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
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
//===--- ArrayRef.h - Array Reference Wrapper -------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_ARRAYREF_H
#define LLVM_ADT_ARRAYREF_H
#include "llvm/ADT/SmallVector.h"
#include <vector>
namespace llvm {
class APInt;
/// ArrayRef - Represent a constant reference to an array (0 or more elements
/// consecutively in memory), i.e. a start pointer and a length. It allows
/// various APIs to take consecutive elements easily and conveniently.
///
/// This class does not own the underlying data, it is expected to be used in
/// situations where the data resides in some other buffer, whose lifetime
/// extends past that of the StringRef. For this reason, it is not in general
/// safe to store a ArrayRef.
///
/// This is intended to be trivially copyable, so it should be passed by
/// value.
template<typename T>
class ArrayRef {
public:
typedef const T *iterator;
typedef const T *const_iterator;
typedef size_t size_type;
private:
/// The start of the array, in an external buffer.
const T *Data;
/// The number of elements.
size_t Length;
public:
/// @name Constructors
/// @{
/// Construct an empty ArrayRef.
/*implicit*/ ArrayRef() : Data(0), Length(0) {}
/// Construct an ArrayRef from a single element.
/*implicit*/ ArrayRef(const T &OneElt)
: Data(&OneElt), Length(1) {}
/// Construct an ArrayRef from a pointer and length.
/*implicit*/ ArrayRef(const T *data, size_t length)
: Data(data), Length(length) {}
/// Construct an ArrayRef from a SmallVector.
/*implicit*/ ArrayRef(const SmallVectorImpl<T> &Vec)
: Data(Vec.data()), Length(Vec.size()) {}
/// Construct an ArrayRef from a std::vector.
/*implicit*/ ArrayRef(const std::vector<T> &Vec)
: Data(Vec.empty() ? (T*)0 : &Vec[0]), Length(Vec.size()) {}
/// Construct an ArrayRef from a C array.
template <size_t N>
/*implicit*/ ArrayRef(const T (&Arr)[N])
: Data(Arr), Length(N) {}
/// @}
/// @name Simple Operations
/// @{
iterator begin() const { return Data; }
iterator end() const { return Data + Length; }
/// empty - Check if the array is empty.
bool empty() const { return Length == 0; }
const T *data() const { return Data; }
/// size - Get the array size.
size_t size() const { return Length; }
/// front - Get the first element.
const T &front() const {
assert(!empty());
return Data[0];
}
/// back - Get the last element.
const T &back() const {
assert(!empty());
return Data[Length-1];
}
/// slice(n) - Chop off the first N elements of the array.
ArrayRef<T> slice(unsigned N) {
assert(N <= size() && "Invalid specifier");
return ArrayRef<T>(data()+N, size()-N);
}
/// slice(n, m) - Chop off the first N elements of the array, and keep M
/// elements in the array.
ArrayRef<T> slice(unsigned N, unsigned M) {
assert(N+M <= size() && "Invalid specifier");
return ArrayRef<T>(data()+N, M);
}
/// @}
/// @name Operator Overloads
/// @{
const T &operator[](size_t Index) const {
assert(Index < Length && "Invalid index!");
return Data[Index];
}
/// @}
/// @name Expensive Operations
/// @{
std::vector<T> vec() const {
return std::vector<T>(Data, Data+Length);
}
/// @}
};
// ArrayRefs can be treated like a POD type.
template <typename T> struct isPodLike;
template <typename T> struct isPodLike<ArrayRef<T> > {
static const bool value = true;
};
}
#endif
|
