115 lines
2.8 KiB
C
115 lines
2.8 KiB
C
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/* public interfaces for block io routines */
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#ifndef _BLOCK_H
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#define _BLOCK_H
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/*#define IBEX_STATS*/ /* define to get/dump block access stats */
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#include <glib.h>
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/* version of file format */
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#define IBEX_VERSION "ibx6"
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typedef guint32 nameid_t;
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typedef guint32 blockid_t;
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#define BLOCK_BITS (8)
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#define BLOCK_SIZE (1<<BLOCK_BITS)
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#define CACHE_SIZE 256 /* blocks in disk cache */
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/* root block */
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struct _root {
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char version[4];
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blockid_t free; /* list of free blocks */
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blockid_t roof; /* top of allocated space, everything below is in a free or used list */
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blockid_t tail; /* list of 'tail' blocks */
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blockid_t words; /* root of words index */
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blockid_t names; /* root of names index */
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char flags; /* state flags */
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/* makes structure fill up to 1024 bytes */
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char dummy[1024 - (sizeof(char)*5) - (sizeof(blockid_t)*5)];
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};
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#define IBEX_ROOT_SYNCF (1<<0) /* file is synced */
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/* basic disk structure for (data) blocks */
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struct _block {
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unsigned int next:32-BLOCK_BITS; /* next block */
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unsigned int used:BLOCK_BITS; /* number of elements used */
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nameid_t bl_data[(BLOCK_SIZE-4)/4]; /* references */
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};
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/* custom list structure, for a simple/efficient cache */
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struct _listnode {
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struct _listnode *next;
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struct _listnode *prev;
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};
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struct _list {
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struct _listnode *head;
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struct _listnode *tail;
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struct _listnode *tailpred;
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};
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void ibex_list_new(struct _list *v);
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struct _listnode *ibex_list_addhead(struct _list *l, struct _listnode *n);
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struct _listnode *ibex_list_addtail(struct _list *l, struct _listnode *n);
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struct _listnode *ibex_list_remove(struct _listnode *n);
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/* in-memory structure for block cache */
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struct _memblock {
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struct _memblock *next;
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struct _memblock *prev;
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blockid_t block;
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int flags;
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struct _block data;
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};
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#define BLOCK_DIRTY (1<<0)
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struct _memcache {
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struct _list nodes;
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int count; /* nodes in cache */
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GHashTable *index; /* blockid->memblock mapping */
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int fd; /* file fd */
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#ifdef IBEX_STATS
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GHashTable *stats;
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#endif
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struct _root root; /* root block */
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/* temporary here */
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struct _IBEXWord *words; /* word index */
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};
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#ifdef IBEX_STATS
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struct _stat_info {
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int read;
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int write;
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int cache_hit;
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int cache_miss;
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};
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#endif /* IBEX_STATS */
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struct _memcache *ibex_block_cache_open(const char *name, int flags, int mode);
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void ibex_block_cache_close(struct _memcache *block_cache);
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void ibex_block_cache_sync(struct _memcache *block_cache);
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void ibex_block_cache_flush(struct _memcache *block_cache);
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blockid_t ibex_block_get(struct _memcache *block_cache);
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void ibex_block_free(struct _memcache *block_cache, blockid_t blockid);
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void ibex_block_dirty(struct _block *block);
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struct _block *ibex_block_read(struct _memcache *block_cache, blockid_t blockid);
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#define block_number(x) ((x)>>BLOCK_BITS)
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#define block_location(x) ((x)<<BLOCK_BITS)
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#endif /* ! _BLOCK_H */
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