blob: 8a93091f0ebfb1e8531017eaa15082e01e52067e (
plain)
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
|
//===-- Holds an expected or unexpected value -------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC___SUPPORT_CPP_EXPECTED_H
#define LLVM_LIBC_SRC___SUPPORT_CPP_EXPECTED_H
#include "src/__support/macros/attributes.h"
#include "src/__support/macros/config.h"
namespace LIBC_NAMESPACE_DECL {
namespace cpp {
// This is used to hold an unexpected value so that a different constructor is
// selected.
template <class T> class unexpected {
T value;
public:
LIBC_INLINE constexpr explicit unexpected(T value) : value(value) {}
LIBC_INLINE constexpr T error() { return value; }
};
template <class T> explicit unexpected(T) -> unexpected<T>;
template <class T, class E> class expected {
union {
T exp;
E unexp;
};
bool is_expected;
public:
LIBC_INLINE constexpr expected(T exp) : exp(exp), is_expected(true) {}
LIBC_INLINE constexpr expected(unexpected<E> unexp)
: unexp(unexp.error()), is_expected(false) {}
LIBC_INLINE constexpr bool has_value() const { return is_expected; }
LIBC_INLINE constexpr T &value() { return exp; }
LIBC_INLINE constexpr E &error() { return unexp; }
LIBC_INLINE constexpr const T &value() const { return exp; }
LIBC_INLINE constexpr const E &error() const { return unexp; }
LIBC_INLINE constexpr operator bool() const { return is_expected; }
LIBC_INLINE constexpr T &operator*() { return exp; }
LIBC_INLINE constexpr const T &operator*() const { return exp; }
LIBC_INLINE constexpr T *operator->() { return &exp; }
LIBC_INLINE constexpr const T *operator->() const { return &exp; }
};
} // namespace cpp
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SRC___SUPPORT_CPP_EXPECTED_H
|
