stringbuffer.h

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// 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_STRINGBUFFER_H_
#define RAPIDJSON_STRINGBUFFER_H_

#include "stream.h"
#include "internal/stack.h"

#if RAPIDJSON_HAS_CXX11_RVALUE_REFS
#include <utility>  // std::move
#endif

#include "internal/stack.h"

#if defined(__clang__)
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(c++ 98 - compat)
#endif

RAPIDJSON_NAMESPACE_BEGIN


template <typename Encoding, typename Allocator = CrtAllocator>
class GenericStringBuffer
{
public:
  typedef typename Encoding::Ch Ch;

  GenericStringBuffer(Allocator* allocator = 0, size_t capacity = kDefaultCapacity) : stack_(allocator, capacity)
  {
  }

#if RAPIDJSON_HAS_CXX11_RVALUE_REFS
  GenericStringBuffer(GenericStringBuffer&& rhs) : stack_(std::move(rhs.stack_))
  {
  }
  GenericStringBuffer& operator=(GenericStringBuffer&& rhs)
  {
    if (&rhs != this)
      stack_ = std::move(rhs.stack_);
    return *this;
  }
#endif

  void Put(Ch c)
  {
    *stack_.template Push<Ch>() = c;
  }
  void PutUnsafe(Ch c)
  {
    *stack_.template PushUnsafe<Ch>() = c;
  }
  void Flush()
  {
  }

  void Clear()
  {
    stack_.Clear();
  }
  void ShrinkToFit()
  {
    // Push and pop a null terminator. This is safe.
    *stack_.template Push<Ch>() = '\0';
    stack_.ShrinkToFit();
    stack_.template Pop<Ch>(1);
  }

  void Reserve(size_t count)
  {
    stack_.template Reserve<Ch>(count);
  }
  Ch* Push(size_t count)
  {
    return stack_.template Push<Ch>(count);
  }
  Ch* PushUnsafe(size_t count)
  {
    return stack_.template PushUnsafe<Ch>(count);
  }
  void Pop(size_t count)
  {
    stack_.template Pop<Ch>(count);
  }

  const Ch* GetString() const
  {
    // Push and pop a null terminator. This is safe.
    *stack_.template Push<Ch>() = '\0';
    stack_.template Pop<Ch>(1);

    return stack_.template Bottom<Ch>();
  }

  size_t GetSize() const
  {
    return stack_.GetSize();
  }

  size_t GetLength() const
  {
    return stack_.GetSize() / sizeof(Ch);
  }

  static const size_t kDefaultCapacity = 256;
  mutable internal::Stack<Allocator> stack_;

private:
  // Prohibit copy constructor & assignment operator.
  GenericStringBuffer(const GenericStringBuffer&);
  GenericStringBuffer& operator=(const GenericStringBuffer&);
};

typedef GenericStringBuffer<UTF8<> > StringBuffer;

template <typename Encoding, typename Allocator>
inline void PutReserve(GenericStringBuffer<Encoding, Allocator>& stream, size_t count)
{
  stream.Reserve(count);
}

template <typename Encoding, typename Allocator>
inline void PutUnsafe(GenericStringBuffer<Encoding, Allocator>& stream, typename Encoding::Ch c)
{
  stream.PutUnsafe(c);
}

template <>
inline void PutN(GenericStringBuffer<UTF8<> >& stream, char c, size_t n)
{
  std::memset(stream.stack_.Push<char>(n), c, n * sizeof(c));
}

RAPIDJSON_NAMESPACE_END

#if defined(__clang__)
RAPIDJSON_DIAG_POP
#endif

#endif  // RAPIDJSON_STRINGBUFFER_H_