istreamwrapper.h
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14 
15 #ifndef RAPIDJSON_ISTREAMWRAPPER_H_
16 #define RAPIDJSON_ISTREAMWRAPPER_H_
17 
18 #include "stream.h"
19 #include <iosfwd>
20 #include <ios>
21 
22 #ifdef __clang__
23 RAPIDJSON_DIAG_PUSH
24 RAPIDJSON_DIAG_OFF(padded)
25 #elif defined(_MSC_VER)
26 RAPIDJSON_DIAG_PUSH
27 RAPIDJSON_DIAG_OFF(4351) // new behavior: elements of array 'array' will be default initialized
28 #endif
29 
30 RAPIDJSON_NAMESPACE_BEGIN
31 
32 //! Wrapper of \c std::basic_istream into RapidJSON's Stream concept.
33 /*!
34  The classes can be wrapped including but not limited to:
35 
36  - \c std::istringstream
37  - \c std::stringstream
38  - \c std::wistringstream
39  - \c std::wstringstream
40  - \c std::ifstream
41  - \c std::fstream
42  - \c std::wifstream
43  - \c std::wfstream
44 
45  \tparam StreamType Class derived from \c std::basic_istream.
46 */
47 
48 template <typename StreamType>
50 public:
51  typedef typename StreamType::char_type Ch;
52 
53  //! Constructor.
54  /*!
55  \param stream stream opened for read.
56  */
57  BasicIStreamWrapper(StreamType &stream) : stream_(stream), buffer_(peekBuffer_), bufferSize_(4), bufferLast_(0), current_(buffer_), readCount_(0), count_(0), eof_(false) {
58  Read();
59  }
60 
61  //! Constructor.
62  /*!
63  \param stream stream opened for read.
64  \param buffer user-supplied buffer.
65  \param bufferSize size of buffer in bytes. Must >=4 bytes.
66  */
67  BasicIStreamWrapper(StreamType &stream, char* buffer, size_t bufferSize) : stream_(stream), buffer_(buffer), bufferSize_(bufferSize), bufferLast_(0), current_(buffer_), readCount_(0), count_(0), eof_(false) {
68  RAPIDJSON_ASSERT(bufferSize >= 4);
69  Read();
70  }
71 
72  Ch Peek() const { return *current_; }
73  Ch Take() { Ch c = *current_; Read(); return c; }
74  size_t Tell() const { return count_ + static_cast<size_t>(current_ - buffer_); }
75 
76  // Not implemented
77  void Put(Ch) { RAPIDJSON_ASSERT(false); }
78  void Flush() { RAPIDJSON_ASSERT(false); }
79  Ch* PutBegin() { RAPIDJSON_ASSERT(false); return 0; }
80  size_t PutEnd(Ch*) { RAPIDJSON_ASSERT(false); return 0; }
81 
82  // For encoding detection only.
83  const Ch* Peek4() const {
84  return (current_ + 4 - !eof_ <= bufferLast_) ? current_ : 0;
85  }
86 
87 private:
88  BasicIStreamWrapper();
89  BasicIStreamWrapper(const BasicIStreamWrapper&);
90  BasicIStreamWrapper& operator=(const BasicIStreamWrapper&);
91 
92  void Read() {
93  if (current_ < bufferLast_)
94  ++current_;
95  else if (!eof_) {
96  count_ += readCount_;
97  readCount_ = bufferSize_;
98  bufferLast_ = buffer_ + readCount_ - 1;
99  current_ = buffer_;
100 
101  if (!stream_.read(buffer_, static_cast<std::streamsize>(bufferSize_))) {
102  readCount_ = static_cast<size_t>(stream_.gcount());
103  *(bufferLast_ = buffer_ + readCount_) = '\0';
104  eof_ = true;
105  }
106  }
107  }
108 
109  StreamType &stream_;
110  Ch peekBuffer_[4], *buffer_;
111  size_t bufferSize_;
112  Ch *bufferLast_;
113  Ch *current_;
114  size_t readCount_;
115  size_t count_; //!< Number of characters read
116  bool eof_;
117 };
118 
119 typedef BasicIStreamWrapper<std::istream> IStreamWrapper;
120 typedef BasicIStreamWrapper<std::wistream> WIStreamWrapper;
121 
122 #if defined(__clang__) || defined(_MSC_VER)
123 RAPIDJSON_DIAG_POP
124 #endif
125 
126 RAPIDJSON_NAMESPACE_END
127 
128 #endif // RAPIDJSON_ISTREAMWRAPPER_H_
rapidjson::BasicIStreamWrapper
Wrapper of std::basic_istream into RapidJSON's Stream concept.
Definition: istreamwrapper.h:49
RAPIDJSON_ASSERT
#define RAPIDJSON_ASSERT(x)
Assertion.
Definition: rapidjson.h:406
rapidjson::BasicIStreamWrapper::BasicIStreamWrapper
BasicIStreamWrapper(StreamType &stream)
Constructor.
Definition: istreamwrapper.h:57
rapidjson::BasicIStreamWrapper::BasicIStreamWrapper
BasicIStreamWrapper(StreamType &stream, char *buffer, size_t bufferSize)
Constructor.
Definition: istreamwrapper.h:67