Manual browser: cdbr(3)
|CDBR(3)||Library Functions Manual||CDBR(3)|
NAMEcdbr cdbr_open, cdbr_open_mem, cdbr_entries, cdbr_get, cdbr_find, cdbr_close, cdbr_write — constant database access methods
SYNOPSISstruct cdbr *
cdbr_open(const char *path, int flags);
struct cdbr *
cdbr_open_mem(void *base, size_t size, void (*unmap)(void *, void *, size_t), void *cookie);
cdbr_entries(struct cdbr *cdbr);
cdbr_get(struct cdbr *cdbr, uint32_t index, const void **data, size_t *datalen);
cdbr_find(struct cdbr *cdbr, const void *key, size_t keylen, const void **data, size_t *datalen);
cdbr_close(struct cdbr *cdbr);
DESCRIPTIONThe cdbr library provides a space efficient (key,value) database based on perfect hashing.
A cdb database is opened for reading by calling cdbr_open(). The only supported value for flags is CDBR_DEFAULT. The function returns a handle to pass to the other functions. The database is closed by invoking cdbr_close(). All resources associated with the handle are freed and the memory returned by cdbr_get() and cdbr_find() is invalidated. cdbr_open_mem() works like cdbr_open(), but takes a memory reference to the content of the database file. If unmap is not NULL, it is called by cdbr_close() with cookie, base and size as arguments. It is not called by cdbr_open_mem() on error.
The number of records in the database can be obtained by calling cdbr_entries(). Records can be obtained by record number using cdbr_get() or by key using cdbr_find(). Both functions return 0 on success and update data and datalen accordingly. The location *data remains valid until cdbr_close() is called. It is the responsibility of the caller of cdbr_find() to ensure that the key matches the returned data. The function returns the only possible match, but the database doesn't store the keys to minimize overhead.
HISTORYSupport for the cdb format first appeared in NetBSD 6.0.
AUTHORSThe cdbr and cdbw functions have been written by <joerg@NetBSD.org>.
|December 5, 2013||NetBSD 7.0|