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Diffstat (limited to 'include/rapidjson/istreamwrapper.h')
-rw-r--r-- | include/rapidjson/istreamwrapper.h | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/include/rapidjson/istreamwrapper.h b/include/rapidjson/istreamwrapper.h new file mode 100644 index 0000000..c4950b9 --- /dev/null +++ b/include/rapidjson/istreamwrapper.h @@ -0,0 +1,128 @@ +// 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. + +#ifndef RAPIDJSON_ISTREAMWRAPPER_H_ +#define RAPIDJSON_ISTREAMWRAPPER_H_ + +#include "stream.h" +#include <iosfwd> +#include <ios> + +#ifdef __clang__ +RAPIDJSON_DIAG_PUSH +RAPIDJSON_DIAG_OFF(padded) +#elif defined(_MSC_VER) +RAPIDJSON_DIAG_PUSH +RAPIDJSON_DIAG_OFF(4351) // new behavior: elements of array 'array' will be default initialized +#endif + +RAPIDJSON_NAMESPACE_BEGIN + +//! Wrapper of \c std::basic_istream into RapidJSON's Stream concept. +/*! + The classes can be wrapped including but not limited to: + + - \c std::istringstream + - \c std::stringstream + - \c std::wistringstream + - \c std::wstringstream + - \c std::ifstream + - \c std::fstream + - \c std::wifstream + - \c std::wfstream + + \tparam StreamType Class derived from \c std::basic_istream. +*/ + +template <typename StreamType> +class BasicIStreamWrapper { +public: + typedef typename StreamType::char_type Ch; + + //! Constructor. + /*! + \param stream stream opened for read. + */ + BasicIStreamWrapper(StreamType &stream) : stream_(stream), buffer_(peekBuffer_), bufferSize_(4), bufferLast_(0), current_(buffer_), readCount_(0), count_(0), eof_(false) { + Read(); + } + + //! Constructor. + /*! + \param stream stream opened for read. + \param buffer user-supplied buffer. + \param bufferSize size of buffer in bytes. Must >=4 bytes. + */ + BasicIStreamWrapper(StreamType &stream, char* buffer, size_t bufferSize) : stream_(stream), buffer_(buffer), bufferSize_(bufferSize), bufferLast_(0), current_(buffer_), readCount_(0), count_(0), eof_(false) { + RAPIDJSON_ASSERT(bufferSize >= 4); + Read(); + } + + Ch Peek() const { return *current_; } + Ch Take() { Ch c = *current_; Read(); return c; } + size_t Tell() const { return count_ + static_cast<size_t>(current_ - buffer_); } + + // Not implemented + void Put(Ch) { RAPIDJSON_ASSERT(false); } + void Flush() { RAPIDJSON_ASSERT(false); } + Ch* PutBegin() { RAPIDJSON_ASSERT(false); return 0; } + size_t PutEnd(Ch*) { RAPIDJSON_ASSERT(false); return 0; } + + // For encoding detection only. + const Ch* Peek4() const { + return (current_ + 4 - !eof_ <= bufferLast_) ? current_ : 0; + } + +private: + BasicIStreamWrapper(); + BasicIStreamWrapper(const BasicIStreamWrapper&); + BasicIStreamWrapper& operator=(const BasicIStreamWrapper&); + + void Read() { + if (current_ < bufferLast_) + ++current_; + else if (!eof_) { + count_ += readCount_; + readCount_ = bufferSize_; + bufferLast_ = buffer_ + readCount_ - 1; + current_ = buffer_; + + if (!stream_.read(buffer_, static_cast<std::streamsize>(bufferSize_))) { + readCount_ = static_cast<size_t>(stream_.gcount()); + *(bufferLast_ = buffer_ + readCount_) = '\0'; + eof_ = true; + } + } + } + + StreamType &stream_; + Ch peekBuffer_[4], *buffer_; + size_t bufferSize_; + Ch *bufferLast_; + Ch *current_; + size_t readCount_; + size_t count_; //!< Number of characters read + bool eof_; +}; + +typedef BasicIStreamWrapper<std::istream> IStreamWrapper; +typedef BasicIStreamWrapper<std::wistream> WIStreamWrapper; + +#if defined(__clang__) || defined(_MSC_VER) +RAPIDJSON_DIAG_POP +#endif + +RAPIDJSON_NAMESPACE_END + +#endif // RAPIDJSON_ISTREAMWRAPPER_H_ |