function password(n){
if (n < 3) n = 3;
let randomIndex=0;
const randomArray = new Uint32Array((n << 1) - 1);
window.crypto.getRandomValues(randomArray);
const random = n => randomArray[randomIndex++] % n;
const randOf = s => s.charAt(random(s.length));
const shuffle = (s) => {
let c = [...s];
let n = c.length;
for(let i = n - 1; i > 0; i--){
let j = random(i + 1);
let tmp = c[i];
c[i] = c[j];
c[j] = tmp;
}
return c;
};
let a=[];
for(let i=0;i<n-3;i++){
a.push(randOf("abcdefghijklmnopqrstuvwxyz"));
}
a.push(randOf("ABCDEFGHIJKLMNOPQRSTUVWXYZ"));
a.push(randOf("01234567890"));
a.push(randOf("!\"£$%^&*()-_+=[]{}:;@'~#<>,./?"));
return shuffle(a).join("");
}
Friday 3 November 2017
How to generate a not totally crap password in Javascript
I keep writing versions of this in various languages and then losing them. I'm posting it here so I'll have a version I can run in my browser whenever I need a new password for something. The password generated will often be harder to guess than one I would just make up, but that's the only guarantee I'm giving.
Thursday 24 November 2016
How to convert from kebab-case to camelCase in Clojure
Here are six functions that do that. Pick your favourite. It won't be the best performing one. Can you guess which that is? Scroll down for answer.
(defn kebab->camel1 [^String kebab]
(->> kebab
(reduce
(fn [[buf ucase] c]
(let [dash (= \- c)]
[(if dash
buf
(conj buf (if ucase
(Character/toUpperCase c)
c)))
dash]))
[[] false])
first
(apply str)))
(defn kebab->camel2 [^String kebab]
(->> (map
(fn [cur prev] (if (= \- prev)
(Character/toUpperCase cur)
cur)) kebab (cons nil kebab))
(filter #(not= \- %))
(apply str)))
(defn kebab->camel3 [^String kebab]
(loop [buf []
ucase false
rst kebab]
(if (seq rst)
(let [c (first rst)
dash (= \- c)]
(recur (if dash
buf
(conj buf (if ucase
(Character/toUpperCase c)
c)))
dash
(rest rst)))
(apply str buf))))
(defn kebab->camel4 [^String kebab]
(->> (map
(fn [[prev cur]] (if (= \- prev)
(Character/toUpperCase cur)
cur)) (partition 2 1 (cons nil kebab)))
(filter #(not= \- %))
(apply str)))
(defn kebab->camel5 [^String kebab]
(let [pv (volatile! nil)
sb (StringBuilder. (count kebab))]
(doseq [c kebab]
(let [prior @pv
dash (= \- c)]
(vreset! pv dash)
(when-not dash (.append
sb
(if prior
(Character/toUpperCase c) c)))))
(.toString sb)))
(defn kebab->camel6 [^String kebab]
(let [buf (.toCharArray kebab)
len (count buf)]
(loop [src 0 dst 0 ucase nil]
(if (< src len)
(let [c (aget buf src)
dash (= \- c)]
(when-not dash (aset buf dst (if ucase (Character/toUpperCase c) c)))
(recur (inc src) (if dash dst (inc dst)) dash))
(String. buf 0 dst)))))
To see which is best we do this
(let [kebab (->> (.ints (java.util.Random. 17) 0 31)
.iterator
iterator-seq
dedupe
(map #(nth "abcdefghijklmnopqrstuvwxyz-----" %))
(take 10000)
(apply str))
time-fn (fn [f]
(let [start (System/nanoTime)]
(f)
(/ (double (- (System/nanoTime) start)) 1000000.0)))]
(for [f [kebab->camel1
kebab->camel2
kebab->camel3
kebab->camel4
kebab->camel5
kebab->camel6]]
[f (time-fn #(dotimes [_ 1000] (f kebab)))]))
and get results like these
([#function[user/kebab->camel1] 9064.630932] [#function[user/kebab->camel2] 11520.793361] [#function[user/kebab->camel3] 8440.000948] [#function[user/kebab->camel4] 20740.882337] [#function[user/kebab->camel5] 8455.671506] [#function[user/kebab->camel6] 99.724767])
Wednesday 23 November 2016
How to get Structure and Interpretation of Computer Programs as an Info file on your system
sudo dnf install texi2html texinfo git clone https://github.com/webframp/sicp-info.git cd sicp-info/ makeinfo --no-split sicp.texi -o sicp.info gzip sicp.info sudo install-info sicp.info.gz /usr/share/info/dir sudo mv sicp.info.gz /usr/share/info
Monday 14 November 2016
My crazy keyboard configuration
I have this in my .Xmodmap file.clear mod5 clear mod4 clear lock clear control keycode 49 = ISO_Level3_Shift keycode 66 = Menu NoSymbol Menu keycode 37 = Super_L NoSymbol Super_L keycode 133 = Control_L NoSymbol Control_L keycode 108 = Alt_L keycode 134 = Control_R NoSymbol Control_R add mod5 = ISO_Level3_Shift add mod4 = Super_L Hyper_R add control = Control_L Control_R keycode 10 = 1 exclam 1 exclam grave onesuperior exclamdown keycode 11 = 2 quotedbl 2 quotedbl notsign twosuperior trademark keycode 12 = 3 sterling 3 sterling brokenbar threesuperior copyright
It turns my Windows keys into Ctrl keys, my left Ctrl key into a Windows key, my Caps Lock key into a menu (▤) key, my AltGr key into a regular Alt key and it turns the key directly below Esc (I call it backtick) into an AltGr. To access the characters that were on that key I type my new AltGr + 1 or 2 or 3.
Why these changes?
- I need a symmetrical ctrl key arrangement (on both my desktop and laptop).
- I need a symmetrical alt key arrangement. (I'm an Emacs user.)
- But I still need an AltGr key
- I have customized Emacs to make the menu key very useful (following Xah Lee's advice), that's why I've moved it to the easy-to-reach Caps Lock position.
Thursday 3 November 2016
How to create a Java (/Clojure/Scala) service on Linux
This is a sort of a continuation of an earlier post. In that post I said that you have to create a shell file called test-service or whatever in /etc/init.d/.
You will need Apache Jsvc. Your Java (or whatever JVM language) code will include a class that implements org.apache.commons.daemon.Daemon.
Here is what you should put in that shell file to make you JVM thing into a Linux service called test-service (test.daemon.Daemon is the class you wrote which implements org.apache.commons.daemon.Daemon).
#! /bin/sh
### BEGIN INIT INFO
# Provides: test-service
# Required-Start:
# Required-Stop:
# Default-Start: S
# Default-Stop:
# X-Start-Before:
# Short-Description:
# Description: test-service
### END INIT INFO
export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
SVC_DIR=/home/mikey/test-service
case "$1" in
start|"")
/usr/bin/jsvc -wait 20 -cwd $SVC_DIR -pidfile $SVC_DIR/test-service.pid -outfile $SVC_DIR/out.log -errfile $SVC_DIR/err.log -cp $SVC_DIR/target/test-service-0.1-standalone.jar test.daemon.Daemon
exit $?
;;
restart|reload|force-reload)
echo "Error: argument '$1' not supported" >&2
exit 3
;;
stop)
/usr/bin/jsvc -wait 20 -stop -cwd $SVC_DIR -pidfile $SVC_DIR/test-service.pid -outfile $SVC_DIR/out.log -errfile $SVC_DIR/err.log -cp $SVC_DIR/target/test-service-0.1-standalone.jar test.daemon.Daemon
exit $?
;;
status)
# No-op
;;
*)
echo "Usage: test-service.sh [start|stop]" >&2
exit 3
;;
esac
:
Friday 7 October 2016
Make Caps Lock an additional Menu key
Use the localectl command.
localectl [--no-convert] set-x11-keymap layout [model [variant [options]]]
To make caps lock an additional menu key, the options parameter should be caps:menu
To figure out what the other parameters should be, enter this command:
setxkbmap -print -verbose 10
The command I ended up with was
localectl --no-convert set-x11-keymap gb pc105 mac caps:menu
See Keyboard configuration in Xorg for more details.
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