src/implementation/fibonacci.rs

0001 // Copyright 2017  Jos van den Oever <jos@vandenoever.info>
0002 //
0003 // This program is free software; you can redistribute it and/or
0004 // modify it under the terms of the GNU General Public License as
0005 // published by the Free Software Foundation; either version 2 of
0006 // the License or (at your option) version 3 or any later version
0007 // accepted by the membership of KDE e.V. (or its successor approved
0008 // by the membership of KDE e.V.), which shall act as a proxy
0009 // defined in Section 14 of version 3 of the license.
0010 //
0011 // This program is distributed in the hope that it will be useful,
0012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
0013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0014 // GNU General Public License for more details.
0015 //
0016 // You should have received a copy of the GNU General Public License
0017 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
0018
0019 use std::thread;
0020 use interface::*;
0021 use std::sync::atomic::AtomicUsize;
0022 use std::sync::atomic::Ordering;
0023 use std::sync::Arc;
0024
0025 fn fibonacci(input: u32) -> usize {
0026     if input <= 1 {
0027         return input as usize;
0028     }
0029     let mut i = 0;
0030     let mut sum = 0;
0031     let mut last = 0;
0032     let mut cur = 1;
0033     while i < input - 1 {
0034         sum = last + cur;
0035         last = cur;
0036         cur = sum;
0037         i += 1;
0038     }
0039     sum
0040 }
0041
0042 pub struct Fibonacci {
0043     emit: FibonacciEmitter,
0044     input: u32,
0045     result: Arc<AtomicUsize>,
0046 }
0047
0048 impl FibonacciTrait for Fibonacci {
0049     fn new(emit: FibonacciEmitter) -> Fibonacci {
0050         Fibonacci {
0051             emit,
0052             input: 0,
0053             result: Arc::new(AtomicUsize::new(0)),
0054         }
0055     }
0056     fn emit(&mut self) -> &mut FibonacciEmitter {
0057         &mut self.emit
0058     }
0059     fn input(&self) -> u32 {
0060         self.input
0061     }
0062     fn set_input(&mut self, value: u32) {
0063         self.input = value;
0064         self.emit.input_changed();
0065         let mut emit = self.emit.clone();
0066         let result = self.result.clone();
0067         result.swap(0, Ordering::SeqCst);
0068         emit.result_changed();
0069         thread::spawn(move || {
0070             let r = fibonacci(value);
0071             result.swap(r, Ordering::SeqCst);
0072             emit.result_changed();
0073         });
0074     }
0075     fn result(&self) -> u64 {
0076         self.result.fetch_add(0, Ordering::SeqCst) as u64
0077     }
0078 }
0079
0080 pub struct FibonacciList {
0081     emit: FibonacciListEmitter,
0082 }
0083
0084 impl FibonacciListTrait for FibonacciList {
0085     fn new(emit: FibonacciListEmitter, _: FibonacciListList) -> FibonacciList {
0086         FibonacciList {
0087             emit,
0088         }
0089     }
0090     fn emit(&mut self) -> &mut FibonacciListEmitter {
0091         &mut self.emit
0092     }
0093     fn row_count(&self) -> usize {
0094         93
0095     }
0096     fn row(&self, row: usize) -> u64 {
0097         row as u64 + 1
0098     }
0099     fn fibonacci_number(&self, row: usize) -> u64 {
0100         fibonacci(row as u32 + 1) as u64
0101     }
0102 }