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janwas
58360a629c
- use helper functions to reduce occurrences of BLOCK_SIZE and SECTOR_SIZE - wmi: provide for shutting it down (gets rid of its two threads); only initialize if actually needed (costs 200ms) - ogl_tex: don't complain if there's no gfx_card info (due to not having used wmi) This was SVN commit r5572.
36 lines
1.1 KiB
C++
36 lines
1.1 KiB
C++
#ifndef INCLUDED_IO_ALIGN
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#define INCLUDED_IO_ALIGN
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#include "lib/bits.h" // IsAligned, round_up
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/**
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* block := power-of-two sized chunk of a file.
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* all transfers are expanded to naturally aligned, whole blocks.
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* (this makes caching parts of files feasible; it is also much faster
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* for some aio implementations, e.g. wposix.)
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* (blocks are also thereby page-aligned, which allows write-protecting
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* file buffers without worrying about their boundaries.)
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**/
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static const size_t BLOCK_SIZE = 256*KiB;
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// note: *sizes* and *offsets* are aligned to blocks to allow zero-copy block cache.
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// that the *buffer* need only be sector-aligned (we assume 4kb for simplicity)
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// (this is a requirement of the underlying Windows OS)
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static const size_t SECTOR_SIZE = 4*KiB;
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template<class T>
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bool IsAligned_Data(T* address)
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{
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return IsAligned((uintptr_t)address, SECTOR_SIZE);
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}
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extern bool IsAligned_Offset(off_t ofs);
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extern off_t AlignedOffset(off_t ofs);
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extern off_t AlignedSize(off_t size);
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extern off_t PaddedSize(off_t size, off_t ofs);
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#endif // #ifndef INCLUDED_IO_ALIGN
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