+gr_skiphead::gr_skiphead (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)
+{
+}
+
+gr_skiphead_sptr
+gr_make_skiphead (size_t itemsize, uint64_t nitems_to_skip)
+{
+  return gnuradio::get_initial_sptr(new gr_skiphead (itemsize, nitems_to_skip));
+}
+
+int
+gr_skiphead::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;
+}