Electroneum
apply_permutation.h
Go to the documentation of this file.
1 // Copyright (c) 2017-2019, The Monero Project
2 //
3 // All rights reserved.
4 //
5 // Redistribution and use in source and binary forms, with or without modification, are
6 // permitted provided that the following conditions are met:
7 //
8 // 1. Redistributions of source code must retain the above copyright notice, this list of
9 // conditions and the following disclaimer.
10 //
11 // 2. Redistributions in binary form must reproduce the above copyright notice, this list
12 // of conditions and the following disclaimer in the documentation and/or other
13 // materials provided with the distribution.
14 //
15 // 3. Neither the name of the copyright holder nor the names of its contributors may be
16 // used to endorse or promote products derived from this software without specific
17 // prior written permission.
18 //
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
20 // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
21 // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
22 // THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
24 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
26 // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
27 // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 //
29 // Most of this file is originally copyright (c) 2017 Raymond Chen, Microsoft
30 // This algorithm is adapted from Raymond Chen's code:
31 // https://blogs.msdn.microsoft.com/oldnewthing/20170109-00/?p=95145
32 
33 #pragma once
34 
35 #include <vector>
36 #include <functional>
37 #include "misc_log_ex.h"
38 
39 namespace tools
40 {
41 
42 template<typename F>
43 void apply_permutation(std::vector<size_t> permutation, const F &swap)
44 {
45  //sanity check
46  for (size_t n = 0; n < permutation.size(); ++n)
47  CHECK_AND_ASSERT_THROW_MES(std::find(permutation.begin(), permutation.end(), n) != permutation.end(), "Bad permutation");
48 
49  for (size_t i = 0; i < permutation.size(); ++i)
50  {
51  size_t current = i;
52  while (i != permutation[current])
53  {
54  size_t next = permutation[current];
55  swap(current, next);
56  permutation[current] = current;
57  current = next;
58  }
59  permutation[current] = current;
60  }
61 }
62 
63 template<typename T>
64 void apply_permutation(const std::vector<size_t> &permutation, std::vector<T> &v)
65 {
66  CHECK_AND_ASSERT_THROW_MES(permutation.size() == v.size(), "Mismatched vector sizes");
67  apply_permutation(permutation, [&v](size_t i0, size_t i1){ std::swap(v[i0], v[i1]); });
68 }
69 
70 }
#define CHECK_AND_ASSERT_THROW_MES(expr, message)
Definition: misc_log_ex.h:173
void apply_permutation(std::vector< size_t > permutation, const F &swap)
Various Tools.
Definition: tools.cpp:31
#define F(s)