iomonad

(ns cljsandbox.lattices)

;; euler 15

(defn ! [x]
  (reduce *' (range 1 (inc x))))

(defn lattices-paths [x]
  (/ (! (* 2 x)) (* (! x)) (! x)))

iomonad

(ns cljsandbox.collatz)

(defn next-collatz [n]
  "Return the next step"
  {:pre [(> n 0)]}
  (cond
    (even? n) (-> n (/ 2))
    (odd? n) (-> n (* 3) (inc))))

(defn collatz [n]

iomonad

defmodule Expng do

  defstruct [:width, :height, :bit_depth, :color_type, :compression, :filter, :interlace, :chunks]

  def png_parse(<<
  0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A,
                 _length :: size(32),
                 "IHDR",
                 width :: size(32),
                 height :: size(32),

iomonad

File.stream!("/etc/passwd") 
  |> Enum.chunk_every(4) 
  |> Enum.flat_map(&(Enum.map(&1, fn x -> String.length(x) end)))

iomonad

iomonad

Moved to git repository: https://github.com/denji/nginx-tuning

NGINX Tuning For Best Performance

For this configuration you can use web server you like, i decided, because i work mostly with it to use nginx.

Generally, properly configured nginx can handle up to 400K to 500K requests per second (clustered), most what i saw is 50K to 80K (non-clustered) requests per second and 30% CPU load, course, this was 2 x Intel Xeon with HyperThreading enabled, but it can work without problem on slower machines.

You must understand that this config is used in testing environment and not in production so you will need to find a way to implement most of those features best possible for your servers.

iomonad

A primer on some C obfuscation tricks.

Typedef abuse:

1) normal expected form:
	typedef signed int my_int;

2) abuse it by:
	signed int typedef my_int;
	int typedef signed my_int;

iomonad

class Notify:
    def __init__(self, name):
        self._name = name    def __set__(self, instance, value):
        instance.__dict__[self._name] = value
        for callback in instance.__dict__[f"__notify_{self._name}"]:
            callback(value)

def watch(instance, field, callback):
    setattr(instance.__class__, field, Notify(field))
    instance.__dict__.setdefault(f"__notify_{field}", []).append(callback)

iomonad

Common

export OPT=/opt
export BUILDS=/some/where/mini_linux
mkdir -p $BUILDS

Linux kernel

iomonad

//
// file: paginate.js
//

function pagination(c, max, count) {
    var current = c,
	last = max,
	left = current - count,
	right = current + count + 1,
	range = [],