mirror of
https://github.com/RGBCube/serenity
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69 lines
2.1 KiB
C++
69 lines
2.1 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "NullDevice.h"
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#include <AK/Singleton.h>
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#include <AK/StdLibExtras.h>
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namespace Kernel {
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static AK::Singleton<NullDevice> s_the;
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UNMAP_AFTER_INIT void NullDevice::initialize()
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{
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s_the.ensure_instance();
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}
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NullDevice& NullDevice::the()
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{
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return *s_the;
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}
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UNMAP_AFTER_INIT NullDevice::NullDevice()
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: CharacterDevice(1, 3)
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{
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}
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UNMAP_AFTER_INIT NullDevice::~NullDevice()
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{
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}
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bool NullDevice::can_read(const FileDescription&, size_t) const
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{
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return true;
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}
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KResultOr<size_t> NullDevice::read(FileDescription&, size_t, UserOrKernelBuffer&, size_t)
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{
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return 0;
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}
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KResultOr<size_t> NullDevice::write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t buffer_size)
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{
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return min(static_cast<size_t>(PAGE_SIZE), buffer_size);
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}
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}
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