https://github.com/tbielawa/bitmath
Python module for representing file sizes with different prefix notations
https://github.com/tbielawa/bitmath
files filesystem math-library python python2 python3 size-calculation sizes
Last synced: 12 months ago
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Python module for representing file sizes with different prefix notations
- Host: GitHub
- URL: https://github.com/tbielawa/bitmath
- Owner: tbielawa
- License: mit
- Created: 2014-03-08T16:19:05.000Z (about 12 years ago)
- Default Branch: master
- Last Pushed: 2024-04-17T08:22:42.000Z (almost 2 years ago)
- Last Synced: 2025-03-29T06:03:48.179Z (12 months ago)
- Topics: files, filesystem, math-library, python, python2, python3, size-calculation, sizes
- Language: Python
- Homepage: http://bitmath.readthedocs.org/en/latest/
- Size: 714 KB
- Stars: 93
- Watchers: 6
- Forks: 25
- Open Issues: 20
-
Metadata Files:
- Readme: README.rst
- Contributing: .github/CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
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bitmath
=======
`bitmath `_ simplifies many
facets of interacting with file sizes in various units. Originally
focusing on file size unit conversion, functionality now includes:
* Converting between **SI** and **NIST** prefix units (``kB`` to ``GiB``)
* Converting between units of the same type (SI to SI, or NIST to NIST)
* Automatic human-readable prefix selection (like in `hurry.filesize `_)
* Basic arithmetic operations (subtracting 42KiB from 50GiB)
* Rich comparison operations (``1024 Bytes == 1KiB``)
* bitwise operations (``<<``, ``>>``, ``&``, ``|``, ``^``)
* Reading a device's storage capacity (Linux/OS X support only)
* `argparse `_
integration as a custom type
* `click `_
integration as a custom parameter type
* `progressbar `_
integration as a better file transfer speed widget
* String parsing
* Sorting
In addition to the conversion and math operations, `bitmath` provides
human readable representations of values which are suitable for use in
interactive shells as well as larger scripts and applications. The
format produced for these representations is customizable via the
functionality included in stdlibs `string.format
`_.
In discussion we will refer to the NIST units primarily. I.e., instead
of "megabyte" we will refer to "mebibyte". The former is ``10^3 =
1,000,000`` bytes, whereas the second is ``2^20 = 1,048,576``
bytes. When you see file sizes or transfer rates in your web browser,
most of the time what you're really seeing are the base-2 sizes/rates.
**Don't Forget!** The source for bitmath `is available on GitHub
`_.
And did we mention there's almost 200 unittests? `Check them out for
yourself `_.
Running the tests should be as simple as calling the ``ci-all`` target
in the Makefile: ``make ci-all``. Please file a bug report if you run
into issues.
Installation
============
The easiest way to install bitmath is via ``dnf`` (or ``yum``) if
you're on a Fedora/RHEL based distribution. bitmath is available in
the main Fedora repositories, as well as the `EPEL6
`_
and `EPEL7
`_
repositories. There are now dual python2.x and python3.x releases
available.
**Python 2.x**:
.. code-block:: bash
$ sudo dnf install python2-bitmath
**Python 3.x**:
.. code-block:: bash
$ sudo dnf install python3-bitmath
.. note::
**Upgrading**: If you have the old *python-bitmath* package
installed presently, you could also run ``sudo dnf update
python-bitmath`` instead
**PyPi**:
You could also install bitmath from `PyPi
`_ if you like:
.. code-block:: bash
$ sudo pip install bitmath
.. note::
**pip** installs need pip >= 1.1. To workaround this, `download
bitmath `_, from
PyPi and then ``pip install bitmath-x.y.z.tar.gz``. See `issue #57
`_
for more information.
**PPA**:
Ubuntu Xenial, Wily, Vivid, Trusty, and Precise users can install
bitmath from the `launchpad PPA
`_:
.. code-block:: bash
$ sudo add-apt-repository ppa:tbielawa/bitmath
$ sudo apt-get update
$ sudo apt-get install python-bitmath
**Source**:
Or, if you want to install from source:
.. code-block:: bash
$ sudo python ./setup.py install
If you want the bitmath manpage installed as well:
.. code-block:: bash
$ sudo make install
Documentation
=============
The main documentation lives at
`http://bitmath.readthedocs.org/en/latest/
`_.
Topics include:
* The ``bitmath`` Module
* Utility Functions
* Context Managers
* Module Variables
* ``argparse`` integration
* ``click`` integration
* ``progressbar`` integration
* The ``bitmath`` command-line Tool
* Classes
* Initializing
* Available Classes
* Class Methods
* Instances
* Instance Attributes
* Instance Methods
* Instance Properties
* The Formatting Mini-Language
* Getting Started
* Tables of Supported Operations
* Basic Math
* Unit Conversion
* Rich Comparison
* Sorting
* Real Life Examples
* Download Speeds
* Calculating how many files fit on a device
* Printing Human-Readable File Sizes in Python
* Calculating Linux BDP and TCP Window Scaling
* Contributing to bitmath
* Appendices
* Rules for Math
* On Units
* Who uses Bitmath
* Related Projects
* NEWS
* Copyright
Examples
========
Arithmetic
----------
.. code-block:: python
>>> import bitmath
>>> log_size = bitmath.kB(137.4)
>>> log_zipped_size = bitmath.Byte(987)
>>> print "Compression saved %s space" % (log_size - log_zipped_size)
Compression saved 136.413kB space
>>> thumb_drive = bitmath.GiB(12)
>>> song_size = bitmath.MiB(5)
>>> songs_per_drive = thumb_drive / song_size
>>> print songs_per_drive
2457.6
Convert Units
-------------
File size unit conversion:
.. code-block:: python
>>> from bitmath import *
>>> dvd_size = GiB(4.7)
>>> print "DVD Size in MiB: %s" % dvd_size.to_MiB()
DVD Size in MiB: 4812.8 MiB
Select a human-readable unit
----------------------------
.. code-block:: python
>>> small_number = kB(100)
>>> ugly_number = small_number.to_TiB()
>>> print ugly_number
9.09494701773e-08 TiB
>>> print ugly_number.best_prefix()
97.65625 KiB
Rich Comparison
---------------
.. code-block:: python
>>> cd_size = MiB(700)
>>> cd_size > dvd_size
False
>>> cd_size < dvd_size
True
>>> MiB(1) == KiB(1024)
True
>>> MiB(1) <= KiB(1024)
True
Sorting
-------
.. code-block:: python
>>> sizes = [KiB(7337.0), KiB(1441.0), KiB(2126.0), KiB(2178.0),
KiB(2326.0), KiB(4003.0), KiB(48.0), KiB(1770.0),
KiB(7892.0), KiB(4190.0)]
>>> print sorted(sizes)
[KiB(48.0), KiB(1441.0), KiB(1770.0), KiB(2126.0), KiB(2178.0),
KiB(2326.0), KiB(4003.0), KiB(4190.0), KiB(7337.0), KiB(7892.0)]
Custom Formatting
-----------------
* Use of the custom formatting system
* All of the available instance properties
Example:
.. code-block:: python
>>> longer_format = """Formatting attributes for %s
...: This instances prefix unit is {unit}, which is a {system} type unit
...: The unit value is {value}
...: This value can be truncated to just 1 digit of precision: {value:.1f}
...: In binary this looks like: {binary}
...: The prefix unit is derived from a base of {base}
...: Which is raised to the power {power}
...: There are {bytes} bytes in this instance
...: The instance is {bits} bits large
...: bytes/bits without trailing decimals: {bytes:.0f}/{bits:.0f}""" % str(ugly_number)
>>> print ugly_number.format(longer_format)
Formatting attributes for 5.96046447754 MiB
This instances prefix unit is MiB, which is a NIST type unit
The unit value is 5.96046447754
This value can be truncated to just 1 digit of precision: 6.0
In binary this looks like: 0b10111110101111000010000000
The prefix unit is derived from a base of 2
Which is raised to the power 20
There are 6250000.0 bytes in this instance
The instance is 50000000.0 bits large
bytes/bits without trailing decimals: 6250000/50000000
Utility Functions
-----------------
**bitmath.getsize()**
.. code-block:: python
>>> print bitmath.getsize('python-bitmath.spec')
3.7060546875 KiB
**bitmath.parse_string()**
Parse a string with standard units:
.. code-block:: python
>>> import bitmath
>>> a_dvd = bitmath.parse_string("4.7 GiB")
>>> print type(a_dvd)
>>> print a_dvd
4.7 GiB
**bitmath.parse_string_unsafe()**
Parse a string with ambiguous units:
.. code-block:: python
>>> import bitmath
>>> a_gig = bitmath.parse_string_unsafe("1gb")
>>> print type(a_gig)
>>> a_gig == bitmath.GB(1)
True
>>> bitmath.parse_string_unsafe('1gb') == bitmath.parse_string_unsafe('1g')
True
**bitmath.query_device_capacity()**
.. code-block:: python
>>> import bitmath
>>> with open('/dev/sda') as fp:
... root_disk = bitmath.query_device_capacity(fp)
... print root_disk.best_prefix()
...
238.474937439 GiB
**bitmath.listdir()**
.. code-block:: python
>>> for i in bitmath.listdir('./tests/', followlinks=True, relpath=True, bestprefix=True):
... print i
...
('tests/test_file_size.py', KiB(9.2900390625))
('tests/test_basic_math.py', KiB(7.1767578125))
('tests/__init__.py', KiB(1.974609375))
('tests/test_bitwise_operations.py', KiB(2.6376953125))
('tests/test_context_manager.py', KiB(3.7744140625))
('tests/test_representation.py', KiB(5.2568359375))
('tests/test_properties.py', KiB(2.03125))
('tests/test_instantiating.py', KiB(3.4580078125))
('tests/test_future_math.py', KiB(2.2001953125))
('tests/test_best_prefix_BASE.py', KiB(2.1044921875))
('tests/test_rich_comparison.py', KiB(3.9423828125))
('tests/test_best_prefix_NIST.py', KiB(5.431640625))
('tests/test_unique_testcase_names.sh', Byte(311.0))
('tests/.coverage', KiB(3.1708984375))
('tests/test_best_prefix_SI.py', KiB(5.34375))
('tests/test_to_built_in_conversion.py', KiB(1.798828125))
('tests/test_to_Type_conversion.py', KiB(8.0185546875))
('tests/test_sorting.py', KiB(4.2197265625))
('tests/listdir_symlinks/10_byte_file_link', Byte(10.0))
('tests/listdir_symlinks/depth1/depth2/10_byte_file', Byte(10.0))
('tests/listdir_nosymlinks/depth1/depth2/10_byte_file', Byte(10.0))
('tests/listdir_nosymlinks/depth1/depth2/1024_byte_file', KiB(1.0))
('tests/file_sizes/kbytes.test', KiB(1.0))
('tests/file_sizes/bytes.test', Byte(38.0))
('tests/listdir/10_byte_file', Byte(10.0))
Formatting
----------
.. code-block:: python
>>> with bitmath.format(fmt_str="[{value:.3f}@{unit}]"):
... for i in bitmath.listdir('./tests/', followlinks=True, relpath=True, bestprefix=True):
... print i[1]
...
[9.290@KiB]
[7.177@KiB]
[1.975@KiB]
[2.638@KiB]
[3.774@KiB]
[5.257@KiB]
[2.031@KiB]
[3.458@KiB]
[2.200@KiB]
[2.104@KiB]
[3.942@KiB]
[5.432@KiB]
[311.000@Byte]
[3.171@KiB]
[5.344@KiB]
[1.799@KiB]
[8.019@KiB]
[4.220@KiB]
[10.000@Byte]
[10.000@Byte]
[10.000@Byte]
[1.000@KiB]
[1.000@KiB]
[38.000@Byte]
[10.000@Byte]
``argparse`` Integration
------------------------
Example script using ``bitmath.integrations.bmargparse.BitmathType`` as an
argparser argument type:
.. code-block:: python
import argparse
from bitmath.integrations.bmargparse import BitmathType
parser = argparse.ArgumentParser(
description="Arg parser with a bitmath type argument")
parser.add_argument('--block-size',
type=BitmathType,
required=True)
results = parser.parse_args()
print "Parsed in: {PARSED}; Which looks like {TOKIB} as a Kibibit".format(
PARSED=results.block_size,
TOKIB=results.block_size.Kib)
If ran as a script the results would be similar to this:
.. code-block:: bash
$ python ./bmargparse.py --block-size 100MiB
Parsed in: 100.0 MiB; Which looks like 819200.0 Kib as a Kibibit
``click`` Integration
---------------------
Example script using ``bitmath.integrations.bmclick.BitmathType`` as an
click parameter type:
.. code-block:: python
import click
from bitmath.integrations.bmclick import BitmathType
@click.command()
@click.argument('size', type=BitmathType())
def best_prefix(size):
click.echo(size.best_prefix())
If ran as a script the results should be similar to this:
.. code-block:: bash
$ python ./bestprefix.py "1024 KiB"
1.0 MiB
``progressbar`` Integration
---------------------------
Use ``bitmath.integrations.bmprogressbar.BitmathFileTransferSpeed`` as a
``progressbar`` file transfer speed widget to monitor download speeds:
.. code-block:: python
import requests
import progressbar
import bitmath
from bitmath.integrations.bmprogressbar import BitmathFileTransferSpeed
FETCH = 'https://www.kernel.org/pub/linux/kernel/v3.0/patch-3.16.gz'
widgets = ['Bitmath Progress Bar Demo: ', ' ',
progressbar.Bar(marker=progressbar.RotatingMarker()), ' ',
BitmathFileTransferSpeed()]
r = requests.get(FETCH, stream=True)
size = bitmath.Byte(int(r.headers['Content-Length']))
pbar = progressbar.ProgressBar(widgets=widgets, maxval=int(size),
term_width=80).start()
chunk_size = 2048
with open('/dev/null', 'wb') as fd:
for chunk in r.iter_content(chunk_size):
fd.write(chunk)
if (pbar.currval + chunk_size) < pbar.maxval:
pbar.update(pbar.currval + chunk_size)
pbar.finish()
If ran as a script the results would be similar to this:
.. code-block:: bash
$ python ./smalldl.py
Bitmath Progress Bar Demo: ||||||||||||||||||||||||||||||||||||||||| 1.58 MiB/s