mirror of
https://github.com/wiiu-env/libfat.git
synced 2024-11-25 19:36:52 +01:00
119 lines
4.1 KiB
C
119 lines
4.1 KiB
C
/*
|
|
cache.h
|
|
The cache is not visible to the user. It should be flushed
|
|
when any file is closed or changes are made to the filesystem.
|
|
|
|
This cache implements a least-used-page replacement policy. This will
|
|
distribute sectors evenly over the pages, so if less than the maximum
|
|
pages are used at once, they should all eventually remain in the cache.
|
|
This also has the benefit of throwing out old sectors, so as not to keep
|
|
too many stale pages around.
|
|
|
|
Copyright (c) 2006 Michael "Chishm" Chisholm
|
|
|
|
Redistribution and use in source and binary forms, with or without modification,
|
|
are permitted provided that the following conditions are met:
|
|
|
|
1. Redistributions of source code must retain the above copyright notice,
|
|
this list of conditions and the following disclaimer.
|
|
2. Redistributions in binary form must reproduce the above copyright notice,
|
|
this list of conditions and the following disclaimer in the documentation and/or
|
|
other materials provided with the distribution.
|
|
3. The name of the author may not be used to endorse or promote products derived
|
|
from this software without specific prior written permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
|
|
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
|
|
AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
|
|
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
|
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
|
|
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
2006-07-11 - Chishm
|
|
* Original release
|
|
*/
|
|
|
|
#ifndef _CACHE_H
|
|
#define _CACHE_H
|
|
|
|
#include "common.h"
|
|
#include "disc_io/disc_io.h"
|
|
|
|
#define CACHE_PAGE_SIZE BYTES_PER_READ
|
|
|
|
typedef struct {
|
|
u32 sector;
|
|
u32 count;
|
|
bool dirty;
|
|
} CACHE_ENTRY;
|
|
|
|
typedef struct {
|
|
const IO_INTERFACE* disc;
|
|
u32 numberOfPages;
|
|
CACHE_ENTRY* cacheEntries;
|
|
u8* pages;
|
|
} CACHE;
|
|
|
|
|
|
/*
|
|
Read data from a sector in the cache
|
|
If the sector is not in the cache, it will be swapped in
|
|
offset is the position to start reading from
|
|
size is the amount of data to read
|
|
Precondition: offset + size <= BYTES_PER_READ
|
|
*/
|
|
bool _FAT_cache_readPartialSector (CACHE* cache, void* buffer, u32 sector, u32 offset, u32 size);
|
|
|
|
/*
|
|
Write data to a sector in the cache
|
|
If the sector is not in the cache, it will be swapped in.
|
|
When the sector is swapped out, the data will be written to the disc
|
|
offset is the position to start reading from
|
|
size is the amount of data to read
|
|
Precondition: offset + size <= BYTES_PER_READ
|
|
*/
|
|
bool _FAT_cache_writePartialSector (CACHE* cache, const void* buffer, u32 sector, u32 offset, u32 size);
|
|
|
|
/*
|
|
Write data to a sector in the cache, zeroing the sector first
|
|
If the sector is not in the cache, it will be swapped in.
|
|
When the sector is swapped out, the data will be written to the disc
|
|
offset is the position to start reading from
|
|
size is the amount of data to read
|
|
Precondition: offset + size <= BYTES_PER_READ
|
|
*/
|
|
bool _FAT_cache_eraseWritePartialSector (CACHE* cache, const void* buffer, u32 sector, u32 offset, u32 size);
|
|
|
|
/*
|
|
Read a full sector from the cache
|
|
*/
|
|
static inline bool _FAT_cache_readSector (CACHE* cache, void* buffer, u32 sector) {
|
|
return _FAT_cache_readPartialSector (cache, buffer, sector, 0, BYTES_PER_READ);
|
|
}
|
|
|
|
/*
|
|
Write a full sector to the cache
|
|
*/
|
|
static inline bool _FAT_cache_writeSector (CACHE* cache, const void* buffer, u32 sector) {
|
|
return _FAT_cache_writePartialSector (cache, buffer, sector, 0, BYTES_PER_READ);
|
|
}
|
|
|
|
/*
|
|
Write any dirty sectors back to disc and clear out the contents of the cache
|
|
*/
|
|
bool _FAT_cache_flush (CACHE* cache);
|
|
|
|
/*
|
|
Clear out the contents of the cache without writing any dirty sectors first
|
|
*/
|
|
void _FAT_cache_invalidate (CACHE* cache);
|
|
|
|
CACHE* _FAT_cache_constructor (u32 numberOfPages, const IO_INTERFACE* discInterface);
|
|
|
|
void _FAT_cache_destructor (CACHE* cache);
|
|
|
|
#endif // _CACHE_H
|