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#!/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
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