buffered_reader.hxx

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/*
 * Copyright (C) 2024-2026 David C. Manuelda (StormBytePP)
 *
 * This file is part of StormByte-Buffer.
 *
 * StormByte-Buffer original source is dual-licensed:
 *
 * 1. GNU Lesser General Public License v3.0 (or later)
 *    You may redistribute and/or modify this file under the terms of the
 *    GNU Lesser General Public License as published by the Free Software
 *    Foundation, either version 3 of the License, or (at your option)
 *    any later version.
 *
 * 2. Commercial license
 *    Alternatively, this file may be used under the terms of a commercial
 *    license agreement with the copyright holder
 *    (David C. Manuelda <StormByte@gmail.com>).
 *
 * Both licenses apply only to original StormByte-Buffer source in this
 * repository. They do not cover other StormByte modules or any third-party
 * material shipped with this repository (including everything under
 * thirdparty/, and in particular the bundled StormByte-Logger tree and
 * the rest of the StormByte suite it vendors), which remains under its own
 * license.
 *
 * Neither license grants any patent rights. Any patent licenses required
 * to use this software or third-party components must be obtained separately
 * from the patent holders.
 *
 * StormByte-Buffer is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * version 3 along with StormByte-Buffer. If not, see
 * <https://www.gnu.org/licenses/lgpl-3.0.html>.
 *
 * SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-StormByte-Commercial
 */
 
#pragma once
 
#include <StormByte/buffer/fifo.hxx>
#include <StormByte/buffer/io/parameters.hxx>
#include <StormByte/buffer/io/telemetry.hxx>
#include <StormByte/buffer/io/typedefs.hxx>
#include <StormByte/buffer/telemetry.hxx>
#include <StormByte/buffer/typedefs.hxx>
#include <StormByte/buffer/visibility.h>
#include <StormByte/safe_pointers.hxx>
#include <StormByte/string/string.hxx>
 
#include <chrono>
#include <cstddef>
#include <memory>
#include <optional>
#include <span>
#include <utility>
 
namespace StormByte {
    namespace Buffer {
        namespace Backend {
            namespace IO {
                class BufferedReader;
            }
        }
 
        namespace IO {
            class STORMBYTE_BUFFER_PUBLIC BufferedReader {
                friend class StormByte::Buffer::Backend::IO::BufferedReader;
 
                public:
                    class Parameters: public ReaderParameters {
                        public:
                            using ReaderParameters::ReaderParameters;
                    };
 
                    BufferedReader(const BufferedReader&) = delete;
 
                    BufferedReader(BufferedReader&& other) noexcept;
 
                    virtual ~BufferedReader() noexcept;
 
                    BufferedReader& operator=(const BufferedReader&) = delete;
 
                    BufferedReader& operator=(BufferedReader&& other) noexcept;
 
                    const StormByte::String::String& Path() const noexcept;
 
                    enum Location Location() const noexcept;
 
                    virtual explicit operator bool() const noexcept final;
 
                    virtual enum State State() const noexcept final;
 
                    virtual bool Open() final;
 
                    virtual Result Close() final;
 
                    virtual bool Rewind() final;
 
                    virtual bool IsOpen() const noexcept final;
 
                    virtual bool IsReadable() const noexcept final;
 
                    virtual bool EoF() const noexcept final;
 
                    virtual StormByte::ByteSize Available() const noexcept final;
 
                    virtual Result Read(StormByte::ByteSize n, FIFO& dest) const final;
 
                    virtual Result Read(std::span<std::byte> dest) const final;
 
                    virtual Result Peek(StormByte::ByteSize n, FIFO& dest) const final;
 
                    virtual Result Peek(std::span<std::byte> dest) const final;
 
                    virtual Result Seek(std::ptrdiff_t offset, Position mode) const final;
 
                    virtual StormByte::ByteSize Tell() const noexcept final;
 
                    virtual bool IsSeekable() const noexcept final;
 
                    virtual bool IsSized() const noexcept final;
 
                    virtual std::optional<StormByte::ByteSize> Size() const noexcept final;
 
                    const StormByte::Shared<StormByte::Buffer::ReadTelemetry> Telemetry() const noexcept;
 
                    virtual StormByte::ByteSize ReadAhead() const noexcept;
 
                    virtual void ReadAhead(StormByte::ByteSize bytes);
 
                    virtual StormByte::ByteSize MaxMemory() const noexcept;
 
                    virtual void MaxMemory(StormByte::ByteSize bytes);
 
                    virtual std::chrono::milliseconds MaxWait() const noexcept;
 
                    virtual void MaxWait(std::chrono::milliseconds wait);
 
                protected:
                    STORMBYTE_FORCE_INLINE BufferedReader(StormByte::String::String path, enum Location location,
                            Parameters parameters = {}):
                        BufferedReader(std::move(path), location,
                            parameters.ReadAhead().value_or(StormByte::ByteSize{0}),
                            parameters.MaxMemory().value_or(StormByte::ByteSize{0}),
                            parameters.MaxWait().value_or(std::chrono::milliseconds{0})) {}
 
                    BufferedReader(StormByte::String::String path, enum Location location,
                        StormByte::ByteSize read_ahead, StormByte::ByteSize max_memory,
                        std::chrono::milliseconds max_wait);
 
                    void SetState(enum State state) noexcept;
 
                    virtual void Setup();
 
                    virtual StormByte::Shared<StormByte::Buffer::ReadTelemetry> CreateTelemetry() const;
 
                    virtual Result OriginOpen() = 0;
 
                    virtual Result OriginClose() = 0;
 
                    virtual Result OriginPull(StormByte::ByteSize n, FIFO& dest) = 0;
 
                    virtual bool OriginCanSeek() const noexcept = 0;
 
                    virtual Result OriginSeek(std::ptrdiff_t offset, Position mode) = 0;
 
                    virtual bool OriginHasSize() const noexcept = 0;
 
                    virtual std::optional<StormByte::ByteSize> OriginSize() const noexcept = 0;
 
                private:
                    std::unique_ptr<StormByte::Buffer::Backend::IO::BufferedReader> m_io;   
            };
        }
    }
}