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extern crate proc_macro;
use quote::quote;
use syn::{parse_macro_input, Error as SynError};
use ckb_occupied_capacity_core::Capacity;
#[proc_macro]
pub fn capacity_bytes(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let input = parse_macro_input!(input as syn::LitInt);
let expanded = {
if input.suffix().is_empty() {
input
.base10_parse::<usize>()
.map_err(|_| {
SynError::new(
input.span(),
"the input should be a positive integer literal",
)
})
.and_then(|value| {
Capacity::bytes(value)
.map_err(|_| SynError::new(input.span(), "the input capacity is overflow"))
.map(|value| {
let shannons =
syn::LitInt::new(&value.as_u64().to_string(), input.span());
quote!(Capacity::shannons(#shannons))
})
})
} else {
Err(SynError::new(
input.span(),
"the input should be an integer literal without any suffix",
))
}
.unwrap_or_else(|err| err.to_compile_error())
};
expanded.into()
}