Benchmark for python-hyper/hpack#62.

README.md

To run this benchmark, clone this gist, cd into the directory, and then run tox. This will print a set of results.

main.py

from __future__ import print_function

import platform
import sys
import timeit

is_py2 = (sys.version_info[0] == 2)

if is_py2:
    def to_byte(char):
        return ord(char)
else:
    def to_byte(char):
        return char


def decode_integer_old(data, prefix_bits):
    max_number = (2 ** prefix_bits) - 1
    mask = 0xFF >> (8 - prefix_bits)
    index = 0

    number = to_byte(data[index]) & mask

    if number == max_number:

        while True:
            index += 1
            next_byte = to_byte(data[index])

            if next_byte >= 128:
                number += (next_byte - 128) * (128 ** (index - 1))
            else:
                number += next_byte * (128 ** (index - 1))
                break

    return number, index + 1

def decode_integer_new(data, prefix_bits):
    max_number = (2 ** prefix_bits) - 1
    mask = 0xFF >> (8 - prefix_bits)
    index = 0
    shift = 0

    number = to_byte(data[index]) & mask

    if number == max_number:

        while True:
            index += 1
            next_byte = to_byte(data[index])

            if next_byte >= 128:
                number += (next_byte - 128) << shift
            else:
                number += next_byte << shift
                break

            shift += 7

    return number, index + 1


inputs = (
    (b'\x0f\xf1\xff\x3f', 4),
    (b'\x1f\xe1\xff\x3f', 5),
    (b'\x3f\xc1\xff\x3f', 6),
    (b'\x7f\x81\xff\x3f', 7),
)


if __name__ == '__main__':
    for data, prefix_bits in inputs:
        for func in ("decode_integer_old", "decode_integer_new"):
            print("{} {} {} (prefix bits {:d})".format(
                platform.python_implementation(),
                platform.python_version(),
                func,
                prefix_bits,
            ))
            timer = timeit.Timer(
                stmt="{}({!r}, {:d})".format(func, data, prefix_bits),
                setup="from main import {}".format(func)
            )
            results = timer.repeat()
            print(results)

tox.ini

[tox]
envlist = py27, py33, py34, py35, pypy
skipsdist= True

[testenv]
commands= python main.py