bytesfunc 2.0.0

Fast bytes and bytearray processing functions

Authors:

Michael Griffin

Version:

2.0.0 for 2020-04-03

Copyright:

2014 - 2020

License:

This document may be distributed under the Apache 2.0 License.

Language:

Python 3.5 or later

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Introduction

The BytesFunc module provides high speed array processing functions for use with Python ‘bytes’ and ‘bytearray’ objects. These functions are patterned after the functions in the standard Python “operator” module together with some additional ones from other sources.

The purpose of these functions is to perform mathematical calculations on “bytes” and “bytearray” objects significantly faster than using native Python.

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Function Summary

The compare operators used for ‘ball’, ‘bany’, and ‘findindex’ are examples only, and other compare operations are available. Many functions will accept other parameter combinations of sequences and numeric parameters. See the details for each function for what parameter combinations are valid.

Brief Description

Function	Equivalent to
and_	Perform a bitwise AND across the sequence.
ball	True if all elements of the sequence meet the match criteria.
bany	True if any elements of the sequence meet the match criteria.
bmax	Return the maximum value in the sequence.
bmin	Return the minimum value in the sequence.
bsum	Return the sum of the sequence.
eq	True if all elements of the sequence equal the compare value.
findindex	Returns the index of the first value in an array to meet the specified criteria.
ge	True if all elements of the sequence are greater than or equal to the compare value.
gt	True if all elements of the sequence are greater than the compare value.
invert	Perform a bitwise invert across the sequence.
le	True if all elements of the sequence are less than or equal to the compare value.
lshift	Perform a bitwise left shift across the sequence.
lt	True if all elements of the sequence are less than the compare value.
ne	True if all elements of the sequence are not equal the compare value.
or_	Perform a bitwise OR across the sequence.
rshift	Perform a bitwise right shift across the sequence.
xor	Perform a bitwise XOR across the sequence.

Python Equivalent

Function	Equivalent to
and_	[x & param for x in sequence1]
ball	all([(x > param) for x in array])
bany	any([(x > param) for x in array])
bmax	max(sequence)
bmin	min(sequence)
bsum	sum(sequence)
eq	all([x == param for x in sequence])
findindex	[x for x,y in enumerate(array) if y > param][0]
ge	all([x >= param for x in sequence])
gt	all([x > param for x in sequence])
invert	[~x for x in sequence1]
le	all([x <= param for x in sequence])
lshift	[x << param for x in sequence1]
lt	all([x < param for x in sequence])
ne	all([x != param for x in sequence])
or_	[x | param for x in sequence1]
rshift	[x >> param for x in sequence1]
xor	[x ^ param for x in sequence1]

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Supported Sequence Types

BytesFunc supports Python native “bytes” and “bytearray” objects.

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Performance

Average performance increase on x86_64 Ubuntu with GCC is 600 times faster than native Python. Performance will vary depending on the function, with the performance increase ranging from 7 times to 1500 times.

Other platforms show similar improvements.

Detailed performance figures are listed in the full documentation.

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Platform support

BytesFunc is written in ‘C’ and uses the standard C libraries to implement the underlying math functions. BytesFunc has been tested on the following platforms.

OS	Bits	Compiler	Python Version Tested
Ubuntu 18.04 LTS	64 bit	GCC	3.6
Ubuntu 19.10	64 bit	GCC	3.7
Ubuntu 20.04 beta	64 bit	GCC	3.8
Debian 10	32 bit	GCC	3.7
Debian 10	64 bit	GCC	3.7
OpenSuse 15	64 bit	GCC	3.6
Centos 8	64 bit	GCC	3.6
FreeBSD 12	64 bit	LLVM	3.7
OpenBSD 6.5	64 bit	LLVM	3.6
MS Windows 10	64 bit	MS Visual Studio C 2015	3.8
Raspbian (RPi 3)	32 bit	GCC	3.7
Ubuntu 19.10 ARM	64 bit	GCC	3.7

• The Raspbian (RPi 3) tests were conducted on a Raspberry Pi 3 ARM CPU running in 32 bit mode.

• The Ubuntu ARM tests were conducted on a Raspberry Pi 3 ARM CPU running in 64 bit mode.

• All others were conducted using VMs running on x86 hardware.

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Installation

Please note that this is a Python 3 package. To install using Pip, you will need (with Debian package in brackets):

• The appropriate C compiler and header files (gcc and build-essential).

• The Python3 development headers (python3-dev).

• Pip3 together with the corresponding Setuptools (python3-pip).

example:

# Install from PyPI.
pip3 install arrayfunc
# Install from a local copy of the source package (Linux).
pip3 install --no-index --find-links=. arrayfunc
# Windows seems to use "pip" instead of "pip3" for some reason.
pip install arrayfunc

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Release History

• 2.0.0 - Added SIMD support for ARMv8 AARCH64. This is 64 bit ARM on a

  Raspberry Pi3 when running 64 bit Ubuntu. Raspbian is 32 bit only and has 64 bit SIMD vectors. 64 bit ARM has 128 bit SIMD vectors and so offers improved performance.

• 1.0.0 - First release.