Source code for bitmath.integrations

# -*- coding: utf-8 -*-
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# Copyright © 2014-2016 Tim Bielawa <timbielawa@gmail.com>
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import bitmath
import argparse
import progressbar.widgets

######################################################################
# Integrations with 3rd party modules
[docs]def BitmathType(bmstring): """An 'argument type' for integrations with the argparse module. For more information, see https://docs.python.org/2/library/argparse.html#type Of particular interest to us is this bit: ``type=`` can take any callable that takes a single string argument and returns the converted value I.e., ``type`` can be a function (such as this function) or a class which implements the ``__call__`` method. Example usage of the bitmath.BitmathType argparser type: >>> import bitmath >>> import argparse >>> parser = argparse.ArgumentParser() >>> parser.add_argument("--file-size", type=bitmath.BitmathType) >>> parser.parse_args("--file-size 1337MiB".split()) Namespace(file_size=MiB(1337.0)) Invalid usage includes any input that the bitmath.parse_string function already rejects. Additionally, **UNQUOTED** arguments with spaces in them are rejected (shlex.split used in the following examples to conserve single quotes in the parse_args call): >>> parser = argparse.ArgumentParser() >>> parser.add_argument("--file-size", type=bitmath.BitmathType) >>> import shlex >>> # The following is ACCEPTABLE USAGE: ... >>> parser.parse_args(shlex.split("--file-size '1337 MiB'")) Namespace(file_size=MiB(1337.0)) >>> # The following is INCORRECT USAGE because the string "1337 MiB" is not quoted! ... >>> parser.parse_args(shlex.split("--file-size 1337 MiB")) error: argument --file-size: 1337 can not be parsed into a valid bitmath object """ try: argvalue = bitmath.parse_string(bmstring) except ValueError: raise argparse.ArgumentTypeError("'%s' can not be parsed into a valid bitmath object" % bmstring) else: return argvalue
###################################################################### # Speed widget for integration with the Progress bar module
[docs]class BitmathFileTransferSpeed(progressbar.widgets.Widget): """Widget for showing the transfer speed (useful for file transfers).""" __slots__ = ('system', 'format') def __init__(self, system=bitmath.NIST, format="{value:.2f} {unit}/s"): self.system = system self.format = format def update(self, pbar): """Updates the widget with the current NIST/SI speed. Basically, this calculates the average rate of update and figures out how to make a "pretty" prefix unit""" if pbar.seconds_elapsed < 2e-6 or pbar.currval < 2e-6: scaled = bitmath.Byte() else: speed = pbar.currval / pbar.seconds_elapsed scaled = bitmath.Byte(speed).best_prefix(system=self.system) return scaled.format(self.format)