mirror of
https://github.com/pezkuwichain/pezkuwi-subxt.git
synced 2026-04-26 22:47:56 +00:00
Benjamin Kampmann
79 lines
2.2 KiB
Rust
79 lines
2.2 KiB
Rust
// This file is part of Substrate.
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// Copyright (C) 2019-2020 Parity Technologies (UK) Ltd.
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// SPDX-License-Identifier: Apache-2.0
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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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 information
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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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