1 // Tencent is pleased to support the open source community by making RapidJSON available.
3 // Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
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
8 // http://opensource.org/licenses/MIT
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.
15 #ifndef RAPIDJSON_MEMORYSTREAM_H_
16 #define RAPIDJSON_MEMORYSTREAM_H_
22 RAPIDJSON_DIAG_OFF(unreachable-code)
23 RAPIDJSON_DIAG_OFF(missing-noreturn)
26 RAPIDJSON_NAMESPACE_BEGIN
28 //! Represents an in-memory input byte stream.
30 This class is mainly for being wrapped by EncodedInputStream or AutoUTFInputStream.
32 It is similar to FileReadBuffer but the source is an in-memory buffer instead of a file.
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
41 typedef char Ch; // byte
43 MemoryStream(const Ch *src, size_t size) : src_(src), begin_(src), end_(src + size), size_(size) {}
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_); }
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; }
54 // For encoding detection only.
55 const Ch* Peek4() const {
56 return Tell() + 4 <= size_ ? src_ : 0;
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.
65 RAPIDJSON_NAMESPACE_END
71 #endif // RAPIDJSON_MEMORYBUFFER_H_