#!/bin/bash
# Playing with Ascii85:     https://en.wikipedia.org/wiki/Ascii85
# (C) 2016-2023 Felix Hauri - felix@f-hauri.ch
# Licensed under terms of GPL v3. www.gnu.org

a85e() { local LANG=C {f..r}     # Ascii 85 encoder bash script
printf -v n \\%o {32..126};printf -v n "$n";printf -v m %-20sE abtnvfr;p=\<~;l()
{ q=$(($1<<24|$2<<16|$3<<8|$4));q="${n:1+(q/64#378iN)%85:1}${n:1+(q/614125)%85:1
}${n:1+(q/7225)%85:1}${n:1+(q/85)%85:1}${n:1+q%85:1}";};k() { ((${#p}>74))&&ech\
o "${p:0:75}" && p=${p:75};};while IFS= read -rd '' -n 1 q;do [ "$q" ]&&{ print\
f -v q "%q" "$q";case ${#q} in 1|2)q=${n%$q*};o+=($((${#q}+32)));;7)q=${q#*\'\\}
o+=($((8#${q%\'})));;5)q=${q#*\'\\};q=${m%${q%\'}*};o+=($((${#q}+07)));;esac;}||
o+=(0);((${#o[@]}>3))&&{ [ "${o[*]}" = "0 0 0 0" ]&& q=z|| l ${o[@]};p+="${q}";k
o=(); };done;[ "$o" ]&&{ f=0;for((;${#o[@]}<4;)){ o+=(0);((f++));};((f==0))&&[ \
"${o[*]}" = "0 0 0 0" ]&&q=z||l ${o[@]};p+="${q:0:5-f}";};p+="~>";k;[ "$p" ]&&e\
cho "$p";}
a85d() { local LANG=C {f..r}     # Ascii 85 decoder bash script
printf -v n "\%o" {33..117};printf -v n "$n";o=1 k=1;j(){ read -r q||o=;[ "$q" \
]&&[ -z "${q//*<~*}" ]&&((k))&&k= q="${q#*<~}";m+="${q// }";m="${m%~>*}";};l() {
r=;for((i=0;i<${#1};i++)){ s="${1:i:1}";case "$s" in "*"|\\|\?)s=\\${s};;esac;s\
="${n%${s}*}";((r+=${#s}*(85**(4-i))));};printf -v p "\%03o" $((r>>24)) $((r>>16
&255)) $((r>>8&255)) $((r&255));};for((;o+${#m}>0;)) { [ "$m" ]||j;while [ "${m:
0:1}" = "z" ];do m=${m:1};printf "\0\0\0\0";done;if [ ${#m} -ge 5 ];then q="${m:
0:5}";m=${m:5};l "${q}";printf "$p";elif ((o)); then j;elif [ "${m##z*}" ]; then
printf -v t %$((5-${#m}))s;l "$m${t// /u}"; printf "${p:0:16-4*${#t}}";m=;fi;};}

## Quick demonstration (exit here if sourced.)
[[ $0 = "${BASH_SOURCE[0]}" ]] || { true; return 0;}
set -v
## Quick demonstration (exit here if sourced.)

### String 'Hello world!!':
read line < <(a85e <<<'Hello world!!')
echo "$line"

a85d <<<"$line"

### Same but in two pass, using zstd in between:
read line < <(a85e < <(zstd < <(a85e <<<'Hello world!!')))
echo "$line"

a85d < <(zstdcat <(a85d <<<"$line"))

### A quote from Thomas Hobbes's Leviathan:
mapfile -t hobbesCit < <(a85e <<-EOF
Man is distinguished, not only by his reason,  but by this singular passion
from other animals,  which is a lust of the mind, that by a perseverance of
delight in the continued and indefatigable generation of knowledge, exceeds
the short vehemence of any carnal pleasure.
	EOF

)

printf '%s\n' "${hobbesCit[@]}"

a85d <<<"${hobbesCit[*]}"