CDBW(3)

NAME
cdbw_open, cdbw_put, cdbw_put_data, cdbw_put_key, cdbw_stable_seeder, cdbw_output, cdbw_close - create constant databases

SYNOPSIS
#include <cdbw.h>
struct cdbw *
cdbw_open(void);
int
cdbw_put(struct cdbw *cdbw, const void *key, size_t keylen, const void *data, size_t datalen);
int
cdbw_put_data(struct cdbw *cdbw, const void *data, size_t datalen, uint32_t *index);
int
cdbw_put_key(struct cdbw *cdbw, const void *key, size_t keylen, uint32_t index);
uint32_t
cdbw_stable_seeder(void);
int
cdbw_output(struct cdbw *cdbw, int output, const char *descr, uint32_t (*seedgen)(void));
void
cdbw_close(struct cdbw *cdbw);

DESCRIPTION
The cdbw functions are used to create a constant databases for use with cdbr(3). Details about the file format, including overhead and limitations, can be found in cdb(5).

cdbw_open() prepares a new cdb writer. The function returns a handle to pass to the other functions.

cdbw_close() frees all resources associated with the handle.

cdbw_put() adds the given (key,value) pair after checking for a duplicate key. cdbw_put_data() adds the given value to the writer without adding a key reference. The returned index can be used in subsequent calls to cdbw_put_key() to add one or more keys pointing to this value. cdbw_put_key() checks for duplicate keys and valid index arguments. On success it adds the given key.

cdbw_output() computes the database file and writes it to the given descriptor. The function returns an error if the file cannot be written correctly. The descr parameter, a string of up to 16 bytes, provides a human readable description of the database content. The seedgen parameter can be used to override the default PRNG. The bitwise layout of the output depends on the chosen seed. The function should return a different value for each invocation. The cdbw_stable_seeder() can be used to create reproducible output. It may be slower than the default.

SEE ALSO
cdbr(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 <joerg@NetBSD.org>.