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roblogic/btoz85

Last active May 28, 2020 03:23
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Z85 encoding implemented in Zsh.. Input: binary string (length 32). Output: Z85 ascii-encoded string (length 5). Spec: https://rfc.zeromq.org/spec:32/Z85/
Raw
btoz85
#!/bin/zsh
# Version 0.00.01 - bare bones only
# Binary to Ascii conversion, using Z85 encoding algorithm
# Similar to Ascii85, few different characters, doesn't use ascii code table
# https://www.johndcook.com/blog/2019/03/05/base85-encoding/
# https://rfc.zeromq.org/spec:32/Z85/
# Example: (input must be 32 characters)
# input 01001101011000010110111000100000
# base85 24 73 80 78 61
# Z85 o&{[Z
#set -x
#Translation table
Z=({0..9} {a..z} {A..Z} \" . - : + = ^ ! / \* \? \& \< \> \( \) [ ] { \} @ % \$ \# )
#Conversion to Z85
#binary ==> radix 85 ==> Z85 ascii
X=$(for n (`bc<<<"obase=85;ibase=2;$1"`)printf %s $Z[$n+1])
#left pad with 0 if there are fewer than 5 digits
p=$[5-${#X}]
printf %s ${(l:$p::0:)}$X
Raw
original-arecibo-message.txt
0000001010101000000000000101000001010000000100100010001000100101100101010101010101010010010000000000000000000000000000000000000110000000000000000000110100000000000000000001101000000000000000000101010000000000000000001111100000000000000000000000000000000110000111000110000110001000000000000011001000011010001100011000011010111110111110111110111110000000000000000000000000010000000000000000010000000000000000000000000000100000000000000000111111000000000000011111000000000000000000000001100001100001110001100010000000100000000010000110100001100011100110101111101111101111101111100000000000000000000000000100000011000000000100000000000110000000000000001000001100000000001111110000011000000111110000000000110000000000000100000000100000000100000100000011000000010000000110000110000001000000000011000100001100000000000000011001100000000000001100010000110000000001100001100000010000000100000010000000010000010000000110000000010001000000001100000000100010000000001000000010000010000000100000001000000010000000000001100000000011000000001100000000010001110101100000000000100000001000000000000001000001111100000000000010000101110100101101100000010011100100111111101110000111000001101110000000001010000011101100100000010100000111111001000000101000001100000010000011011000000000000000000000000000000000001110000010000000000000011101010001010101010100111000000000101010100000000000000001010000000000000011111000000000000000011111111100000000000011100000001110000000001100000000000110000000110100000000010110000011001100000001100110000100010100000101000100001000100100010010001000000001000101000100000000000010000100001000000000000100000000010000000000000010010100000000000111100111110100111100000000000000000000
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roblogic commented May 28, 2020

BUG: The double quote character (") is not valid Z85 and should not be in the translation table!

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