filewritestream.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_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 input using fread().
/*!
\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 = 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_