rom/filesys/fat/cache.h

   1 /*
   2     Copyright © 2010, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Disk cache.
   6 */
   7
   8 #ifndef CACHE_H
   9 #define CACHE_H
  10
  11 #include <exec/types.h>
  12 #include <exec/lists.h>
  13
  14 struct BlockRange
  15 {
  16     struct MinNode node1;    /* links into hash table */
  17     struct MinNode node2;    /* links into free and dirty lists */
  18     ULONG use_count;    /* number of users of this block */
  19     UWORD state;
  20     ULONG num;    /* start block number */
  21     UBYTE *data;    /* actual block data */
  22 };
  23
  24 struct Cache
  25 {
  26     ULONG block_count;    /* number of blocks allocated */
  27     ULONG block_size;    /* size of a disk block */
  28     ULONG hash_size;    /* size of hash table */
  29     struct BlockRange **blocks;    /* array of pointers to all blocks */
  30     struct MinList *hash_table;    /* hash table of all valid cache blocks */
  31     struct MinList dirty_list;    /* the dirty list */
  32     struct MinList free_list;    /* the free list */
  33 };
  34
  35 /* Block states */
  36
  37 #define BS_EMPTY 0
  38 #define BS_VALID 1
  39 #define BS_DIRTY 2
  40
  41 /* Prototypes */
  42
  43 APTR Cache_CreateCache(ULONG hash_size, ULONG block_count, ULONG block_size);
  44 VOID Cache_DestroyCache(APTR cache);
  45 APTR Cache_GetBlock(APTR cache, ULONG blockNum, UBYTE **data);
  46 VOID Cache_FreeBlock(APTR cache, APTR block);
  47 VOID Cache_MarkBlockDirty(APTR cache, APTR block);
  48 BOOL Cache_Flush(APTR cache);
  49
  50 #endif