text: // Tencent is pleased to support the open source community by making RapidJSON available.
  //
  // Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
  //
  // Licensed under the MIT License (the "License"); you may not use this file except
  // in compliance with the License. You may obtain a copy of the License at
  //
  // http://opensource.org/licenses/MIT
  //
  // Unless required by applicable law or agreed to in writing, software distributed
  // under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
  // CONDITIONS OF ANY KIND, either express or implied. See the License for the
  // specific language governing permissions and limitations under the License.
  
  #ifndef RAPIDJSON_MEMORYBUFFER_H_
  #define RAPIDJSON_MEMORYBUFFER_H_
  
  #include "stream.h"
  #include "internal/stack.h"
  
  RAPIDJSON_NAMESPACE_BEGIN
  
  //! Represents an in-memory output byte stream.
  /*!
      This class is mainly for being wrapped by EncodedOutputStream or AutoUTFOutputStream.
  
      It is similar to FileWriteBuffer but the destination is an in-memory buffer instead of a file.
  
      Differences between MemoryBuffer and StringBuffer:
      1. StringBuffer has Encoding but MemoryBuffer is only a byte buffer.
      2. StringBuffer::GetString() returns a null-terminated string. MemoryBuffer::GetBuffer() returns a buffer without terminator.
  
      \tparam Allocator type for allocating memory buffer.
      \note implements Stream concept
  */
  template <typename Allocator = CrtAllocator>
  struct GenericMemoryBuffer {
      typedef char Ch; // byte
  
      GenericMemoryBuffer(Allocator* allocator = 0, size_t capacity = kDefaultCapacity) : stack_(allocator, capacity) {}
  
      void Put(Ch c) {
          *stack_.template Push<Ch>() = c;
      }
      void Flush() {}
  
      void Clear() {
          stack_.Clear();
      }
      void ShrinkToFit() {
          stack_.ShrinkToFit();
      }
      Ch* Push(size_t count) {
          return stack_.template Push<Ch>(count);
      }
      void Pop(size_t count) {
          stack_.template Pop<Ch>(count);
      }
  
      const Ch* GetBuffer() const {
          return stack_.template Bottom<Ch>();
      }
  
      size_t GetSize() const {
          return stack_.GetSize();
      }
  
      static const size_t kDefaultCapacity = 256;
      mutable internal::Stack<Allocator> stack_;
  };
  
  typedef GenericMemoryBuffer<> MemoryBuffer;
  
  //! Implement specialized version of PutN() with memset() for better performance.
  template<>
  inline void PutN(MemoryBuffer& memoryBuffer, char c, size_t n) {
      std::memset(memoryBuffer.stack_.Push<char>(n), c, n * sizeof(c));
  }
  
  RAPIDJSON_NAMESPACE_END
  
  #endif // RAPIDJSON_MEMORYBUFFER_H_
  