1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
|
/*
* Copyright (C) 2024 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <wtf/IndexedRange.h>
namespace WTF {
template<typename IteratorA, typename IteratorB> class ZippedRangeIterator {
public:
ZippedRangeIterator(IteratorA&& iteratorA, IteratorB&& iteratorB)
: m_iteratorA(WTFMove(iteratorA))
, m_iteratorB(WTFMove(iteratorB))
{
}
ZippedRangeIterator& operator++()
{
++m_iteratorA;
++m_iteratorB;
return *this;
}
auto operator*()
{
return std::pair<decltype(*m_iteratorA), decltype(*m_iteratorB)> { *m_iteratorA, *m_iteratorB };
}
bool operator==(const ZippedRangeIterator& other) const
{
// To ensure that we compare equal to end() even when we iterate two
// collections of different sizes, we need to compare both A and B.
// (Otherwise comparing either A or B would be sufficient, since they
// increment in lockstep.)
return m_iteratorA == other.m_iteratorA || m_iteratorB == other.m_iteratorB;
}
private:
IteratorA m_iteratorA;
IteratorB m_iteratorB;
};
template<typename Iterator>
class ZippedRange {
public:
template<typename CollectionA, typename CollectionB>
ZippedRange(CollectionA&& collectionA, CollectionB&& collectionB)
: m_begin(boundsCheckedBegin(std::forward<CollectionA>(collectionA)), boundsCheckedBegin(std::forward<CollectionB>(collectionB)))
, m_end(boundsCheckedEnd(std::forward<CollectionA>(collectionA)), boundsCheckedEnd(std::forward<CollectionB>(collectionB)))
{
// Prevent use after destruction of a returned temporary.
static_assert(std::ranges::borrowed_range<CollectionA>);
static_assert(std::ranges::borrowed_range<CollectionB>);
}
auto begin() { return m_begin; }
auto end() { return m_end; }
private:
Iterator m_begin;
Iterator m_end;
};
// Usage: for (auto [ valueA, valueB ] : zippedRange(collectionA, collectionB)) { ... }
template<typename CollectionA, typename CollectionB> auto zippedRange(CollectionA&& collectionA, CollectionB&& collectionB)
{
using Iterator = ZippedRangeIterator<decltype(boundsCheckedBegin(std::forward<CollectionA>(collectionA))), decltype(boundsCheckedBegin(std::forward<CollectionB>(collectionB)))>;
return ZippedRange<Iterator>(std::forward<CollectionA>(collectionA), std::forward<CollectionB>(collectionB));
}
} // namespace WTF
using WTF::zippedRange;
|
