Broken b64 implementation (Ugly and no padding)
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959093c408
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f8a7c5527a
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@ -5,29 +5,88 @@
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////
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use std::env;
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use std::convert::TryInto;
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static BASE64_TABLE: &'static [char] = &['A','B','C','D','E','F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V' ,'W' ,'X' ,'Y' ,'Z',
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'a','b','c','d','e','f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v' ,'w' ,'x' ,'y' ,'z',
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'0','1','2','3','4','5', '6', '7', '8', '9', '+', '/'];
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/// Convert Hex String to char
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///
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/// # Examples
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///
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/// ~~~
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/// hex_to_char("49") => I
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/// ~~~
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/// TODO: the name is not accurate. Take a string and convert to u8
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fn hex_to_char(s: &str) -> Result<char, std::num::ParseIntError> {
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u8::from_str_radix(s, 16).map(|n| n as char)
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u8::from_str_radix(s, 16).map(|n| n as char)
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}
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fn main() {
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let args: Vec<String> = env::args().collect();
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let input = &args[1];
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let args: Vec<String> = env::args().collect();
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let input = &args[1];
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let char_vec: Vec<char> = input.chars().collect();
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let split = &char_vec.chunks(2)
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.map(|chunk| chunk.iter().collect::<String>())
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.collect::<Vec<_>>();
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let mut input_str = String::new();
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// Printing the string in Ascii format - for decoding example
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for (i, s) in split.iter().enumerate() {
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match hex_to_char(s) {
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Ok(s) => print!("{}", s),
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Err(e) => println!("\nError decoding char '{}' at index {}", e, i),
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}
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let char_vec: Vec<char> = input.chars().collect();
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let hex_char = &char_vec
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.chunks(2)
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.map(|chunk| chunk.iter().collect::<String>())
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.collect::<Vec<_>>();
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// Printing the string in Ascii format - for decoding example
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print!("Input string in ASCII is : « ");
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for (i, s) in hex_char.into_iter().enumerate() {
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match hex_to_char(s) {
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Ok(s) => input_str.push(s),
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Err(e) => println!("\nError decoding char '{}' at index {}", e, i),
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}
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println!();
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}
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println!(" »");
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// Now we can unroll the base64 algorithm
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// We need to : http://www.herongyang.com/Encoding/Base64-Encoding-Algorithm.html
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// Convert hex_char : Vec<String> into Vec<u8>
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// Warning: Panic if not base16
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// See this with .map_err if we need to improve :
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// https://play.rust-lang.org/?version=stable&mode=debug&edition=2015&gist=e241493d100ecaadac3c99f37d0f766f
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let hex: Vec<u8> = hex_char
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.into_iter()
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.map(|i| u8::from_str_radix(i, 16).unwrap())
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.collect();
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println!(" Len is : {}, is it modulo 3-bytes ? {}",
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&hex.len(),
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if &hex.len()%3 == 0 { "true" } else { "false"}
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);
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print!("b64_encode({:?}) ==> ", &input_str);
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// Ugly right ?
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for j in (0..hex.len()).step_by(3) {
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let mut arr = [0u8;4];
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// Must handle Padding here !
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// Index will be out of bound
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// Find a way in rust to detect that ? or just compute here.
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// Si padding 1 = '=' + arr[3] = 0
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// Si padding 2 = '==' + arr[3] & arr[4] = 0
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arr[0] = 0;
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for i in 0..3 {
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arr[i+1] = hex[i+j];
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}
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let tmp = u32::from_be_bytes(arr);
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let tmp1:usize = ((tmp>>18) & 0x3F).try_into().unwrap();
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let tmp2:usize = ((tmp>>12) & 0x3F).try_into().unwrap();
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// If this fail we need to PAD '=='
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let tmp3:usize = ((tmp>>6) & 0x3F).try_into().unwrap();
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// If this fail we need to PAD '='
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let tmp4:usize = ((tmp) & 0x3F).try_into().unwrap();
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print!("{}", BASE64_TABLE[tmp1]);
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print!("{}", BASE64_TABLE[tmp2]);
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print!("{}", BASE64_TABLE[tmp3]);
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print!("{}", BASE64_TABLE[tmp4]);
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}
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println!();
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}
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