1 files changed, 118 insertions, 0 deletions
diff --git a/sdk-modifications/include/fs_cache.h b/sdk-modifications/include/fs_cache.h
new file mode 100755
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+++ b/sdk-modifications/include/fs_cache.h
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+/*
+ 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 "fs_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