filereadstream.h

Engine/source/persistence/rapidjson/filereadstream.h

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Detailed Description

  1
  2// Tencent is pleased to support the open source community by making RapidJSON available.
  3// 
  4// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
  5//
  6// Licensed under the MIT License (the "License"); you may not use this file except
  7// in compliance with the License. You may obtain a copy of the License at
  8//
  9// http://opensource.org/licenses/MIT
 10//
 11// Unless required by applicable law or agreed to in writing, software distributed 
 12// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR 
 13// CONDITIONS OF ANY KIND, either express or implied. See the License for the 
 14// specific language governing permissions and limitations under the License.
 15
 16#ifndef RAPIDJSON_FILEREADSTREAM_H_
 17#define RAPIDJSON_FILEREADSTREAM_H_
 18
 19#include "stream.h"
 20#include <cstdio>
 21
 22#ifdef __clang__
 23RAPIDJSON_DIAG_PUSH
 24RAPIDJSON_DIAG_OFF(padded)
 25RAPIDJSON_DIAG_OFF(unreachable-code)
 26RAPIDJSON_DIAG_OFF(missing-noreturn)
 27#endif
 28
 29RAPIDJSON_NAMESPACE_BEGIN
 30
 31//! File byte stream for input using fread().
 32/*!
 33    \note implements Stream concept
 34*/
 35class FileReadStream {
 36public:
 37    typedef char Ch;    //!< Character type (byte).
 38
 39    //! Constructor.
 40    /*!
 41        \param fp File pointer opened for read.
 42        \param buffer user-supplied buffer.
 43        \param bufferSize size of buffer in bytes. Must >=4 bytes.
 44    */
 45    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) { 
 46        RAPIDJSON_ASSERT(fp_ != 0);
 47        RAPIDJSON_ASSERT(bufferSize >= 4);
 48        Read();
 49    }
 50
 51    Ch Peek() const { return *current_; }
 52    Ch Take() { Ch c = *current_; Read(); return c; }
 53    size_t Tell() const { return count_ + static_cast<size_t>(current_ - buffer_); }
 54
 55    // Not implemented
 56    void Put(Ch) { RAPIDJSON_ASSERT(false); }
 57    void Flush() { RAPIDJSON_ASSERT(false); } 
 58    Ch* PutBegin() { RAPIDJSON_ASSERT(false); return 0; }
 59    size_t PutEnd(Ch*) { RAPIDJSON_ASSERT(false); return 0; }
 60
 61    // For encoding detection only.
 62    const Ch* Peek4() const {
 63        return (current_ + 4 - !eof_ <= bufferLast_) ? current_ : 0;
 64    }
 65
 66private:
 67    void Read() {
 68        if (current_ < bufferLast_)
 69            ++current_;
 70        else if (!eof_) {
 71            count_ += readCount_;
 72            readCount_ = std::fread(buffer_, 1, bufferSize_, fp_);
 73            bufferLast_ = buffer_ + readCount_ - 1;
 74            current_ = buffer_;
 75
 76            if (readCount_ < bufferSize_) {
 77                buffer_[readCount_] = '\0';
 78                ++bufferLast_;
 79                eof_ = true;
 80            }
 81        }
 82    }
 83
 84    std::FILE* fp_;
 85    Ch *buffer_;
 86    size_t bufferSize_;
 87    Ch *bufferLast_;
 88    Ch *current_;
 89    size_t readCount_;
 90    size_t count_;  //!< Number of characters read
 91    bool eof_;
 92};
 93
 94RAPIDJSON_NAMESPACE_END
 95
 96#ifdef __clang__
 97RAPIDJSON_DIAG_POP
 98#endif
 99
100#endif // RAPIDJSON_FILESTREAM_H_
101