mirror of
https://github.com/SerenityOS/serenity
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121 lines
4.4 KiB
C++
121 lines
4.4 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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#pragma once
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// KBuffer: Statically sized kernel-only memory buffer.
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//
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// A KBuffer is a value-type convenience class that wraps a NonnullRefPtr<KBufferImpl>.
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// The memory is allocated via the global kernel-only page allocator, rather than via
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// kmalloc() which is what ByteBuffer/Vector/etc will use.
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//
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// This makes KBuffer a little heavier to allocate, but much better for large and/or
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// long-lived allocations, since they don't put all that weight and pressure on the
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// severely limited kmalloc heap.
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#include <AK/Assertions.h>
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#include <AK/LogStream.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/Region.h>
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class KBufferImpl : public RefCounted<KBufferImpl> {
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public:
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static NonnullRefPtr<KBufferImpl> create_with_size(size_t size, u8 access, const char* name)
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{
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auto region = MM.allocate_kernel_region(PAGE_ROUND_UP(size), name, access, false, false);
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ASSERT(region);
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return adopt(*new KBufferImpl(region.release_nonnull(), size));
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}
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static NonnullRefPtr<KBufferImpl> copy(const void* data, size_t size, u8 access, const char* name)
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{
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auto buffer = create_with_size(size, access, name);
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memcpy(buffer->data(), data, size);
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return buffer;
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}
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u8* data() { return m_region->vaddr().as_ptr(); }
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const u8* data() const { return m_region->vaddr().as_ptr(); }
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size_t size() const { return m_size; }
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size_t capacity() const { return m_region->size(); }
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void set_size(size_t size)
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{
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ASSERT(size <= capacity());
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m_size = size;
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}
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private:
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explicit KBufferImpl(NonnullOwnPtr<Region>&& region, size_t size)
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: m_size(size)
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, m_region(move(region))
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{
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}
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size_t m_size { 0 };
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NonnullOwnPtr<Region> m_region;
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};
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class KBuffer {
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public:
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static KBuffer create_with_size(size_t size, u8 access = Region::Access::Read | Region::Access::Write, const char* name = "KBuffer")
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{
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return KBuffer(KBufferImpl::create_with_size(size, access, name));
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}
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static KBuffer copy(const void* data, size_t size, u8 access = Region::Access::Read | Region::Access::Write, const char* name = "KBuffer")
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{
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return KBuffer(KBufferImpl::copy(data, size, access, name));
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}
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u8* data() { return m_impl->data(); }
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const u8* data() const { return m_impl->data(); }
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size_t size() const { return m_impl->size(); }
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size_t capacity() const { return m_impl->capacity(); }
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void set_size(size_t size) { m_impl->set_size(size); }
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const KBufferImpl& impl() const { return m_impl; }
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KBuffer(const ByteBuffer& buffer, u8 access = Region::Access::Read | Region::Access::Write, const char* name = "KBuffer")
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: m_impl(KBufferImpl::copy(buffer.data(), buffer.size(), access, name))
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{
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}
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private:
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explicit KBuffer(NonnullRefPtr<KBufferImpl>&& impl)
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: m_impl(move(impl))
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{
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}
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NonnullRefPtr<KBufferImpl> m_impl;
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};
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inline const LogStream& operator<<(const LogStream& stream, const KBuffer& value)
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{
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return stream << StringView(value.data(), value.size());
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}
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