RapidJSON: include/rapidjson/memorystream.h Source File

memorystream.h
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2 //
3 // Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip.
4 //
5 // Licensed under the MIT License (the "License"); you may not use this file except
6 // in compliance with the License. You may obtain a copy of the License at
7 //
8 // http://opensource.org/licenses/MIT
9 //
10 // Unless required by applicable law or agreed to in writing, software distributed
11 // under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
12 // CONDITIONS OF ANY KIND, either express or implied. See the License for the
13 // specific language governing permissions and limitations under the License.
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