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_FILEWRITESTREAM_H_
 16#define RAPIDJSON_FILEWRITESTREAM_H_
 17
 18#include "stream.h"
 19#include <cstdio>
 20
 21#ifdef __clang__
 22RAPIDJSON_DIAG_PUSH
 23RAPIDJSON_DIAG_OFF(unreachable-code)
 24#endif
 25
 26RAPIDJSON_NAMESPACE_BEGIN
 27
 28//! Wrapper of C file stream for input using fread().
 29/*!
 30    \note implements Stream concept
 31*/
 32class FileWriteStream {
 33public:
 34    typedef char Ch;    //!< Character type. Only support char.
 35
 36    FileWriteStream(std::FILE* fp, char* buffer, size_t bufferSize) : fp_(fp), buffer_(buffer), bufferEnd_(buffer + bufferSize), current_(buffer_) { 
 37        RAPIDJSON_ASSERT(fp_ != 0);
 38    }
 39
 40    void Put(char c) { 
 41        if (current_ >= bufferEnd_)
 42            Flush();
 43
 44        *current_++ = c;
 45    }
 46
 47    void PutN(char c, size_t n) {
 48        size_t avail = static_cast<size_t>(bufferEnd_ - current_);
 49        while (n > avail) {
 50            std::memset(current_, c, avail);
 51            current_ += avail;
 52            Flush();
 53            n -= avail;
 54            avail = static_cast<size_t>(bufferEnd_ - current_);
 55        }
 56
 57        if (n > 0) {
 58            std::memset(current_, c, n);
 59            current_ += n;
 60        }
 61    }
 62
 63    void Flush() {
 64        if (current_ != buffer_) {
 65            size_t result = fwrite(buffer_, 1, static_cast<size_t>(current_ - buffer_), fp_);
 66            if (result < static_cast<size_t>(current_ - buffer_)) {
 67                // failure deliberately ignored at this time
 68                // added to avoid warn_unused_result build errors
 69            }
 70            current_ = buffer_;
 71        }
 72    }
 73
 74    // Not implemented
 75    char Peek() const { RAPIDJSON_ASSERT(false); return 0; }
 76    char Take() { RAPIDJSON_ASSERT(false); return 0; }
 77    size_t Tell() const { RAPIDJSON_ASSERT(false); return 0; }
 78    char* PutBegin() { RAPIDJSON_ASSERT(false); return 0; }
 79    size_t PutEnd(char*) { RAPIDJSON_ASSERT(false); return 0; }
 80
 81private:
 82    // Prohibit copy constructor & assignment operator.
 83    FileWriteStream(const FileWriteStream&);
 84    FileWriteStream& operator=(const FileWriteStream&);
 85
 86    std::FILE* fp_;
 87    char *buffer_;
 88    char *bufferEnd_;
 89    char *current_;
 90};
 91
 92//! Implement specialized version of PutN() with memset() for better performance.
 93template<>
 94inline void PutN(FileWriteStream& stream, char c, size_t n) {
 95    stream.PutN(c, n);
 96}
 97
 98RAPIDJSON_NAMESPACE_END
 99
100#ifdef __clang__
101RAPIDJSON_DIAG_POP
102#endif
103
104#endif // RAPIDJSON_FILESTREAM_H_