Roc Toolkit internal modules
Roc Toolkit: real-time audio streaming
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optional.h
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1/*
2 * Copyright (c) 2020 Roc Streaming authors
3 *
4 * This Source Code Form is subject to the terms of the Mozilla Public
5 * License, v. 2.0. If a copy of the MPL was not distributed with this
6 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
7 */
8
9//! @file roc_core/optional.h
10//! @brief Optionally constructed object.
11
12#ifndef ROC_CORE_OPTIONAL_H_
13#define ROC_CORE_OPTIONAL_H_
14
16#include "roc_core/attributes.h"
18#include "roc_core/panic.h"
19#include "roc_core/stddefs.h"
20
21namespace roc {
22namespace core {
23
24//! Optionally constructed object.
25template <class T, size_t Size = sizeof(T)> class Optional : public NonCopyable<> {
26public:
27 Optional()
28 : ptr_(NULL) {
29 }
30
31 ~Optional() {
32 if (ptr_) {
33 ptr_->~T();
34 }
35 }
36
37 //! Set pointer to the newly created object, destroy old pointed object if set.
38 //! @pre
39 //! @p ptr should be returned by associated placement new.
40 void reset(T* ptr = NULL) {
41 if (ptr_) {
42 ptr_->~T();
43 }
44 if (ptr && (void*)ptr != storage_.memory()) {
45 roc_panic("optional: attempt to set incorrect object");
46 }
47 ptr_ = ptr;
48 }
49
50 //! Get underlying object.
51 T* get() const {
52 return ptr_;
53 }
54
55 //! Get underlying object.
56 T* operator->() const {
57 if (ptr_ == NULL) {
58 roc_panic("optional: attempt to dereference uninitialized object");
59 }
60 return ptr_;
61 }
62
63 //! Get underlying reference.
64 T& operator*() const {
65 if (ptr_ == NULL) {
66 roc_panic("optional: attempt to dereference uninitialized object");
67 }
68 return *ptr_;
69 }
70
71 //! Convert to bool.
72 operator const struct unspecified_bool *() const {
73 return (const unspecified_bool*)ptr_;
74 }
75
76 //! Get object memory.
77 //! @pre
78 //! Should be called before object is actually allocated.
80 if (ptr_) {
81 roc_panic("optional: attempt to get memory after the object was created");
82 }
83 return storage_.memory();
84 }
85
86private:
87 T* ptr_;
88 AlignedStorage<Size> storage_;
89};
90
91} // namespace core
92} // namespace roc
93
94//! Placement new for core::Optional.
95//! @note
96//! nothrow forces compiler to check for NULL return value before calling ctor.
97template <class T, size_t Size>
98inline void* operator new(size_t size, roc::core::Optional<T, Size>& opt) throw() {
99 roc_panic_if_not(size <= Size);
100 return opt.unallocated_memory();
101}
102
103//! Placement delete for core::Optional.
104//! @note
105//! Compiler calls this if ctor throws in a placement new expression.
106template <class T, size_t Size>
107inline void operator delete(void*, roc::core::Optional<T, Size>&) throw() {
108}
109
110#endif // ROC_CORE_OPTIONAL_H_
Aligned storage.
Compiler attributes.
Base class for non-copyable objects.
Definition noncopyable.h:23
Optionally constructed object.
Definition optional.h:25
T * operator->() const
Get underlying object.
Definition optional.h:56
T & operator*() const
Get underlying reference.
Definition optional.h:64
T * get() const
Get underlying object.
Definition optional.h:51
void reset(T *ptr=NULL)
Set pointer to the newly created object, destroy old pointed object if set.
Definition optional.h:40
void * unallocated_memory()
Get object memory.
Definition optional.h:79
Shared ownership intrusive pointer.
Definition shared_ptr.h:32
Root namespace.
Non-copyable object.
Panic.
#define roc_panic_if_not(x)
Panic if condition is false.
Definition panic.h:37
#define roc_panic(...)
Print error message and terminate program gracefully.
Definition panic.h:50
Commonly used types and functions.