3 files changed, 40 insertions, 1 deletions
diff --git a/gr-blocks/lib/skiphead_impl.cc b/gr-blocks/lib/skiphead_impl.cc
index da9cb11280..0a1685b732 100644
--- a/gr-blocks/lib/skiphead_impl.cc
+++ b/gr-blocks/lib/skiphead_impl.cc
@@ -44,6 +44,12 @@ namespace gr {
                  io_signature::make(1, 1, itemsize)),
         d_nitems_to_skip(nitems_to_skip), d_nitems(0)
     {
+      // Reserve space for a few tags to avoid constant re-allocation
+      // in the call to get_tags_in_window
+      d_tags.reserve(8);
+
+      // We'll handle propagating tags our selves to handle shifting offsets of tags
+      set_tag_propagation_policy(TPP_DONT);
     }
 
     skiphead_impl::~skiphead_impl()
@@ -71,7 +77,13 @@ namespace gr {
           ii += n_to_skip;
         }
 
-        else {		// nothing left to skip.  copy away
+        else { // nothing left to skip. copy away
+          // Grab all tags in the window and shift their offsets appropriately
+          get_tags_in_window(d_tags, 0, ii, ninput_items);
+          for(std::vector<tag_t>::iterator it = d_tags.begin(); it != d_tags.end(); it++) {
+            (*it).offset -= d_nitems_to_skip;
+            add_item_tag(0, *it);
+          }
           int n_to_copy = ninput_items - ii;
           if(n_to_copy > 0) {
             size_t itemsize = output_signature()->sizeof_stream_item(0);
diff --git a/gr-blocks/lib/skiphead_impl.h b/gr-blocks/lib/skiphead_impl.h
index db4df50adb..738fa86a61 100644
--- a/gr-blocks/lib/skiphead_impl.h
+++ b/gr-blocks/lib/skiphead_impl.h
@@ -33,6 +33,7 @@ namespace gr {
     private:
       uint64_t d_nitems_to_skip;
       uint64_t d_nitems;           // total items seen
+      std::vector<tag_t> d_tags;
 
     public:
       skiphead_impl(size_t itemsize, uint64_t nitems_to_skip);
diff --git a/gr-blocks/python/blocks/qa_skiphead.py b/gr-blocks/python/blocks/qa_skiphead.py
index a9b6df40cf..098e7b1e94 100755
--- a/gr-blocks/python/blocks/qa_skiphead.py
+++ b/gr-blocks/python/blocks/qa_skiphead.py
@@ -21,6 +21,19 @@
 #
 
 from gnuradio import gr, gr_unittest, blocks
+import pmt
+import numpy
+
+
+def make_tag(key, value, offset, srcid=None):
+    tag = gr.tag_t()
+    tag.key = pmt.string_to_symbol(key)
+    tag.value = pmt.to_pmt(value)
+    tag.offset = offset
+    if srcid is not None:
+        tag.srcid = pmt.to_pmt(srcid)
+    return tag
+
 
 class test_skiphead(gr_unittest.TestCase):
 
@@ -97,6 +110,19 @@ class test_skiphead(gr_unittest.TestCase):
         dst_data = dst1.data()
         self.assertEqual(expected_result, dst_data)
 
+    def test_skip_tags(self):
+        skip_cnt = 25
+        expected_result = tuple(self.src_data[skip_cnt:])
+
+        src_tags = tuple([make_tag('foo', 'bar', 50, 'src')])
+        src1 = blocks.vector_source_i(self.src_data, tags=src_tags)
+        op = blocks.skiphead(gr.sizeof_int, skip_cnt)
+        dst1 = blocks.vector_sink_i()
+        self.tb.connect(src1, op, dst1)
+        self.tb.run()
+        dst_data = dst1.data()
+        self.assertEqual(expected_result, dst_data)
+        self.assertEqual(dst1.tags()[0].offset, 25, "Tag offset is incorrect")
 
 if __name__ == '__main__':
     gr_unittest.run(test_skiphead, "test_skiphead.xml")