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@cloudwu
cloudwu / ffr.c
Last active January 30, 2023 04:29
fast IEEE 754 float random
#include <stdint.h>
#include <stdlib.h>
// assert(RAND_MAX >= 0x7fff)
float
random_0_to_1() {
union {
uint32_t d;
float f;
} u;
--[[ config
root = "./"
listen = "127.0.0.1:8786"
redisaddr = "127.0.0.1:6379[1]"
dbfile = root .. "backup.db"
thread = 4
logger = nil
harbor = 1
@gunderson
gunderson / FlyCamera.cs
Last active June 27, 2024 15:18
Unity Script to give camera WASD + mouse control
using UnityEngine;
using System.Collections;
public class FlyCamera : MonoBehaviour {
/*
Writen by Windexglow 11-13-10. Use it, edit it, steal it I don't care.
Converted to C# 27-02-13 - no credit wanted.
Simple flycam I made, since I couldn't find any others made public.
Made simple to use (drag and drop, done) for regular keyboard layout
@antirez
antirez / lmdb.tcl
Created April 28, 2017 15:40
LMDB -- First version of Redis written in Tcl
# LVDB - LLOOGG Memory DB
# Copyriht (C) 2009 Salvatore Sanfilippo <antirez@gmail.com>
# All Rights Reserved
# TODO
# - cron with cleanup of timedout clients, automatic dump
# - the dump should use array startsearch to write it line by line
# and may just use gets to read element by element and load the whole state.
# - 'help','stopserver','saveandstopserver','save','load','reset','keys' commands.
# - ttl with milliseconds resolution 'ttl a 1000'. Check ttl in dump!
@shafik
shafik / WhatIsStrictAliasingAndWhyDoWeCare.md
Last active July 17, 2024 07:40
What is Strict Aliasing and Why do we Care?

What is the Strict Aliasing Rule and Why do we care?

(OR Type Punning, Undefined Behavior and Alignment, Oh My!)

What is strict aliasing? First we will describe what is aliasing and then we can learn what being strict about it means.

In C and C++ aliasing has to do with what expression types we are allowed to access stored values through. In both C and C++ the standard specifies which expression types are allowed to alias which types. The compiler and optimizer are allowed to assume we follow the aliasing rules strictly, hence the term strict aliasing rule. If we attempt to access a value using a type not allowed it is classified as undefined behavior(UB). Once we have undefined behavior all bets are off, the results of our program are no longer reliable.

Unfortunately with strict aliasing violations, we will often obtain the results we expect, leaving the possibility the a future version of a compiler with a new optimization will break code we th