const_random_macro/
lib.rs

1#[allow(unused_extern_crates)]
2extern crate proc_macro;
3
4use proc_macro::*;
5use std::iter::once;
6mod span;
7use crate::span::{gen_random_bytes, gen_random};
8
9
10/// Create a TokenStream of an identifier out of a string
11fn ident(ident: &str) -> TokenStream {
12    TokenTree::from(Ident::new(ident, Span::call_site())).into()
13}
14
15#[proc_macro]
16pub fn const_random(input: TokenStream) -> TokenStream {
17    match &input.to_string()[..] {
18        "u8" => TokenTree::from(Literal::u8_suffixed(gen_random())).into(),
19        "u16" => TokenTree::from(Literal::u16_suffixed(gen_random())).into(),
20        "u32" => TokenTree::from(Literal::u32_suffixed(gen_random())).into(),
21        "u64" => TokenTree::from(Literal::u64_suffixed(gen_random())).into(),
22        "u128" => TokenTree::from(Literal::u128_suffixed(gen_random())).into(),
23        "i8" => TokenTree::from(Literal::i8_suffixed(gen_random())).into(),
24        "i16" => TokenTree::from(Literal::i16_suffixed(gen_random())).into(),
25        "i32" => TokenTree::from(Literal::i32_suffixed(gen_random())).into(),
26        "i64" => TokenTree::from(Literal::i64_suffixed(gen_random())).into(),
27        "i128" => TokenTree::from(Literal::i128_suffixed(gen_random())).into(),
28        "usize" => {
29            let value: TokenStream = TokenTree::from(Literal::u128_suffixed(gen_random())).into();
30            let type_cast: TokenStream = [value, ident("as"), ident("usize")]
31                .iter()
32                .cloned()
33                .collect();
34            TokenTree::from(Group::new(Delimiter::Parenthesis, type_cast)).into()
35        }
36        "isize" => {
37            let value: TokenStream = TokenTree::from(Literal::i128_suffixed(gen_random())).into();
38            let type_cast: TokenStream = [value, ident("as"), ident("isize")]
39                .iter()
40                .cloned()
41                .collect();
42            TokenTree::from(Group::new(Delimiter::Parenthesis, type_cast)).into()
43        }
44        byte_array if byte_array.starts_with("[u8 ; ") && byte_array.ends_with(']')=> {
45            let len = byte_array[6..byte_array.len()-1].parse().unwrap();
46            let mut random_bytes = vec![0; len];
47            gen_random_bytes(&mut random_bytes);
48            let array_parts: TokenStream = random_bytes.into_iter().flat_map(|byte|  {
49                let val = TokenTree::from(Literal::u8_suffixed(byte));
50                let comma = TokenTree::from(Punct::new(',', Spacing::Alone));
51                once(val).chain(once(comma))
52            }).collect();
53            TokenTree::from(Group::new(Delimiter::Bracket, array_parts)).into()
54        }
55        _ => panic!("Invalid type"),
56    }
57}
const_random_macro/lib.rs

const_random_macro/
lib.rs
