1 files changed, 75 insertions, 0 deletions
diff --git a/gr-blocks/lib/head_impl.cc b/gr-blocks/lib/head_impl.cc
new file mode 100644
index 0000000000..7dfa36607c
--- /dev/null
+++ b/gr-blocks/lib/head_impl.cc
@@ -0,0 +1,75 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2004,2009,2013 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 "head_impl.h"
+#include <gr_io_signature.h>
+#include <string.h>
+
+namespace gr {
+  namespace blocks {
+
+    head::sptr
+    head::make(size_t sizeof_stream_item, uint64_t nitems)
+    {
+      return gnuradio::get_initial_sptr
+        (new head_impl(sizeof_stream_item, nitems));
+    }
+
+    head_impl::head_impl(size_t sizeof_stream_item, uint64_t nitems)
+      : gr_sync_block("head",
+                      gr_make_io_signature(1, 1, sizeof_stream_item),
+                      gr_make_io_signature(1, 1, sizeof_stream_item)),
+        d_nitems(nitems), d_ncopied_items(0)
+    {
+    }
+
+    head_impl::~head_impl()
+    {
+    }
+
+    int
+    head_impl::work(int noutput_items,
+                    gr_vector_const_void_star &input_items,
+		    gr_vector_void_star &output_items)
+    {
+      if(d_ncopied_items >= d_nitems)
+        return -1;			// Done!
+
+      unsigned n = std::min(d_nitems - d_ncopied_items,
+                            (uint64_t)noutput_items);
+
+      if(n == 0)
+        return 0;
+
+      memcpy(output_items[0], input_items[0],
+             n * input_signature()->sizeof_stream_item (0));
+      d_ncopied_items += n;
+
+      return n;
+    }
+
+  } /* namespace blocks */
+} /* namespace gr */