1#!/usr/bin/env python3
2
3# ################################################################
4# Copyright (c) 2018-2020, Facebook, Inc.
5# All rights reserved.
6#
7# This source code is licensed under both the BSD-style license (found in the
8# LICENSE file in the root directory of this source tree) and the GPLv2 (found
9# in the COPYING file in the root directory of this source tree).
10# You may select, at your option, one of the above-listed licenses.
11# ##########################################################################
12
13# Rate limiter, replacement for pv
14# this rate limiter does not "catch up" after a blocking period
15# Limitations:
16# - only accepts limit speed in MB/s
17
18import sys
19import time
20
21MB = 1024 * 1024
22rate = float(sys.argv[1]) * MB
23start = time.time()
24total_read = 0
25
26# sys.stderr.close()  # remove error message, for Ctrl+C
27
28try:
29  buf = " "
30  while len(buf):
31    now = time.time()
32    to_read = max(int(rate * (now - start)), 1)
33    max_buf_size = 1 * MB
34    to_read = min(to_read, max_buf_size)
35    start = now
36
37    buf = sys.stdin.buffer.read(to_read)
38    sys.stdout.buffer.write(buf)
39
40except (KeyboardInterrupt, BrokenPipeError) as e:
41    pass
42