mirror of
https://github.com/aykhans/AzSuicideDataVisualization.git
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168 lines
5.7 KiB
C++
168 lines
5.7 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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// Buffered stream implementations
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#pragma once
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#include <cstdint>
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#include <memory>
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#include "arrow/io/concurrency.h"
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#include "arrow/io/interfaces.h"
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#include "arrow/util/string_view.h"
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#include "arrow/util/visibility.h"
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namespace arrow {
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class Buffer;
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class MemoryPool;
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class Status;
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namespace io {
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class ARROW_EXPORT BufferedOutputStream : public OutputStream {
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public:
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~BufferedOutputStream() override;
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/// \brief Create a buffered output stream wrapping the given output stream.
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/// \param[in] buffer_size the size of the temporary write buffer
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/// \param[in] pool a MemoryPool to use for allocations
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/// \param[in] raw another OutputStream
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/// \return the created BufferedOutputStream
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static Result<std::shared_ptr<BufferedOutputStream>> Create(
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int64_t buffer_size, MemoryPool* pool, std::shared_ptr<OutputStream> raw);
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/// \brief Resize internal buffer
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/// \param[in] new_buffer_size the new buffer size
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/// \return Status
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Status SetBufferSize(int64_t new_buffer_size);
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/// \brief Return the current size of the internal buffer
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int64_t buffer_size() const;
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/// \brief Return the number of remaining bytes that have not been flushed to
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/// the raw OutputStream
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int64_t bytes_buffered() const;
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/// \brief Flush any buffered writes and release the raw
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/// OutputStream. Further operations on this object are invalid
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/// \return the underlying OutputStream
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Result<std::shared_ptr<OutputStream>> Detach();
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// OutputStream interface
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/// \brief Close the buffered output stream. This implicitly closes the
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/// underlying raw output stream.
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Status Close() override;
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Status Abort() override;
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bool closed() const override;
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Result<int64_t> Tell() const override;
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// Write bytes to the stream. Thread-safe
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Status Write(const void* data, int64_t nbytes) override;
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Status Write(const std::shared_ptr<Buffer>& data) override;
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Status Flush() override;
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/// \brief Return the underlying raw output stream.
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std::shared_ptr<OutputStream> raw() const;
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private:
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explicit BufferedOutputStream(std::shared_ptr<OutputStream> raw, MemoryPool* pool);
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class ARROW_NO_EXPORT Impl;
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std::unique_ptr<Impl> impl_;
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};
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/// \class BufferedInputStream
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/// \brief An InputStream that performs buffered reads from an unbuffered
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/// InputStream, which can mitigate the overhead of many small reads in some
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/// cases
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class ARROW_EXPORT BufferedInputStream
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: public internal::InputStreamConcurrencyWrapper<BufferedInputStream> {
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public:
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~BufferedInputStream() override;
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/// \brief Create a BufferedInputStream from a raw InputStream
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/// \param[in] buffer_size the size of the temporary read buffer
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/// \param[in] pool a MemoryPool to use for allocations
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/// \param[in] raw a raw InputStream
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/// \param[in] raw_read_bound a bound on the maximum number of bytes
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/// to read from the raw input stream. The default -1 indicates that
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/// it is unbounded
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/// \return the created BufferedInputStream
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static Result<std::shared_ptr<BufferedInputStream>> Create(
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int64_t buffer_size, MemoryPool* pool, std::shared_ptr<InputStream> raw,
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int64_t raw_read_bound = -1);
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/// \brief Resize internal read buffer; calls to Read(...) will read at least
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/// \param[in] new_buffer_size the new read buffer size
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/// \return Status
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Status SetBufferSize(int64_t new_buffer_size);
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/// \brief Return the number of remaining bytes in the read buffer
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int64_t bytes_buffered() const;
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/// \brief Return the current size of the internal buffer
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int64_t buffer_size() const;
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/// \brief Release the raw InputStream. Any data buffered will be
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/// discarded. Further operations on this object are invalid
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/// \return raw the underlying InputStream
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std::shared_ptr<InputStream> Detach();
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/// \brief Return the unbuffered InputStream
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std::shared_ptr<InputStream> raw() const;
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// InputStream APIs
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bool closed() const override;
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Result<std::shared_ptr<const KeyValueMetadata>> ReadMetadata() override;
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Future<std::shared_ptr<const KeyValueMetadata>> ReadMetadataAsync(
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const IOContext& io_context) override;
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private:
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friend InputStreamConcurrencyWrapper<BufferedInputStream>;
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explicit BufferedInputStream(std::shared_ptr<InputStream> raw, MemoryPool* pool,
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int64_t raw_total_bytes_bound);
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Status DoClose();
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Status DoAbort() override;
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/// \brief Returns the position of the buffered stream, though the position
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/// of the unbuffered stream may be further advanced.
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Result<int64_t> DoTell() const;
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Result<int64_t> DoRead(int64_t nbytes, void* out);
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/// \brief Read into buffer.
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Result<std::shared_ptr<Buffer>> DoRead(int64_t nbytes);
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/// \brief Return a zero-copy string view referencing buffered data,
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/// but do not advance the position of the stream. Buffers data and
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/// expands the buffer size if necessary
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Result<util::string_view> DoPeek(int64_t nbytes) override;
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class ARROW_NO_EXPORT Impl;
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std::unique_ptr<Impl> impl_;
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};
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} // namespace io
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} // namespace arrow
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