1 // Tencent is pleased to support the open source community by making RapidJSON available.
2 //
3 // Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
4 //
5 // Licensed under the MIT License (the "License"); you may not use this file except
6 // in compliance with the License. You may obtain a copy of the License at
7 //
8 // http://opensource.org/licenses/MIT
9 //
10 // Unless required by applicable law or agreed to in writing, software distributed
11 // under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
12 // CONDITIONS OF ANY KIND, either express or implied. See the License for the
13 // specific language governing permissions and limitations under the License.
14 
15 #ifndef RAPIDJSON_STRINGBUFFER_H_
16 #define RAPIDJSON_STRINGBUFFER_H_
17 
18 #include "stream.h"
19 #include "internal/stack.h"
20 
21 #if RAPIDJSON_HAS_CXX11_RVALUE_REFS
22 #include <utility> // std::move
23 #endif
24 
25 #include "internal/stack.h"
26 
27 #if defined(__clang__)
28 RAPIDJSON_DIAG_PUSH
29 RAPIDJSON_DIAG_OFF(c++98-compat)
30 #endif
31 
32 RAPIDJSON_NAMESPACE_BEGIN
33 
34 //! Represents an in-memory output stream.
35 /*!
36     \tparam Encoding Encoding of the stream.
37     \tparam Allocator type for allocating memory buffer.
38     \note implements Stream concept
39 */
40 template <typename Encoding, typename Allocator = CrtAllocator>
41 class GenericStringBuffer {
42 public:
43     typedef typename Encoding::Ch Ch;
44 
stack_(allocator,capacity)45     GenericStringBuffer(Allocator* allocator = 0, size_t capacity = kDefaultCapacity) : stack_(allocator, capacity) {}
46 
47 #if RAPIDJSON_HAS_CXX11_RVALUE_REFS
GenericStringBuffer(GenericStringBuffer && rhs)48     GenericStringBuffer(GenericStringBuffer&& rhs) : stack_(std::move(rhs.stack_)) {}
49     GenericStringBuffer& operator=(GenericStringBuffer&& rhs) {
50         if (&rhs != this)
51             stack_ = std::move(rhs.stack_);
52         return *this;
53     }
54 #endif
55 
Put(Ch c)56     void Put(Ch c) { *stack_.template Push<Ch>() = c; }
PutUnsafe(Ch c)57     void PutUnsafe(Ch c) { *stack_.template PushUnsafe<Ch>() = c; }
Flush()58     void Flush() {}
59 
Clear()60     void Clear() { stack_.Clear(); }
ShrinkToFit()61     void ShrinkToFit() {
62         // Push and pop a null terminator. This is safe.
63         *stack_.template Push<Ch>() = '\0';
64         stack_.ShrinkToFit();
65         stack_.template Pop<Ch>(1);
66     }
67 
Reserve(size_t count)68     void Reserve(size_t count) { stack_.template Reserve<Ch>(count); }
Push(size_t count)69     Ch* Push(size_t count) { return stack_.template Push<Ch>(count); }
PushUnsafe(size_t count)70     Ch* PushUnsafe(size_t count) { return stack_.template PushUnsafe<Ch>(count); }
Pop(size_t count)71     void Pop(size_t count) { stack_.template Pop<Ch>(count); }
72 
GetString()73     const Ch* GetString() const {
74         // Push and pop a null terminator. This is safe.
75         *stack_.template Push<Ch>() = '\0';
76         stack_.template Pop<Ch>(1);
77 
78         return stack_.template Bottom<Ch>();
79     }
80 
81     //! Get the size of string in bytes in the string buffer.
GetSize()82     size_t GetSize() const { return stack_.GetSize(); }
83 
84     //! Get the length of string in Ch in the string buffer.
GetLength()85     size_t GetLength() const { return stack_.GetSize() / sizeof(Ch); }
86 
87     static const size_t kDefaultCapacity = 256;
88     mutable internal::Stack<Allocator> stack_;
89 
90 private:
91     // Prohibit copy constructor & assignment operator.
92     GenericStringBuffer(const GenericStringBuffer&);
93     GenericStringBuffer& operator=(const GenericStringBuffer&);
94 };
95 
96 //! String buffer with UTF8 encoding
97 typedef GenericStringBuffer<UTF8<> > StringBuffer;
98 
99 template<typename Encoding, typename Allocator>
PutReserve(GenericStringBuffer<Encoding,Allocator> & stream,size_t count)100 inline void PutReserve(GenericStringBuffer<Encoding, Allocator>& stream, size_t count) {
101     stream.Reserve(count);
102 }
103 
104 template<typename Encoding, typename Allocator>
PutUnsafe(GenericStringBuffer<Encoding,Allocator> & stream,typename Encoding::Ch c)105 inline void PutUnsafe(GenericStringBuffer<Encoding, Allocator>& stream, typename Encoding::Ch c) {
106     stream.PutUnsafe(c);
107 }
108 
109 //! Implement specialized version of PutN() with memset() for better performance.
110 template<>
PutN(GenericStringBuffer<UTF8<>> & stream,char c,size_t n)111 inline void PutN(GenericStringBuffer<UTF8<> >& stream, char c, size_t n) {
112     std::memset(stream.stack_.Push<char>(n), c, n * sizeof(c));
113 }
114 
115 RAPIDJSON_NAMESPACE_END
116 
117 #if defined(__clang__)
118 RAPIDJSON_DIAG_POP
119 #endif
120 
121 #endif // RAPIDJSON_STRINGBUFFER_H_
122