grimoire/bash/b64
2024-04-23 12:42:18 -05:00

31 lines
817 B
Bash
Executable file

#!/usr/bin/env bash
b64_encode() {
local idx=0 numerics table_idxs table_idx encoded
local table=( {A..Z} {a..z} {0..9} + / )
for (( ; idx < ${#1}; idx+=3 )); do
read -ra numerics < <(
printf '%d %d %d\n' "'${1:idx:1}" "'${1:idx+1:1}" "'${1:idx+2:1}"
)
(( table_idxs[0] = numerics[0] >> 2 ))
(( table_idxs[1] = (( (numerics[0] & 0x03) << 6) | (numerics[1] & 0xF0) >> 2) >> 2 ))
(( table_idxs[2] = (( (numerics[1] & 0x0F) << 4) | (numerics[2] & 0xC0) >> 4) >> 2 ))
(( table_idxs[3] = numerics[2] & 0x3F ))
for table_idx in "${table_idxs[@]}"; do
encoded+=${table[$table_idx]}
done
done
if (( ${#1} % 3 == 1 )); then
encoded=${encoded::-2}==
elif (( ${#1} % 3 == 2 )); then
encoded=${encoded::-1}=
fi
printf '%s\n' "$encoded"
}
b64_encode "$1"