epy_block_0.py

"""
Tag Rewrite
"""

import numpy as np
from gnuradio import gr
import pmt

log = gr.logger("TR")
log.set_level("DEBUG")

class blk(gr.sync_block):  # other base classes are basic_block, decim_block, interp_block
    """TagRewrite - rewrite tag to any value"""

    def __init__(self, tag_name="", tag_value=1):  # only default arguments here
        """arguments to this function show up as parameters in GRC"""
        gr.sync_block.__init__(
            self,
            name='Tag Rewrite',   # will show up in GRC
            in_sig=[np.byte],
            out_sig=[np.byte]
        )
        # if an attribute with the same name as a parameter is found,
        # a callback is registered (properties work, too).
        self.tag_name = pmt.intern(tag_name)
        self.tag_value = pmt.intern(str(tag_value))

        # pass through tags
        self.set_tag_propagation_policy(gr.TPP_DONT)

        log.debug("TR init done")

    def work(self, input_items, output_items):
        """Update tag value"""
        output_items[0][:] = input_items[0]

        nr = len(input_items[0])
        tags = self.get_tags_in_window(0, 0, nr, self.tag_name)
        for tag in tags:
            self.add_item_tag(0, tag.offset, self.tag_name, self.tag_value)

        return len(output_items[0])