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#![no_std]
#[doc(hidden)]
#[macro_export]
macro_rules! require_even_number_digits {
($e:expr) => {
let _: $crate::Even<[(); $e % 2]>;
};
}
pub type Even<T> =
<<T as HexStringLength>::Marker as LengthIsEvenNumberOfHexDigits>::Check;
pub enum IsEvenNumberofDigits {}
pub enum IsOddNumberofDigits {}
pub trait HexStringLength {
type Marker;
}
impl HexStringLength for [(); 0] {
type Marker = IsEvenNumberofDigits;
}
impl HexStringLength for [(); 1] {
type Marker = IsOddNumberofDigits;
}
pub trait LengthIsEvenNumberOfHexDigits {
type Check;
}
impl LengthIsEvenNumberOfHexDigits for IsEvenNumberofDigits {
type Check = ();
}
#[macro_export]
macro_rules! hex {
(@string $arg:expr) => {{
const NUM_SPACES: usize = {
let data = $arg.as_bytes();
let mut space_count: usize = 0;
let mut char_index: usize = 0;
while char_index < data.len() {
if data[char_index] == b' ' {
space_count += 1;
}
char_index += 1;
}
space_count
};
const NUM_UNDERSCORES: usize = {
let data = $arg.as_bytes();
let mut underscore_count: usize = 0;
let mut char_index: usize = 0;
while char_index < data.len() {
if data[char_index] == b'_' {
underscore_count += 1;
}
char_index += 1;
}
underscore_count
};
const NUM_QUOTES: usize = {
let data = $arg.as_bytes();
let mut underscore_count: usize = 0;
let mut char_index: usize = 0;
while char_index < data.len() {
if data[char_index] == b'"' {
underscore_count += 1;
}
char_index += 1;
}
underscore_count
};
const NUM_SKIPPED: usize = NUM_SPACES + NUM_UNDERSCORES + NUM_QUOTES;
$crate::require_even_number_digits!($arg.len() - NUM_SKIPPED);
const ARRAY_LENGTH: usize = ($arg.len() - NUM_SKIPPED) / 2;
const RESULT: [u8; ARRAY_LENGTH] = {
const fn always_true() -> bool {
true
}
const fn to_ordinal(input: u8) -> u8 {
match input {
b'0'..=b'9' => input - b'0',
b'A'..=b'F' => input - b'A' + 10,
b'a'..=b'f' => input - b'a' + 10,
_ => {
["Invalid hex digit."][(always_true() as usize)];
0
}
}
}
const fn convert(s: &str) -> [u8; ARRAY_LENGTH] {
let s = s.as_bytes();
let mut data = [0u8; ARRAY_LENGTH];
let mut data_index: usize = 0;
let mut char_index: usize = 0;
let string_length = s.len();
while data_index < string_length && char_index + 1 < string_length {
if s[char_index] != b' ' && s[char_index] != b'_' && s[char_index] != b'"' {
let mut next_index = char_index + 1;
while next_index < string_length && (s[next_index] == b' ' || s[next_index] == b'_' || s[next_index] == b'"') {
next_index += 1;
}
data[data_index] = to_ordinal(s[char_index]) * 16 + to_ordinal(s[next_index]);
char_index = next_index + 1;
data_index += 1;
} else {
char_index += 1;
}
}
data
}
convert($arg)
};
RESULT
}};
($($tt:tt)*) => {
hex!(@string stringify!($($tt)*))
};
}
#[cfg(test)]
mod tests {
use super::hex;
#[test]
fn test_leading_zeros() {
assert_eq!(hex!("01020304"), [1, 2, 3, 4]);
}
#[test]
fn test_alphanumeric_lower() {
assert_eq!(hex!("a1b2c3d4"), [0xA1, 0xB2, 0xC3, 0xD4]);
}
#[test]
fn test_alphanumeric_upper() {
assert_eq!(hex!("E5E69092"), [0xE5, 0xE6, 0x90, 0x92]);
}
#[test]
fn test_alphanumeric_mixed() {
assert_eq!(hex!("0a0B0C0d"), [10, 11, 12, 13]);
}
#[test]
fn test_leading_zeros_space() {
assert_eq!(hex!("01 02 03 04"), [1, 2, 3, 4]);
}
#[test]
fn test_alphanumeric_lower_space() {
assert_eq!(hex!("a1 b2 c3 d4"), [0xA1, 0xB2, 0xC3, 0xD4]);
}
#[test]
fn test_alphanumeric_upper_space() {
assert_eq!(hex!("E5 E6 90 92"), [0xE5, 0xE6, 0x90, 0x92]);
}
#[test]
fn test_alphanumeric_mixed_space() {
assert_eq!(hex!("0a 0B 0C 0d"), [10, 11, 12, 13]);
}
#[test]
fn test_no_quotes() {
assert_eq!(hex!(a0 0B 0C 0d), [0xa0, 11, 12, 13]);
}
#[test]
fn test_weird_quotes() {
assert_eq!(hex!(a0 "0b" 0C 0d), [0xa0, 11, 12, 13]);
}
#[test]
fn test_no_quotes_start_with_zero() {
assert_eq!(hex!(0A 0B 0C0d), [10, 11, 12, 13]);
}
#[test]
fn test_underscores() {
assert_eq!(hex!(0A_0B_0C 0d), [10, 11, 12, 13]);
}
#[test]
fn test_mixed_no_quotes() {
assert_eq!(hex!(1a 0b_0C 0d), [0x1a, 11, 12, 13]);
}
}