mirror of
https://github.com/SerenityOS/serenity
synced 2024-10-04 15:09:40 +00:00
046a9faeb3
The "operation modes" of this function have very different focuses, and trying to combine both in a way where we share the most amount of code probably results in the worst performance. Instead, split up the function into "existing distances" and "no existing distances" so that we can optimize either case separately.
83 lines
2.7 KiB
C++
83 lines
2.7 KiB
C++
/*
|
|
* Copyright (c) 2022, Lucas Chollet <lucas.chollet@free.fr>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <AK/ByteBuffer.h>
|
|
#include <AK/Error.h>
|
|
#include <AK/Noncopyable.h>
|
|
#include <AK/Vector.h>
|
|
|
|
namespace AK {
|
|
|
|
class CircularBuffer {
|
|
AK_MAKE_NONCOPYABLE(CircularBuffer);
|
|
AK_MAKE_DEFAULT_MOVABLE(CircularBuffer);
|
|
|
|
public:
|
|
static ErrorOr<CircularBuffer> create_empty(size_t size);
|
|
static ErrorOr<CircularBuffer> create_initialized(ByteBuffer);
|
|
|
|
~CircularBuffer() = default;
|
|
|
|
size_t write(ReadonlyBytes bytes);
|
|
Bytes read(Bytes bytes);
|
|
ErrorOr<void> discard(size_t discarded_bytes);
|
|
ErrorOr<size_t> fill_from_stream(Stream&);
|
|
ErrorOr<size_t> flush_to_stream(Stream&);
|
|
|
|
/// Compared to `read()`, this starts reading from an offset that is `distance` bytes
|
|
/// before the current write pointer and allows for reading already-read data.
|
|
ErrorOr<Bytes> read_with_seekback(Bytes bytes, size_t distance);
|
|
|
|
ErrorOr<size_t> copy_from_seekback(size_t distance, size_t length);
|
|
|
|
[[nodiscard]] size_t empty_space() const;
|
|
[[nodiscard]] size_t used_space() const;
|
|
[[nodiscard]] size_t capacity() const;
|
|
[[nodiscard]] size_t seekback_limit() const;
|
|
|
|
Optional<size_t> offset_of(StringView needle, Optional<size_t> from = {}, Optional<size_t> until = {}) const;
|
|
|
|
void clear();
|
|
|
|
protected:
|
|
CircularBuffer(ByteBuffer);
|
|
|
|
[[nodiscard]] bool is_wrapping_around() const;
|
|
|
|
[[nodiscard]] Bytes next_write_span();
|
|
[[nodiscard]] ReadonlyBytes next_read_span() const;
|
|
[[nodiscard]] ReadonlyBytes next_read_span_with_seekback(size_t distance) const;
|
|
|
|
ByteBuffer m_buffer {};
|
|
|
|
size_t m_reading_head {};
|
|
size_t m_used_space {};
|
|
size_t m_seekback_limit {};
|
|
};
|
|
|
|
class SearchableCircularBuffer : public CircularBuffer {
|
|
public:
|
|
static ErrorOr<SearchableCircularBuffer> create_empty(size_t size);
|
|
static ErrorOr<SearchableCircularBuffer> create_initialized(ByteBuffer);
|
|
|
|
struct Match {
|
|
size_t distance;
|
|
size_t length;
|
|
};
|
|
/// This searches the seekback buffer (between read head and limit) for occurrences where it matches the next `length` bytes from the read buffer.
|
|
/// Supplying any hints will only consider those distances, in case existing offsets need to be validated.
|
|
/// Note that, since we only start searching at the read head, the length between read head and write head is excluded from the distance.
|
|
ErrorOr<Vector<Match>> find_copy_in_seekback(size_t maximum_length, size_t minimum_length = 2) const;
|
|
ErrorOr<Vector<Match>> find_copy_in_seekback(Vector<size_t> const& distances, size_t maximum_length, size_t minimum_length = 2) const;
|
|
|
|
private:
|
|
SearchableCircularBuffer(ByteBuffer);
|
|
};
|
|
|
|
}
|