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 "rapidjson.h"
19 
20 #if RAPIDJSON_HAS_CXX11_RVALUE_REFS
21 #include <utility> // std::move
22 #endif
23 
24 #include "internal/stack.h"
25 
26 RAPIDJSON_NAMESPACE_BEGIN
27 
28 //! Represents an in-memory output stream.
29 /*!
30     \tparam Encoding Encoding of the stream.
31     \tparam Allocator type for allocating memory buffer.
32     \note implements Stream concept
33 */
34 template <typename Encoding, typename Allocator = CrtAllocator>
35 class GenericStringBuffer {
36 public:
37     typedef typename Encoding::Ch Ch;
38 
stack_(allocator,capacity)39     GenericStringBuffer(Allocator* allocator = 0, size_t capacity = kDefaultCapacity) : stack_(allocator, capacity) {}
40 
41 #if RAPIDJSON_HAS_CXX11_RVALUE_REFS
GenericStringBuffer(GenericStringBuffer && rhs)42     GenericStringBuffer(GenericStringBuffer&& rhs) : stack_(std::move(rhs.stack_)) {}
43     GenericStringBuffer& operator=(GenericStringBuffer&& rhs) {
44         if (&rhs != this)
45             stack_ = std::move(rhs.stack_);
46         return *this;
47     }
48 #endif
49 
Put(Ch c)50     void Put(Ch c) { *stack_.template Push<Ch>() = c; }
Flush()51     void Flush() {}
52 
Clear()53     void Clear() { stack_.Clear(); }
ShrinkToFit()54     void ShrinkToFit() {
55         // Push and pop a null terminator. This is safe.
56         *stack_.template Push<Ch>() = '\0';
57         stack_.ShrinkToFit();
58         stack_.template Pop<Ch>(1);
59     }
Push(size_t count)60     Ch* Push(size_t count) { return stack_.template Push<Ch>(count); }
Pop(size_t count)61     void Pop(size_t count) { stack_.template Pop<Ch>(count); }
62 
GetString()63     const Ch* GetString() const {
64         // Push and pop a null terminator. This is safe.
65         *stack_.template Push<Ch>() = '\0';
66         stack_.template Pop<Ch>(1);
67 
68         return stack_.template Bottom<Ch>();
69     }
70 
GetSize()71     size_t GetSize() const { return stack_.GetSize(); }
72 
73     static const size_t kDefaultCapacity = 256;
74     mutable internal::Stack<Allocator> stack_;
75 
76 private:
77     // Prohibit copy constructor & assignment operator.
78     GenericStringBuffer(const GenericStringBuffer&);
79     GenericStringBuffer& operator=(const GenericStringBuffer&);
80 };
81 
82 //! String buffer with UTF8 encoding
83 typedef GenericStringBuffer<UTF8<> > StringBuffer;
84 
85 //! Implement specialized version of PutN() with memset() for better performance.
86 template<>
PutN(GenericStringBuffer<UTF8<>> & stream,char c,size_t n)87 inline void PutN(GenericStringBuffer<UTF8<> >& stream, char c, size_t n) {
88     std::memset(stream.stack_.Push<char>(n), c, n * sizeof(c));
89 }
90 
91 RAPIDJSON_NAMESPACE_END
92 
93 #endif // RAPIDJSON_STRINGBUFFER_H_
94