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istreamwrapper.h
// 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>
#ifdef __clang__
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(padded)
#endif
#ifdef _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;
BasicIStreamWrapper(StreamType& stream) : stream_(stream), count_(), peekBuffer_() {}
Ch Peek() const {
typename StreamType::int_type c = stream_.peek();
return RAPIDJSON_LIKELY(c != StreamType::traits_type::eof()) ? static_cast<Ch>(c) : '\0';
}
Ch Take() {
typename StreamType::int_type c = stream_.get();
if (RAPIDJSON_LIKELY(c != StreamType::traits_type::eof())) {
count_++;
return static_cast<Ch>(c);
}
else
return '\0';
}
// tellg() may return -1 when failed. So we count by ourself.
size_t Tell() const { return count_; }
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; }
// For encoding detection only.
const Ch* Peek4() const {
RAPIDJSON_ASSERT(sizeof(Ch) == 1); // Only usable for byte stream.
int i;
bool hasError = false;
for (i = 0; i < 4; ++i) {
typename StreamType::int_type c = stream_.get();
if (c == StreamType::traits_type::eof()) {
hasError = true;
stream_.clear();
break;
}
peekBuffer_[i] = static_cast<Ch>(c);
}
for (--i; i >= 0; --i)
stream_.putback(peekBuffer_[i]);
return !hasError ? peekBuffer_ : 0;
}
private:
BasicIStreamWrapper(const BasicIStreamWrapper&);
BasicIStreamWrapper& operator=(const BasicIStreamWrapper&);
StreamType& stream_;
size_t count_; //!< Number of characters read. Note:
mutable Ch peekBuffer_[4];
};
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_
rapidjson::BasicIStreamWrapper
Wrapper of std::basic_istream into RapidJSON's Stream concept.
Definition istreamwrapper.h:50
rapidjson::GenericMemberIterator
(Constant) member iterator for a JSON object value
Definition document.h:104
RAPIDJSON_LIKELY
#define RAPIDJSON_LIKELY(x)
Compiler branching hint for expression with high probability to be true.
Definition rapidjson.h:455
RAPIDJSON_ASSERT
#define RAPIDJSON_ASSERT(x)
Assertion.
Definition rapidjson.h:402