Class BasicIStreamWrapper

Synopsis

#include <include/rapidjson/istreamwrapper.h>

template <typename StreamType>
class BasicIStreamWrapper

Description

Wrapper of std::basic_istream into RapidJSON's Stream concept.

The classes can be wrapped including but not limited to:

  • std::istringstream
  • std::stringstream
  • std::wistringstream
  • std::wstringstream
  • std::ifstream
  • std::fstream
  • std::wifstream
  • std::wfstream
Template Parameters

StreamType - Class derived from std::basic_istream.

Methods

BasicIStreamWrapper overloadConstructor.
Flush
Peek
Peek4
Put
PutBegin
PutEnd
Take
Tell

Source

Lines 48-117 in include/rapidjson/istreamwrapper.h.

template <typename StreamType>
class BasicIStreamWrapper {
public:
    typedef typename StreamType::char_type Ch;

    //! Constructor.
    /*!
        \param stream stream opened for read.
    */
    BasicIStreamWrapper(StreamType &stream) : stream_(stream), buffer_(peekBuffer_), bufferSize_(4), bufferLast_(0), current_(buffer_), readCount_(0), count_(0), eof_(false) { 
        Read();
    }

    //! Constructor.
    /*!
        \param stream stream opened for read.
        \param buffer user-supplied buffer.
        \param bufferSize size of buffer in bytes. Must >=4 bytes.
    */
    BasicIStreamWrapper(StreamType &stream, char* buffer, size_t bufferSize) : stream_(stream), buffer_(buffer), bufferSize_(bufferSize), bufferLast_(0), current_(buffer_), readCount_(0), count_(0), eof_(false) { 
        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 - !eof_ <= bufferLast_) ? current_ : 0;
    }

private:
    BasicIStreamWrapper();
    BasicIStreamWrapper(const BasicIStreamWrapper&);
    BasicIStreamWrapper& operator=(const BasicIStreamWrapper&);

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

            if (!stream_.read(buffer_, static_cast<std::streamsize>(bufferSize_))) {
                readCount_ = static_cast<size_t>(stream_.gcount());
                *(bufferLast_ = buffer_ + readCount_) = '\0';
                eof_ = true;
            }
        }
    }

    StreamType &stream_;
    Ch peekBuffer_[4], *buffer_;
    size_t bufferSize_;
    Ch *bufferLast_;
    Ch *current_;
    size_t readCount_;
    size_t count_;  //!< Number of characters read
    bool eof_;
};





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