/src/mozilla-central/dom/xslt/base/txStack.h
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1 | | /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ |
2 | | /* This Source Code Form is subject to the terms of the Mozilla Public |
3 | | * License, v. 2.0. If a copy of the MPL was not distributed with this |
4 | | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
5 | | |
6 | | #ifndef txStack_h___ |
7 | | #define txStack_h___ |
8 | | |
9 | | #include "nsTArray.h" |
10 | | |
11 | | class txStack : private nsTArray<void*> |
12 | | { |
13 | | public: |
14 | | /** |
15 | | * Returns the specified object from the top of this stack, |
16 | | * without removing it from the stack. |
17 | | * |
18 | | * @return a pointer to the object that is the top of this stack. |
19 | | */ |
20 | | inline void* peek() |
21 | 0 | { |
22 | 0 | NS_ASSERTION(!isEmpty(), "peeking at empty stack"); |
23 | 0 | return !isEmpty() ? ElementAt(Length() - 1) : nullptr; |
24 | 0 | } |
25 | | |
26 | | /** |
27 | | * Adds the specified object to the top of this stack. |
28 | | * |
29 | | * @param obj a pointer to the object that is to be added to the |
30 | | * top of this stack. |
31 | | */ |
32 | | inline nsresult push(void* aObject) |
33 | 0 | { |
34 | 0 | return AppendElement(aObject) ? NS_OK : NS_ERROR_OUT_OF_MEMORY; |
35 | 0 | } |
36 | | |
37 | | /** |
38 | | * Removes and returns the specified object from the top of this |
39 | | * stack. |
40 | | * |
41 | | * @return a pointer to the object that was the top of this stack. |
42 | | */ |
43 | | inline void* pop() |
44 | 0 | { |
45 | 0 | void* object = nullptr; |
46 | 0 | NS_ASSERTION(!isEmpty(), "popping from empty stack"); |
47 | 0 | if (!isEmpty()) |
48 | 0 | { |
49 | 0 | const uint32_t count = Length() - 1; |
50 | 0 | object = ElementAt(count); |
51 | 0 | RemoveElementAt(count); |
52 | 0 | } |
53 | 0 | return object; |
54 | 0 | } |
55 | | |
56 | | /** |
57 | | * Returns true if there are no objects in the stack. |
58 | | * |
59 | | * @return true if there are no objects in the stack. |
60 | | */ |
61 | | inline bool isEmpty() |
62 | 0 | { |
63 | 0 | return IsEmpty(); |
64 | 0 | } |
65 | | |
66 | | /** |
67 | | * Returns the number of elements in the Stack. |
68 | | * |
69 | | * @return the number of elements in the Stack. |
70 | | */ |
71 | | inline int32_t size() |
72 | 0 | { |
73 | 0 | return Length(); |
74 | 0 | } |
75 | | |
76 | | private: |
77 | | friend class txStackIterator; |
78 | | }; |
79 | | |
80 | | class txStackIterator |
81 | | { |
82 | | public: |
83 | | /** |
84 | | * Creates an iterator for the given stack. |
85 | | * |
86 | | * @param aStack the stack to create an iterator for. |
87 | | */ |
88 | | inline |
89 | | explicit txStackIterator(txStack* aStack) : mStack(aStack), |
90 | | mPosition(0) |
91 | 0 | { |
92 | 0 | } |
93 | | |
94 | | /** |
95 | | * Returns true if there is more objects on the stack. |
96 | | * |
97 | | * @return . |
98 | | */ |
99 | | inline bool hasNext() |
100 | 0 | { |
101 | 0 | return (mPosition < mStack->Length()); |
102 | 0 | } |
103 | | |
104 | | /** |
105 | | * Returns the next object pointer from the stack. |
106 | | * |
107 | | * @return . |
108 | | */ |
109 | | inline void* next() |
110 | 0 | { |
111 | 0 | if (mPosition == mStack->Length()) { |
112 | 0 | return nullptr; |
113 | 0 | } |
114 | 0 | return mStack->ElementAt(mPosition++); |
115 | 0 | } |
116 | | |
117 | | private: |
118 | | txStack* mStack; |
119 | | uint32_t mPosition; |
120 | | }; |
121 | | |
122 | | #endif /* txStack_h___ */ |