1 // Tencent is pleased to support the open source community by making RapidJSON available. 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 MemoryStreamMemoryStream43 MemoryStream(const Ch *src, size_t size) : src_(src), begin_(src), end_(src + size), size_(size) {} 44 PeekMemoryStream45 Ch Peek() const { return RAPIDJSON_UNLIKELY(src_ == end_) ? '\0' : *src_; } TakeMemoryStream46 Ch Take() { return RAPIDJSON_UNLIKELY(src_ == end_) ? '\0' : *src_++; } TellMemoryStream47 size_t Tell() const { return static_cast<size_t>(src_ - begin_); } 48 PutBeginMemoryStream49 Ch* PutBegin() { RAPIDJSON_ASSERT(false); return 0; } PutMemoryStream50 void Put(Ch) { RAPIDJSON_ASSERT(false); } FlushMemoryStream51 void Flush() { RAPIDJSON_ASSERT(false); } PutEndMemoryStream52 size_t PutEnd(Ch*) { RAPIDJSON_ASSERT(false); return 0; } 53 54 // For encoding detection only. Peek4MemoryStream55 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_ 72
