65 lines
2.2 KiB
C++
65 lines
2.2 KiB
C++
// Licensed to the Apache Software Foundation (ASF) under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership. The ASF licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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#pragma once
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#include <stdint.h>
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#include "common/status.h"
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#include "exec/file_reader.h"
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#include "olap/olap_define.h"
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namespace doris {
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// Buffered Reader
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// Add a cache layer between the caller and the file reader to reduce the
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// times of calls to the read function to speed up.
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class BufferedReader : public FileReader {
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public:
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// If the reader need the file size, set it when construct FileReader.
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// There is no other way to set the file size.
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BufferedReader(FileReader* reader, int64_t = 1024 * 1024);
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virtual ~BufferedReader();
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virtual Status open() override;
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// Read
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virtual Status read(uint8_t* buf, size_t* buf_len, bool* eof) override;
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virtual Status readat(int64_t position, int64_t nbytes, int64_t* bytes_read,
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void* out) override;
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virtual Status read_one_message(std::unique_ptr<uint8_t[]>* buf, size_t* length) override;
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virtual int64_t size() override;
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virtual Status seek(int64_t position) override;
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virtual Status tell(int64_t* position) override;
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virtual void close() override;
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virtual bool closed() override;
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private:
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Status _fill();
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Status _read_once(int64_t position, int64_t nbytes, int64_t* bytes_read, void* out);
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private:
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FileReader* _reader;
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char* _buffer;
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int64_t _buffer_size;
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int64_t _buffer_offset;
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int64_t _buffer_limit;
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int64_t _cur_offset;
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};
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} // namespace doris
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