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https://github.com/SerenityOS/serenity
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3f7d97f098
These methods are slightly more convenient than storing the Bytes separately. However, it it feels unsanitary to reach in and access this data directly. Both of the users of these already have the [Readonly]Bytes available in their constructors, and can easily avoid using these methods, so let's remove them entirely.
79 lines
2.3 KiB
C++
79 lines
2.3 KiB
C++
/*
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* Copyright (c) 2021, kleines Filmröllchen <filmroellchen@serenityos.org>.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/OwnPtr.h>
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#include <AK/Stream.h>
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#include <AK/Vector.h>
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namespace AK {
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/// A stream class that allows for reading/writing on a preallocated memory area
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/// using a single read/write head.
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class FixedMemoryStream final : public SeekableStream {
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public:
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explicit FixedMemoryStream(Bytes bytes);
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explicit FixedMemoryStream(ReadonlyBytes bytes);
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virtual bool is_eof() const override;
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virtual bool is_open() const override;
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virtual void close() override;
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virtual ErrorOr<void> truncate(size_t) override;
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virtual ErrorOr<Bytes> read_some(Bytes bytes) override;
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virtual ErrorOr<void> read_until_filled(Bytes bytes) override;
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virtual ErrorOr<size_t> seek(i64 offset, SeekMode seek_mode = SeekMode::SetPosition) override;
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virtual ErrorOr<size_t> write_some(ReadonlyBytes bytes) override;
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virtual ErrorOr<void> write_until_depleted(ReadonlyBytes bytes) override;
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size_t offset() const;
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size_t remaining() const;
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private:
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Bytes m_bytes;
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size_t m_offset { 0 };
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bool m_writing_enabled { true };
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};
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/// A stream class that allows for writing to an automatically allocating memory area
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/// and reading back the written data afterwards.
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class AllocatingMemoryStream final : public Stream {
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public:
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static constexpr size_t CHUNK_SIZE = 4096;
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virtual ErrorOr<Bytes> read_some(Bytes) override;
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virtual ErrorOr<size_t> write_some(ReadonlyBytes) override;
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virtual ErrorOr<void> discard(size_t) override;
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virtual bool is_eof() const override;
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virtual bool is_open() const override;
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virtual void close() override;
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size_t used_buffer_size() const;
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ErrorOr<Optional<size_t>> offset_of(ReadonlyBytes needle) const;
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private:
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// Note: We set the inline buffer capacity to zero to make moving chunks as efficient as possible.
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using Chunk = AK::Detail::ByteBuffer<0>;
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ErrorOr<ReadonlyBytes> next_read_range();
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ErrorOr<Bytes> next_write_range();
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void cleanup_unused_chunks();
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Vector<Chunk> m_chunks;
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size_t m_read_offset = 0;
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size_t m_write_offset = 0;
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};
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}
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#if USING_AK_GLOBALLY
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using AK::AllocatingMemoryStream;
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using AK::FixedMemoryStream;
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#endif
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