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