52 lines
1.6 KiB
C++
52 lines
1.6 KiB
C++
#pragma once
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#include "../../main.h"
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#include "../../cppruntime/runtime.hpp"
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namespace helos {
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// BlockDevice describes random-access storage devices organizing data in blocks of uniform sizes.
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class BlockDevice {
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public:
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virtual ~BlockDevice() {}
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// BlockSize returns the size, in bytes, of the data block.
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// It is to remain constant throughout the lifetime of the device.
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virtual uint64_t BlockSize() const = 0;
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// Size returns the size, in blocks, of the entire device.
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virtual uint64_t Size() const = 0;
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// SizeBytes returns the size of the entire device in bytes.
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virtual uint64_t SizeBytes() const {
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return BlockSize() * Size();
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}
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// Permission returns the permission on the entire device (Read, Write, Exec)
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virtual Permission DevicePermission() const {
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return PermRead | PermWrite | PermExecute;
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}
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// ReadBlock reads, from the block device, blockCount blocks of data into the buffer.
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//
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// Returns the number of blocks read, or a negative number on error.
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virtual uint64_t ReadBlock(uint64_t blockOffset, void *data, uint64_t blockCount) const = 0;
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// WriteBlock writes into the block device blockCount blocks.
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//
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// Returns the number of blocks written, or a negative number on error.
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// (no data is written on error)
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virtual uint64_t WriteBlock(uint64_t blockOffset, const void *data, uint64_t blockCount) = 0;
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public:
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// Slice creates a new BlockDevice reading from a portion of the underlying device.
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// The underlying device must be kept alive as long as the slice exists.
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BlockDevice *Slice(uint64_t blockOffset, uint64_t blockCount);
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};
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} // namespace helos
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