memorystream.h
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14 
15 #ifndef RAPIDJSON_MEMORYSTREAM_H_
16 #define RAPIDJSON_MEMORYSTREAM_H_
17 
18 #include "stream.h"
19 
20 #ifdef __clang__
21 RAPIDJSON_DIAG_PUSH
22 RAPIDJSON_DIAG_OFF(unreachable-code)
23 RAPIDJSON_DIAG_OFF(missing-noreturn)
24 #endif
25 
26 RAPIDJSON_NAMESPACE_BEGIN
27 
28 //! Represents an in-memory input byte stream.
29 /*!
30  This class is mainly for being wrapped by EncodedInputStream or AutoUTFInputStream.
31 
32  It is similar to FileReadBuffer but the source is an in-memory buffer instead of a file.
33 
34  Differences between MemoryStream and StringStream:
35  1. StringStream has encoding but MemoryStream is a byte stream.
36  2. MemoryStream needs size of the source buffer and the buffer don't need to be null terminated. StringStream assume null-terminated string as source.
37  3. MemoryStream supports Peek4() for encoding detection. StringStream is specified with an encoding so it should not have Peek4().
38  \note implements Stream concept
39 */
40 struct MemoryStream {
41  typedef char Ch; // byte
42 
43  MemoryStream(const Ch *src, size_t size) : src_(src), begin_(src), end_(src + size), size_(size) {}
44 
45  Ch Peek() const { return RAPIDJSON_UNLIKELY(src_ == end_) ? '\0' : *src_; }
46  Ch Take() { return RAPIDJSON_UNLIKELY(src_ == end_) ? '\0' : *src_++; }
47  size_t Tell() const { return static_cast<size_t>(src_ - begin_); }
48 
49  Ch* PutBegin() { RAPIDJSON_ASSERT(false); return 0; }
50  void Put(Ch) { RAPIDJSON_ASSERT(false); }
51  void Flush() { RAPIDJSON_ASSERT(false); }
52  size_t PutEnd(Ch*) { RAPIDJSON_ASSERT(false); return 0; }
53 
54  // For encoding detection only.
55  const Ch* Peek4() const {
56  return Tell() + 4 <= size_ ? src_ : 0;
57  }
58 
59  const Ch* src_; //!< Current read position.
60  const Ch* begin_; //!< Original head of the string.
61  const Ch* end_; //!< End of stream.
62  size_t size_; //!< Size of the stream.
63 };
64 
65 RAPIDJSON_NAMESPACE_END
66 
67 #ifdef __clang__
68 RAPIDJSON_DIAG_POP
69 #endif
70 
71 #endif // RAPIDJSON_MEMORYBUFFER_H_
rapidjson::MemoryStream::size_
size_t size_
Size of the stream.
Definition: memorystream.h:62
rapidjson::MemoryStream
Represents an in-memory input byte stream.
Definition: memorystream.h:40
rapidjson::MemoryStream::end_
const Ch * end_
End of stream.
Definition: memorystream.h:61
RAPIDJSON_ASSERT
#define RAPIDJSON_ASSERT(x)
Assertion.
Definition: rapidjson.h:406
rapidjson::MemoryStream::begin_
const Ch * begin_
Original head of the string.
Definition: memorystream.h:60
rapidjson::MemoryStream::src_
const Ch * src_
Current read position.
Definition: memorystream.h:59
RAPIDJSON_UNLIKELY
#define RAPIDJSON_UNLIKELY(x)
Compiler branching hint for expression with low probability to be true.
Definition: rapidjson.h:476