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. All rights reserved. 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 "rapidjson.h" 19 20 RAPIDJSON_NAMESPACE_BEGIN 21 22 //! Represents an in-memory input byte stream. 23 /*! 24 This class is mainly for being wrapped by EncodedInputStream or AutoUTFInputStream. 25 26 It is similar to FileReadBuffer but the source is an in-memory buffer instead of a file. 27 28 Differences between MemoryStream and StringStream: 29 1. StringStream has encoding but MemoryStream is a byte stream. 30 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. 31 3. MemoryStream supports Peek4() for encoding detection. StringStream is specified with an encoding so it should not have Peek4(). 32 \note implements Stream concept 33 */ 34 struct MemoryStream { 35 typedef char Ch; // byte 36 37 MemoryStream(const Ch *src, size_t size) : src_(src), begin_(src), end_(src + size), size_(size) {} 38 39 Ch Peek() const { return (src_ == end_) ? '\0' : *src_; } 40 Ch Take() { return (src_ == end_) ? '\0' : *src_++; } 41 size_t Tell() const { return static_cast<size_t>(src_ - begin_); } 42 43 Ch* PutBegin() { RAPIDJSON_ASSERT(false); return 0; } 44 void Put(Ch) { RAPIDJSON_ASSERT(false); } 45 void Flush() { RAPIDJSON_ASSERT(false); } 46 size_t PutEnd(Ch*) { RAPIDJSON_ASSERT(false); return 0; } 47 48 // For encoding detection only. 49 const Ch* Peek4() const { 50 return Tell() + 4 <= size_ ? src_ : 0; 51 } 52 53 const Ch* src_; //!< Current read position. 54 const Ch* begin_; //!< Original head of the string. 55 const Ch* end_; //!< End of stream. 56 size_t size_; //!< Size of the stream. 57 }; 58 59 RAPIDJSON_NAMESPACE_END 60 61 #endif // RAPIDJSON_MEMORYBUFFER_H_ 62
