// Tencent is pleased to support the open source community by making RapidJSON available. // // Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved. // // Licensed under the MIT License (the "License"); you may not use this file except // in compliance with the License. You may obtain a copy of the License at // // http://opensource.org/licenses/MIT // // Unless required by applicable law or agreed to in writing, software distributed // under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR // CONDITIONS OF ANY KIND, either express or implied. See the License for the // specific language governing permissions and limitations under the License. #include "rapidjson.h" #ifndef RAPIDJSON_STREAM_H_ #define RAPIDJSON_STREAM_H_ #include "encodings.h" RAPIDJSON_NAMESPACE_BEGIN /////////////////////////////////////////////////////////////////////////////// // Stream /*! \class rapidjson::Stream \brief Concept for reading and writing characters. For read-only stream, no need to implement PutBegin(), Put(), Flush() and PutEnd(). For write-only stream, only need to implement Put() and Flush(). \code concept Stream { typename Ch; //!< Character type of the stream. //! Read the current character from stream without moving the read cursor. Ch Peek() const; //! Read the current character from stream and moving the read cursor to next character. Ch Take(); //! Get the current read cursor. //! \return Number of characters read from start. size_t Tell(); //! Begin writing operation at the current read pointer. //! \return The begin writer pointer. Ch* PutBegin(); //! Write a character. void Put(Ch c); //! Flush the buffer. void Flush(); //! End the writing operation. //! \param begin The begin write pointer returned by PutBegin(). //! \return Number of characters written. size_t PutEnd(Ch* begin); } \endcode */ //! Provides additional information for stream. /*! By using traits pattern, this type provides a default configuration for stream. For custom stream, this type can be specialized for other configuration. See TEST(Reader, CustomStringStream) in readertest.cpp for example. */ template<typename Stream> struct StreamTraits { //! Whether to make local copy of stream for optimization during parsing. /*! By default, for safety, streams do not use local copy optimization. Stream that can be copied fast should specialize this, like StreamTraits<StringStream>. */ enum { copyOptimization = 0 }; }; //! Reserve n characters for writing to a stream. template<typename Stream> inline void PutReserve(Stream& stream, size_t count) { (void)stream; (void)count; } //! Write character to a stream, presuming buffer is reserved. template<typename Stream> inline void PutUnsafe(Stream& stream, typename Stream::Ch c) { stream.Put(c); } //! Put N copies of a character to a stream. template<typename Stream, typename Ch> inline void PutN(Stream& stream, Ch c, size_t n) { PutReserve(stream, n); for (size_t i = 0; i < n; i++) PutUnsafe(stream, c); } /////////////////////////////////////////////////////////////////////////////// // StringStream //! Read-only string stream. /*! \note implements Stream concept */ template <typename Encoding> struct GenericStringStream { typedef typename Encoding::Ch Ch; GenericStringStream(const Ch *src) : src_(src), head_(src) {} Ch Peek() const { return *src_; } Ch Take() { return *src_++; } size_t Tell() const { return static_cast<size_t>(src_ - head_); } Ch* PutBegin() { RAPIDJSON_ASSERT(false); return 0; } void Put(Ch) { RAPIDJSON_ASSERT(false); } void Flush() { RAPIDJSON_ASSERT(false); } size_t PutEnd(Ch*) { RAPIDJSON_ASSERT(false); return 0; } const Ch* src_; //!< Current read position. const Ch* head_; //!< Original head of the string. }; template <typename Encoding> struct StreamTraits<GenericStringStream<Encoding> > { enum { copyOptimization = 1 }; }; //! String stream with UTF8 encoding. typedef GenericStringStream<UTF8<> > StringStream; /////////////////////////////////////////////////////////////////////////////// // InsituStringStream //! A read-write string stream. /*! This string stream is particularly designed for in-situ parsing. \note implements Stream concept */ template <typename Encoding> struct GenericInsituStringStream { typedef typename Encoding::Ch Ch; GenericInsituStringStream(Ch *src) : src_(src), dst_(0), head_(src) {} // Read Ch Peek() { return *src_; } Ch Take() { return *src_++; } size_t Tell() { return static_cast<size_t>(src_ - head_); } // Write void Put(Ch c) { RAPIDJSON_ASSERT(dst_ != 0); *dst_++ = c; } Ch* PutBegin() { return dst_ = src_; } size_t PutEnd(Ch* begin) { return static_cast<size_t>(dst_ - begin); } void Flush() {} Ch* Push(size_t count) { Ch* begin = dst_; dst_ += count; return begin; } void Pop(size_t count) { dst_ -= count; } Ch* src_; Ch* dst_; Ch* head_; }; template <typename Encoding> struct StreamTraits<GenericInsituStringStream<Encoding> > { enum { copyOptimization = 1 }; }; //! Insitu string stream with UTF8 encoding. typedef GenericInsituStringStream<UTF8<> > InsituStringStream; RAPIDJSON_NAMESPACE_END #endif // RAPIDJSON_STREAM_H_