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_MEMORYBUFFER_H_ 16 #define RAPIDJSON_MEMORYBUFFER_H_ 17 18 #include "rapidjson.h" 19 #include "internal/stack.h" 20 21 RAPIDJSON_NAMESPACE_BEGIN 22 23 //! Represents an in-memory output byte stream. 24 /*! 25 This class is mainly for being wrapped by EncodedOutputStream or AutoUTFOutputStream. 26 27 It is similar to FileWriteBuffer but the destination is an in-memory buffer instead of a file. 28 29 Differences between MemoryBuffer and StringBuffer: 30 1. StringBuffer has Encoding but MemoryBuffer is only a byte buffer. 31 2. StringBuffer::GetString() returns a null-terminated string. MemoryBuffer::GetBuffer() returns a buffer without terminator. 32 33 \tparam Allocator type for allocating memory buffer. 34 \note implements Stream concept 35 */ 36 template <typename Allocator = CrtAllocator> 37 struct GenericMemoryBuffer { 38 typedef char Ch; // byte 39 40 GenericMemoryBuffer(Allocator* allocator = 0, size_t capacity = kDefaultCapacity) : stack_(allocator, capacity) {} 41 42 void Put(Ch c) { *stack_.template Push<Ch>() = c; } 43 void Flush() {} 44 45 void Clear() { stack_.Clear(); } 46 void ShrinkToFit() { stack_.ShrinkToFit(); } 47 Ch* Push(size_t count) { return stack_.template Push<Ch>(count); } 48 void Pop(size_t count) { stack_.template Pop<Ch>(count); } 49 50 const Ch* GetBuffer() const { 51 return stack_.template Bottom<Ch>(); 52 } 53 54 size_t GetSize() const { return stack_.GetSize(); } 55 56 static const size_t kDefaultCapacity = 256; 57 mutable internal::Stack<Allocator> stack_; 58 }; 59 60 typedef GenericMemoryBuffer<> MemoryBuffer; 61 62 //! Implement specialized version of PutN() with memset() for better performance. 63 template<> 64 inline void PutN(MemoryBuffer& memoryBuffer, char c, size_t n) { 65 std::memset(memoryBuffer.stack_.Push<char>(n), c, n * sizeof(c)); 66 } 67 68 RAPIDJSON_NAMESPACE_END 69 70 #endif // RAPIDJSON_MEMORYBUFFER_H_ 71
