CDBR(3) FreeBSD Library Functions Manual CDBR(3)
NAME
cdbr, cdbr_open, cdbr_open_mem, cdbr_entries, cdbr_get, cdbr_find,
cdbr_close - constant database access methods
SYNOPSIS
struct cdbr *
cdbr_open(const char *path, int flags);
struct cdbr *
cdbr_open_mem(void *base, size_t size, int flags,
void (*unmap)(void *, void *, size_t), void *cookie);
uint32_t
cdbr_entries(struct cdbr *cdbr);
int
cdbr_get(struct cdbr *cdbr, uint32_t index, const void **data,
size_t *datalen);
int
cdbr_find(struct cdbr *cdbr, const void *key, size_t keylen,
const void **data, size_t *datalen);
void
cdbr_close(struct cdbr *cdbr);
DESCRIPTION
The 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.
SEE ALSO
nbperf(1), cdbw(3), db(3), cdb(5)
HISTORY
Support for the cdb format first appeared in NetBSD 6.0.
AUTHORS
The cdbr and cdbw functions have been written by Joerg Sonnenberger
<
[email protected]>.
FreeBSD 14.1-RELEASE-p8 December 1, 2018 FreeBSD 14.1-RELEASE-p8