use std::fmt;
use crate::{Result, Tape, Value};
#[derive(Clone, Copy, Default, Eq, Hash, PartialEq)]
pub struct Tag(pub [u8; 4]);
impl Tag {
pub fn as_str(&self) -> Option<&str> {
match std::str::from_utf8(&self.0[..]) {
Ok(value) if !value.chars().any(char::is_control) => Some(value),
_ => None,
}
}
}
dereference! { Tag::0 => [u8; 4] }
impl fmt::Debug for Tag {
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
match self.as_str() {
Some(value) => write!(formatter, "Tag({value})"),
_ => write!(formatter, "Tag(0x{:08X})", u32::from(*self)),
}
}
}
impl From<u32> for Tag {
#[inline(always)]
fn from(value: u32) -> Self {
Tag(u32::from_be(value).to_ne_bytes())
}
}
impl From<Tag> for u32 {
#[inline(always)]
fn from(tag: Tag) -> Self {
u32::from_be_bytes(tag.0)
}
}
impl Value for Tag {
#[inline(always)]
fn read<T: Tape>(tape: &mut T) -> Result<Self> {
Ok(Tag(tape.take()?))
}
}
#[cfg(test)]
mod tests {
use std::io::Cursor;
use super::Tag;
use crate::Value;
#[test]
fn as_str() {
assert_eq!(Tag(*b"CFF ").as_str(), Some("CFF "));
assert_eq!(Tag(*b"OS/2").as_str(), Some("OS/2"));
assert_eq!(Tag(*b"true").as_str(), Some("true"));
assert_eq!(Tag([0, 1, 0, 0]).as_str(), None);
}
#[test]
fn debug() {
assert_eq!(format!("{:?}", Tag(*b"true")), "Tag(true)");
assert_eq!(format!("{:?}", Tag([0, 1, 0, 0])), "Tag(0x00010000)");
}
#[test]
fn from() {
assert_eq!(Tag(*b"true"), Tag::from(0x74727565));
}
#[test]
fn into() {
assert_eq!(u32::from(Tag(*b"true")), 0x74727565);
}
#[test]
fn read() {
let mut tape = Cursor::new(b"true".to_vec());
assert_eq!(Tag::read(&mut tape).unwrap(), Tag(*b"true"));
}
}