use crate::Exceptions;
use crate::common::Result;
pub fn calculate_checksum(contents: &str) -> char {
let sum: u32 = contents.chars().map(|c| c as u32).sum();
let remainder = sum % 127;
let diff = 127 - remainder;
if diff != 127 {
diff as u8 as char
} else {
0 as char
}
}
pub fn ascii_to_numeric(contents: &str) -> String {
let mut number = String::with_capacity(contents.chars().count() * 2);
for c in contents.chars().map(|x| x as u32) {
if c >= 27 {
number.push_str(&format!("{:0>2}", (c - 27)));
} else {
number.push_str(&format!("{:0>2}", (c - 17)));
}
}
number
}
pub fn numeric_to_ascii(contents: &str) -> Result<String> {
if contents.len() % 2 != 0 {
return Err(Exceptions::illegal_argument_with(
"Input must contain an even number of characters.",
));
}
let mut ascii = Vec::with_capacity(contents.chars().count() / 2);
let cached_contents: Vec<u8> = contents.chars().map(|c| c as u8).collect();
for (i, chunk) in cached_contents.chunks_exact(2).enumerate() {
let first = chunk[0];
let second = chunk[1];
if second == 88 && (48..=57).contains(&first) {
ascii.push((17 + first - 48) as char);
} else if (48..=57).contains(&second) && (48..=57).contains(&first) {
ascii.push((27 + (first - 48) * 10 + (second - 48)) as char);
} else {
return Err(Exceptions::illegal_argument_with(format!(
"Input contains an invalid character around position {}.",
i * 2
)));
}
}
Ok(ascii.iter().collect())
}
#[test]
fn telepen_checksum_test1() {
let contents = "Hello world!";
let checksum = calculate_checksum(contents);
assert_eq!('\u{1a}', checksum);
}
#[test]
fn telepen_checksum_test2() {
let contents = "ABC123456";
let checksum = calculate_checksum(contents);
assert_eq!('\u{1}', checksum);
}
#[test]
fn telepen_alpha_to_numeric_test() {
let mut ascii = "'=Siu";
let mut result = ascii_to_numeric(ascii);
assert_eq!("1234567890", result);
ascii = "& oe";
result = ascii_to_numeric(ascii);
assert_eq!("11058474", result);
}
#[test]
fn telepen_numeric_to_ascii_test() {
let mut numeric = "1234567890";
let mut result = numeric_to_ascii(numeric).unwrap();
assert_eq!("'=Siu", result);
numeric = "11058474";
result = numeric_to_ascii(numeric).unwrap();
assert_eq!("& oe", result);
}