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extern crate proc_macro;
use proc_macro_hack::proc_macro_hack;
use quote::quote;
use syn::parse_macro_input;
struct Bytes(Vec<u8>);
impl ::std::fmt::Debug for Bytes {
#[inline]
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
let data = &self.0;
write!(f, "&[")?;
if data.len() != 0 {
write!(f, "{:#04x}u8", data[0])?;
for unit in data.iter().skip(1) {
write!(f, ", {:#04x}", unit)?;
}
}
write!(f, "]")
}
}
#[proc_macro_hack]
pub fn u8_slice(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let input = parse_macro_input!(input as syn::LitStr);
let expanded = {
let input = input.value().replace("_", "");
if input.len() < 2 || &input[..2] != "0x" || input.len() % 2 != 0 {
panic!("Input has to be a hexadecimal string with 0x-prefix.");
};
let input_str = &input[2..];
let buffer_len = input_str.len() / 2;
let buffer = if buffer_len != 0 {
let mut buffer = vec![0u8; buffer_len];
faster_hex::hex_decode(input_str.as_bytes(), &mut buffer).unwrap_or_else(|err| {
panic!("Failed to parse the input hexadecimal string: {}", err);
});
buffer
} else {
vec![]
};
let bytes = Bytes(buffer);
let eval_str = format!("{:?}", bytes);
let eval_ts: proc_macro2::TokenStream = eval_str.parse().unwrap_or_else(|_| {
panic!(
"Failed to parse the string \"{}\" to TokenStream.",
eval_str
);
});
quote!(#eval_ts)
};
expanded.into()
}