filereadstream.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_FILEREADSTREAM_H_
#define RAPIDJSON_FILEREADSTREAM_H_

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

#ifdef __clang__
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(padded)
RAPIDJSON_DIAG_OFF(unreachable-code)
RAPIDJSON_DIAG_OFF(missing-noreturn)
#endif

RAPIDJSON_NAMESPACE_BEGIN


class FileReadStream {
public:
 typedef char Ch; 


 FileReadStream(std::FILE* fp, char* buffer, size_t bufferSize) : fp_(fp), buffer_(buffer), bufferSize_(bufferSize), bufferLast_(0), current_(buffer_), readCount_(0), count_(0), eof_(false) { 
 RAPIDJSON_ASSERT(fp_ != 0);
 RAPIDJSON_ASSERT(bufferSize >= 4);
 Read();
 }

 Ch Peek() const { return *current_; }
 Ch Take() { Ch c = *current_; Read(); return c; }
 size_t Tell() const { return count_ + static_cast<size_t>(current_ - buffer_); }

 // Not implemented
 void Put(Ch) { RAPIDJSON_ASSERT(false); }
 void Flush() { RAPIDJSON_ASSERT(false); } 
 Ch* PutBegin() { RAPIDJSON_ASSERT(false); return 0; }
 size_t PutEnd(Ch*) { RAPIDJSON_ASSERT(false); return 0; }

 // For encoding detection only.
 const Ch* Peek4() const {
 return (current_ + 4 <= bufferLast_) ? current_ : 0;
 }

private:
 void Read() {
 if (current_ < bufferLast_)
 ++current_;
 else if (!eof_) {
 count_ += readCount_;
 readCount_ = fread(buffer_, 1, bufferSize_, fp_);
 bufferLast_ = buffer_ + readCount_ - 1;
 current_ = buffer_;

 if (readCount_ < bufferSize_) {
 buffer_[readCount_] = '\0';
 ++bufferLast_;
 eof_ = true;
 }
 }
 }

 std::FILE* fp_;
 Ch *buffer_;
 size_t bufferSize_;
 Ch *bufferLast_;
 Ch *current_;
 size_t readCount_;
 size_t count_; 
 bool eof_;
};

RAPIDJSON_NAMESPACE_END

#ifdef __clang__
RAPIDJSON_DIAG_POP
#endif

#endif // RAPIDJSON_FILESTREAM_H_