buffered_file_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/io/buffered_location_reader.hxx>
#include <StormByte/buffer/visibility.h>
 
#include <chrono>
#include <fstream>
#include <mutex>
#include <optional>
#include <utility>
 
namespace StormByte {
    namespace Buffer {
        namespace IO {
            class STORMBYTE_BUFFER_PUBLIC BufferedFileReader final: public BufferedLocationReader {
                public:
                    class Parameters: public BufferedLocationReader::Parameters {
                        public:
                            using BufferedLocationReader::Parameters::Parameters;
                    };
 
                    STORMBYTE_FORCE_INLINE explicit BufferedFileReader(StormByte::String::String path,
                            Parameters parameters = {}):
                        BufferedLocationReader(std::move(path), Location::Local,
                            parameters.ReadAhead().value_or(StormByte::ByteSize{0}),
                            parameters.MaxMemory().value_or(StormByte::ByteSize{1024ull * 1024ull}),
                            parameters.MaxWait().value_or(std::chrono::milliseconds{0}),
                            !parameters.ReadAhead().has_value()) {}
 
                    BufferedFileReader(const BufferedFileReader&) = delete;
 
                    BufferedFileReader(BufferedFileReader&& other) noexcept;
 
                    ~BufferedFileReader() noexcept override;
 
                    BufferedFileReader& operator=(const BufferedFileReader&) = delete;
 
                    BufferedFileReader& operator=(BufferedFileReader&& other) noexcept;
 
                protected:
                    StormByte::Shared<StormByte::System::Device> OriginDevice() const override;
 
                    Result OriginOpen() override;
 
                    Result OriginClose() override;
 
                    Result OriginPull(StormByte::ByteSize n, FIFO& dest) override;
 
                    Result OriginSeek(std::ptrdiff_t offset, Position mode) override;
 
                    std::optional<StormByte::ByteSize> OriginSize() const noexcept override;
 
                private:
                    std::ifstream m_file;                       
                    std::optional<StormByte::ByteSize> m_size;  
                    mutable std::mutex m_file_mutex;            
            };
        }
    }
}