// 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_FILEWRITESTREAM_H_
#define RAPIDJSON_FILEWRITESTREAM_H_

#include "stream.h"
#include <cstdio>

#ifdef __clang__
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(unreachable - code)
#endif

RAPIDJSON_NAMESPACE_BEGIN

//! Wrapper of C file stream for output using fwrite().
/*!
    \note implements Stream concept
*/
class FileWriteStream
{
    public:
    typedef char Ch; //!< Character type. Only support char.

    FileWriteStream(std::FILE* fp, char* buffer, size_t bufferSize)
        : fp_(fp), buffer_(buffer), bufferEnd_(buffer + bufferSize), current_(buffer_)
    {
        RAPIDJSON_ASSERT(fp_ != 0);
    }

    void Put(char c)
    {
        if(current_ >= bufferEnd_)
            Flush();

        *current_++ = c;
    }

    void PutN(char c, size_t n)
    {
        size_t avail = static_cast<size_t>(bufferEnd_ - current_);
        while(n > avail)
        {
            std::memset(current_, c, avail);
            current_ += avail;
            Flush();
            n -= avail;
            avail = static_cast<size_t>(bufferEnd_ - current_);
        }

        if(n > 0)
        {
            std::memset(current_, c, n);
            current_ += n;
        }
    }

    void Flush()
    {
        if(current_ != buffer_)
        {
            size_t result = std::fwrite(buffer_, 1, static_cast<size_t>(current_ - buffer_), fp_);
            if(result < static_cast<size_t>(current_ - buffer_))
            {
                // failure deliberately ignored at this time
                // added to avoid warn_unused_result build errors
            }
            current_ = buffer_;
        }
    }

    // Not implemented
    char Peek() const
    {
        RAPIDJSON_ASSERT(false);
        return 0;
    }
    char Take()
    {
        RAPIDJSON_ASSERT(false);
        return 0;
    }
    size_t Tell() const
    {
        RAPIDJSON_ASSERT(false);
        return 0;
    }
    char* PutBegin()
    {
        RAPIDJSON_ASSERT(false);
        return 0;
    }
    size_t PutEnd(char*)
    {
        RAPIDJSON_ASSERT(false);
        return 0;
    }

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

    std::FILE* fp_;
    char* buffer_;
    char* bufferEnd_;
    char* current_;
};

//! Implement specialized version of PutN() with memset() for better performance.
template <>
inline void PutN(FileWriteStream& stream, char c, size_t n)
{
    stream.PutN(c, n);
}

RAPIDJSON_NAMESPACE_END

#ifdef __clang__
RAPIDJSON_DIAG_POP
#endif

#endif // RAPIDJSON_FILESTREAM_H_
