43 lines
959 B
C++
43 lines
959 B
C++
// SPDX-License-Identifier: BSD-2-Clause
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// author: Max Kellermann <max.kellermann@gmail.com>
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#pragma once
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#include <cstddef>
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#include <span>
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#include <type_traits>
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/**
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* An interface that can read bytes from a stream until the stream
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* ends.
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*
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* This interface is simpler and less cumbersome to use than
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* #InputStream.
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*/
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class Reader {
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public:
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Reader() = default;
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Reader(const Reader &) = delete;
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/**
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* Read data from the stream.
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*
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* @return the number of bytes read into the given buffer or 0
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* on end-of-stream
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*/
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[[nodiscard]]
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virtual std::size_t Read(std::span<std::byte> dest) = 0;
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/**
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* Like Read(), but throws an exception when there is not
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* enough data to fill the destination buffer.
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*/
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void ReadFull(std::span<std::byte> dest);
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template<typename T>
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requires std::is_standard_layout_v<T> && std::is_trivially_copyable_v<T>
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void ReadT(T &dest) {
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ReadFull(std::as_writable_bytes(std::span{&dest, 1}));
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}
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};
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