// 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.

//

// 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

//! Represents an in-memory output stream.

/*!

    \tparam Encoding Encoding of the stream.

    \tparam Allocator type for allocating memory buffer.

    \note implements Stream concept

*/

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>();

    }

    //! Get the size of string in bytes in the string buffer.

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

    //! Get the length of string in Ch in the string buffer.

    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&);

};

//! String buffer with UTF8 encoding

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);

}

//! Implement specialized version of PutN() with memset() for better performance.

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_