From ac8ef5f69a69f11fd202470da68709cd3006d547 Mon Sep 17 00:00:00 2001 From: Nao Pross Date: Fri, 19 Nov 2021 21:29:45 +0100 Subject: Frames --- src/gr-fadingui/python/frame_obj.py | 74 +++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 src/gr-fadingui/python/frame_obj.py (limited to 'src/gr-fadingui/python/frame_obj.py') diff --git a/src/gr-fadingui/python/frame_obj.py b/src/gr-fadingui/python/frame_obj.py new file mode 100644 index 0000000..b9dae70 --- /dev/null +++ b/src/gr-fadingui/python/frame_obj.py @@ -0,0 +1,74 @@ +#!/usr/bin/env python +# -*- coding: utf-8 -*- +# +# Copyright 2021 Naoki Pross. + +from functools import reduce +import operator as op + +import numpy as np +from gnuradio import gr + + +class frame_obj(gr.basic_block): + """ + Frame Object: Contains informations about a data frame. + + ------------------------------------------------------------------------------- + | Preamble | Padding | ID | Data Length | Parity | Payload | Padding | + | k bytes | 1 bit | 4 bits | 22 bits | 5 bits | | if necessary | + ------------------------------------------------------------------------------- + | (31, 26) Hamming code EC | + ----------------------------------- + + - The preamble is user defined. + - The ID (11 bits) + Data length (22 bits) together are a 31 bits, followed + by 26 parity bits computed using a (31,26) hamming code. + + This constraints the maximum payload size to 64 MB and the number IDs to + 1024 (i.e. max file size is 1 GB, more than enough for many thing) + + """ + def __init__(self, preamble, payload_len): + gr.basic_block.__init__(self, name="frame_obj", + in_sig=None, out_sig=None) + + self.preamble = np.array(preamble, dtype=np.uint8) + + self.preamble_len = len(self.preamble) + self.payload_len = payload_len + + @property + def length(self): + """Frame lenght in bytes""" + return self.preamble_len + self.payload_len + 8 + + def parity(self, bits): + """Compute the 5 parity bits for an unpacked array of 26 bits""" + assert(len(bits) == 26) + # FIXME: does not work + # gen = np.array( + # [[1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0], + # [0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1], + # [0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0], + # [0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0], + # [0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1]], + # dtype=np.uint8) + # return np.matmul(bits, gen) % 2 + return np.array([0, 0, 0, 0, 0]) + + def make(self, idv, data_len, data): + """Make a frame""" + return np.concatenate(self.preamble, np.packbits(hamming), data) + + def syndrome(self, bits): + """Compute the syndrome (check Hamming code) for an unpacked array of 31 bits""" + assert(len(bits) == 31) + return reduce(op.xor, [i for i, bit in enumerate(bits) if bit]) + + def general_work(self, input_items, output_items): + """ + This block has no inputs or output + """ + return 0; + -- cgit v1.2.1