100 lines
2.9 KiB
C++
100 lines
2.9 KiB
C++
// Tencent is pleased to support the open source community by making RapidJSON available.
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//
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// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip.
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//
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// Licensed under the MIT License (the "License"); you may not use this file except
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// in compliance with the License. You may obtain a copy of the License at
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//
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// http://opensource.org/licenses/MIT
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//
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// Unless required by applicable law or agreed to in writing, software distributed
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// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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// CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations under the License.
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#ifndef RAPIDJSON_FILEREADSTREAM_H_
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#define RAPIDJSON_FILEREADSTREAM_H_
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#include "stream.h"
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#include <cstdio>
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#ifdef __clang__
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RAPIDJSON_DIAG_PUSH
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RAPIDJSON_DIAG_OFF(padded)
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RAPIDJSON_DIAG_OFF(unreachable-code)
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RAPIDJSON_DIAG_OFF(missing-noreturn)
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#endif
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RAPIDJSON_NAMESPACE_BEGIN
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//! File byte stream for input using fread().
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/*!
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\note implements Stream concept
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*/
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class FileReadStream {
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public:
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typedef char Ch; //!< Character type (byte).
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//! Constructor.
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/*!
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\param fp File pointer opened for read.
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\param buffer user-supplied buffer.
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\param bufferSize size of buffer in bytes. Must >=4 bytes.
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*/
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FileReadStream(std::FILE* fp, char* buffer, size_t bufferSize) : fp_(fp), buffer_(buffer), bufferSize_(bufferSize), bufferLast_(0), current_(buffer_), readCount_(0), count_(0), eof_(false) {
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RAPIDJSON_ASSERT(fp_ != 0);
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RAPIDJSON_ASSERT(bufferSize >= 4);
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Read();
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}
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Ch Peek() const { return *current_; }
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Ch Take() { Ch c = *current_; Read(); return c; }
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size_t Tell() const { return count_ + static_cast<size_t>(current_ - buffer_); }
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// Not implemented
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void Put(Ch) { RAPIDJSON_ASSERT(false); }
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void Flush() { RAPIDJSON_ASSERT(false); }
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Ch* PutBegin() { RAPIDJSON_ASSERT(false); return 0; }
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size_t PutEnd(Ch*) { RAPIDJSON_ASSERT(false); return 0; }
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// For encoding detection only.
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const Ch* Peek4() const {
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return (current_ + 4 - !eof_ <= bufferLast_) ? current_ : 0;
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}
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private:
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void Read() {
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if (current_ < bufferLast_)
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++current_;
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else if (!eof_) {
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count_ += readCount_;
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readCount_ = std::fread(buffer_, 1, bufferSize_, fp_);
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bufferLast_ = buffer_ + readCount_ - 1;
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current_ = buffer_;
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if (readCount_ < bufferSize_) {
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buffer_[readCount_] = '\0';
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++bufferLast_;
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eof_ = true;
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}
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}
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}
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std::FILE* fp_;
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Ch *buffer_;
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size_t bufferSize_;
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Ch *bufferLast_;
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Ch *current_;
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size_t readCount_;
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size_t count_; //!< Number of characters read
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bool eof_;
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};
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RAPIDJSON_NAMESPACE_END
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#ifdef __clang__
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RAPIDJSON_DIAG_POP
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#endif
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#endif // RAPIDJSON_FILESTREAM_H_
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