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
Thecdbr 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
HISTORY
Support for the cdb format first appeared
in NetBSD 6.0.
AUTHORS
The cdbr and cdbw
functions have been written by Joerg Sonnenberger
<joerg@NetBSD.org>.