Base64 decode data: Difference between revisions

</pre>

=={{header|Rust}}==

<lang rust>use std::str;

const INPUT: &str = "VG8gZXJyIGlzIGh1bWFuLCBidXQgdG8gcmVhbGx5IGZvdWwgdGhpbmdzIHVwIHlvdSBuZWVkIGEgY29tcHV0ZXIuCiAgICAtLVBhdWwgUi5FaHJsaWNo";

const UPPERCASE_OFFSET: i8 = -65;

const LOWERCASE_OFFSET: i8 = 26 - 97;

const NUM_OFFSET: i8 = 52 - 48;

fn main() {

println!("Input: {}", INPUT);

let result = INPUT.chars()

.filter(|&ch| ch != '=') //Filter '=' chars

.map(|ch| { //Map char values using Base64 Characters Table

let ascii = ch as i8;

let convert = match ch {

'0' ... '9' => ascii + NUM_OFFSET,

'a' ... 'z' => ascii + LOWERCASE_OFFSET,

'A' ... 'Z' => ascii + UPPERCASE_OFFSET,

'+' => 62,

'/' => 63,

_ => panic!("Not a valid base64 encoded string")

};

format!("{:#08b}", convert)[2..].to_string() //convert indices to binary format and remove the two first digits

})

.collect::<String>() //concatenate the resulting binary values

.chars()

.collect::<Vec<char>>()

.chunks(8) //split into 8 character chunks

.map(|chunk| {

let num_str = chunk.iter().collect::<String>();

usize::from_str_radix(&num_str, 2).unwrap() as u8 //convert the binary string into its u8 value

})

.collect::<Vec<_>>();

let result = str::from_utf8(&result).unwrap(); //convert into UTF-8 string

println!("Output: {}", result);

}</lang>

{{out}}

<pre>

Input: VG8gZXJyIGlzIGh1bWFuLCBidXQgdG8gcmVhbGx5IGZvdWwgdGhpbmdzIHVwIHlvdSBuZWVkIGEgY29tcHV0ZXIuCiAgICAtLVBhdWwgUi5FaHJsaWNo

Output: To err is human, but to really foul things up you need a computer.

--Paul R.Ehrlich