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Diffstat (limited to 'include/rapidjson/stream.h')
-rw-r--r-- | include/rapidjson/stream.h | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/include/rapidjson/stream.h b/include/rapidjson/stream.h new file mode 100644 index 0000000..7f2643e --- /dev/null +++ b/include/rapidjson/stream.h @@ -0,0 +1,223 @@ +// 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); +} + +/////////////////////////////////////////////////////////////////////////////// +// GenericStreamWrapper + +//! A Stream Wrapper +/*! \tThis string stream is a wrapper for any stream by just forwarding any + \treceived message to the origin stream. + \note implements Stream concept +*/ + +#if defined(_MSC_VER) && _MSC_VER <= 1800 +RAPIDJSON_DIAG_PUSH +RAPIDJSON_DIAG_OFF(4702) // unreachable code +RAPIDJSON_DIAG_OFF(4512) // assignment operator could not be generated +#endif + +template <typename InputStream, typename Encoding = UTF8<> > +class GenericStreamWrapper { +public: + typedef typename Encoding::Ch Ch; + GenericStreamWrapper(InputStream& is): is_(is) {} + + Ch Peek() const { return is_.Peek(); } + Ch Take() { return is_.Take(); } + size_t Tell() { return is_.Tell(); } + Ch* PutBegin() { return is_.PutBegin(); } + void Put(Ch ch) { is_.Put(ch); } + void Flush() { is_.Flush(); } + size_t PutEnd(Ch* ch) { return is_.PutEnd(ch); } + + // wrapper for MemoryStream + const Ch* Peek4() const { return is_.Peek4(); } + + // wrapper for AutoUTFInputStream + UTFType GetType() const { return is_.GetType(); } + bool HasBOM() const { return is_.HasBOM(); } + +protected: + InputStream& is_; +}; + +#if defined(_MSC_VER) && _MSC_VER <= 1800 +RAPIDJSON_DIAG_POP +#endif + +/////////////////////////////////////////////////////////////////////////////// +// 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_ |