1 files changed, 137 insertions, 0 deletions
diff --git a/gnuradio-runtime/python/gnuradio/gr/packet_utils.py b/gnuradio-runtime/python/gnuradio/gr/packet_utils.py
new file mode 100644
index 0000000000..7ae42e88e3
--- /dev/null
+++ b/gnuradio-runtime/python/gnuradio/gr/packet_utils.py
@@ -0,0 +1,137 @@
+#!/usr/bin/env python
+#
+# Copyright 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.
+# 
+
+from gnuradio import gr
+import pmt
+
+def make_lengthtags(lengths, offsets, tagname='length', vlen=1):
+    tags = []
+    assert(len(offsets) == len(lengths))
+    for offset, length in zip(offsets, lengths):
+        tag = gr.tag_t()
+        tag.offset = offset/vlen
+        tag.key = pmt.string_to_symbol(tagname)
+        tag.value = pmt.from_long(length/vlen)
+        tags.append(tag)
+    return tags
+
+def string_to_vector(string):
+    v = []
+    for s in string:
+        v.append(ord(s))
+    return v
+
+def strings_to_vectors(strings, tsb_tag_key):
+    vs = [string_to_vector(string) for string in strings]
+    return packets_to_vectors(vs, tsb_tag_key)
+
+def vector_to_string(v):
+    s = []
+    for d in v:
+        s.append(chr(d))
+    return ''.join(s)
+
+def vectors_to_strings(data, tags, tsb_tag_key):
+    packets = vectors_to_packets(data, tags, tsb_tag_key)
+    return [vector_to_string(packet) for packet in packets]
+
+def count_bursts(data, tags, tsb_tag_key, vlen=1):
+    lengthtags = [t for t in tags
+                  if pmt.symbol_to_string(t.key) == tsb_tag_key]
+    lengths = {}
+    for tag in lengthtags:
+        if tag.offset in lengths:
+            raise ValueError(
+                "More than one tags with key {0} with the same offset={1}."
+                .format(tsb_tag_key, tag.offset))
+        lengths[tag.offset] = pmt.to_long(tag.value)*vlen
+    in_burst = False
+    in_packet = False
+    packet_length = None
+    packet_pos = None
+    burst_count = 0
+    for pos in range(len(data)):
+        if pos in lengths:
+            if in_packet:
+                print("Got tag at pos {0} current packet_pos is {1}".format(pos, packet_pos))
+                raise StandardError("Received packet tag while in packet.")
+            packet_pos = -1
+            packet_length = lengths[pos]
+            in_packet = True
+            if not in_burst:
+                burst_count += 1
+            in_burst = True
+        elif not in_packet:
+            in_burst = False
+        if in_packet:
+            packet_pos += 1
+            if packet_pos == packet_length-1:
+                in_packet = False
+                packet_pos = None
+    return burst_count
+
+def vectors_to_packets(data, tags, tsb_tag_key, vlen=1):
+    lengthtags = [t for t in tags
+                  if pmt.symbol_to_string(t.key) == tsb_tag_key]
+    lengths = {}
+    for tag in lengthtags:
+        if tag.offset in lengths:
+            raise ValueError(
+                "More than one tags with key {0} with the same offset={1}."
+                .format(tsb_tag_key, tag.offset))
+        lengths[tag.offset] = pmt.to_long(tag.value)*vlen
+    if 0 not in lengths:
+        raise ValueError("There is no tag with key {0} and an offset of 0"
+                         .format(tsb_tag_key))
+    pos = 0
+    packets = []
+    while pos < len(data):
+        if pos not in lengths:
+            raise ValueError("There is no tag with key {0} and an offset of {1}."
+                             "We were expecting one."
+                             .format(tsb_tag_key, pos))
+        length = lengths[pos]
+        if length == 0:
+            raise ValueError("Packets cannot have zero length.")
+        if pos+length > len(data):
+            raise ValueError("The final packet is incomplete.")
+        packets.append(data[pos: pos+length])
+        pos += length
+    return packets
+
+def packets_to_vectors(packets, tsb_tag_key, vlen=1):
+    """ Returns a single data vector and a set of tags.
+    If used with blocks.vector_source_X, this set of data
+    and tags will produced a correct tagged stream. """
+    tags = []
+    data = []
+    offset = 0
+    for packet in packets:
+        data.extend(packet)
+        tag = gr.tag_t()
+        tag.offset = offset/vlen
+        tag.key = pmt.string_to_symbol(tsb_tag_key)
+        tag.value = pmt.from_long(len(packet)/vlen)
+        tags.append(tag)
+        offset = offset + len(packet)
+    return data, tags
+