mirror of
https://github.com/pezkuwichain/pezkuwi-subxt.git
synced 2026-04-27 04:37:57 +00:00
Shawn Tabrizi
78 lines
2.2 KiB
Rust
78 lines
2.2 KiB
Rust
// Copyright 2019-2020 Parity Technologies (UK) Ltd.
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// This file is part of Substrate.
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// Substrate is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Substrate is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Substrate. If not, see <http://www.gnu.org/licenses/>.
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//! # Running
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//! Running this fuzzer can be done with `cargo hfuzz run rational128`. `honggfuzz` CLI options can
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//! be used by setting `HFUZZ_RUN_ARGS`, such as `-n 4` to use 4 threads.
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//!
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//! # Debugging a panic
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//! Once a panic is found, it can be debugged with
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//! `cargo hfuzz run-debug rational128 hfuzz_workspace/rational128/*.fuzz`.
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//!
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//! # More infomation
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//! More information about `honggfuzz` can be found
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//! [here](https://docs.rs/honggfuzz/).
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use honggfuzz::fuzz;
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use sp_arithmetic::{helpers_128bit::multiply_by_rational, traits::Zero};
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fn main() {
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loop {
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fuzz!(|data: ([u8; 16], [u8; 16], [u8; 16])| {
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let (a_bytes, b_bytes, c_bytes) = data;
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let (a, b, c) = (
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u128::from_be_bytes(a_bytes),
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u128::from_be_bytes(b_bytes),
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u128::from_be_bytes(c_bytes),
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);
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println!("++ Equation: {} * {} / {}", a, b, c);
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// The point of this fuzzing is to make sure that `multiply_by_rational` is 100%
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// accurate as long as the value fits in a u128.
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if let Ok(result) = multiply_by_rational(a, b, c) {
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let truth = mul_div(a, b, c);
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if result != truth && result != truth + 1 {
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println!("++ Expected {}", truth);
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println!("+++++++ Got {}", result);
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panic!();
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}
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}
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})
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}
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}
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fn mul_div(a: u128, b: u128, c: u128) -> u128 {
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use primitive_types::U256;
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if a.is_zero() {
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return Zero::zero();
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}
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let c = c.max(1);
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// e for extended
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let ae: U256 = a.into();
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let be: U256 = b.into();
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let ce: U256 = c.into();
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let r = ae * be / ce;
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if r > u128::max_value().into() {
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a
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} else {
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r.as_u128()
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}
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}
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