unix1’s gists

unix1 / cloudformation-fastmail-mx-spf-dkim.yml

Created June 14, 2021 14:09

Cloudformation template for fastmail MX/SPF/DKIM records described on https://www.fastmail.com/help/receive/domains-setup-mxonly.html

	Parameters:

	Domain:
	Description: Domain for hosted zone, e.g. example.com
	Type: String

	Resources:

	WebHostedZone:
	Type: AWS::Route53::HostedZone

unix1 / rle.lisp

Last active February 26, 2016 14:57

Implementation of Run-length encoding algorithm in LISP. Both encode and decode functions are provided. For more info see https://en.wikipedia.org/wiki/Run-length_encoding and http://rosettacode.org/wiki/Run-length_encoding - the latter has the loop implementation, but I like the tail call optimized recursive implementation better (but I'm still…

	(defun rle-encode (lst)
	(reverse (rle-lib-encode lst nil)))

	(defun rle-lib-encode (lst acc)
	(if (null lst)
	acc
	(let ((curr (car lst))
	(prev (car acc))
	(cnt (car (cdr acc))))
	(if (equal curr prev)

unix1 / rle.erl

Created February 25, 2016 06:23

Implementation of Run-length encoding algorithm in Erlang. Both encode and decode functions are provided. For more info see https://en.wikipedia.org/wiki/Run-length_encoding and http://rosettacode.org/wiki/Run-length_encoding - the latter has a couple of implementations in Erlang, but I like using lists:foldr/3 this way.

	-module(rle).

	-export([encode/1]).
	-export([decode/1]).

	encode(List) ->
	lists:flatten(lists:foldr(
	fun (Prev, [[Count, Prev]\|Rest]) ->
	[[Count + 1, Prev]\|Rest];
	(Current, Acc) ->

unix1 / perftest.erl

Created August 10, 2014 16:44

Measure average execution time of a function. I don't claim any credit, I took http://erlangcentral.org/wiki/index.php/Measuring_Function_Execution_Time and put it in a module for convenience.

	-module(perftest).

	-export([test_avg/4]).

	test_avg(M, F, A, N) when N > 0 ->
	L = test_loop(M, F, A, N, []),
	Length = length(L),
	Min = lists:min(L),
	Max = lists:max(L),
	Med = lists:nth(round((Length / 2)), lists:sort(L)),

unix1 / binary2.erl

Last active August 29, 2015 14:04

Erlang stdlib provides string:join/2 function but not binary:join/2. Below are few options how to do binary:join/2. Guess which one is the fastest.

	-module(binary2).

	-export([joinl/2]).
	-export([joinfl/2]).
	-export([joinfr/2]).

	% use list comprehension
	joinl([], Sep) when is_binary(Sep) ->
	<<>>;
	joinl([H\|T], Sep) ->

unix1 / test-matrix-invert.php

Last active September 18, 2022 13:09

A sample matrix inversion in PHP using Gauss-Jordan elimination. This is implementation is meant for clarity, not for performance, memory usage, or numerical stability. You can optionally turn on the debug flag to output matrix state after every iteration. See https://en.wikipedia.org/wiki/Gauss-Jordan_elimination for more info. Enjoy!

	<?php

	/**
	* Inverts a given matrix
	*
	* @param array $A matrix to invert
	* @param boolean $debug whether to print out debug info
	*
	* @return array inverted matrix
	*/

unix1 / test-peb-session.php

Last active December 18, 2015 18:59

Sample page to illustrate and test PHP session storage in Erlang Mnesia via mypeb PHP extension and kvstore application. Full instructions are here: https://unix0.wordpress.com/2013/06/22/php-sessions-in-erlang-mnesia/

	<html>

	<body>

	<h1>Test Peb Page</h1>
	<p>This page starts a session and keeps a counter in a session variable.</p>
	<p>It uses kvstore application to store PHP sessions in Erlang Mnesia.</p>
	<div><a href="test-peb-session.php">Reload this page</a> to increment the counter.</div>
	<?php
	interface SessionHandlerInterface {}