SYNTAX
#include "cdbread.h"
void cdb_init(struct cdb *c,int fd);
int cdb_read(struct cdb *c,char *data,unsigned int dlen,uint32 pos);
int cdb_findstart(int fd,char *key,unsigned int len);
int cdb_findnext(int fd,char *key,unsigned int len);
int cdb_find(int fd,char *ney,unsigned int len);
int cdb_findnext(int fd,char *key,unsigned int len);
void cdb_free(struct cdb *c):
DESCRIPTION
cdb_free unallocates c if c is allocated. Otherwise it leaves c alone.
cdb_free does not close fd.
cdb_init allocates c to hold information about a constant database read
by descriptor fd. You may call cdb_init repeatedly; if c is already
allocated, cdb_init unallocates it first.
cdb_read reads dlen bytes into d from byte position dpos in the
database. You must allocate c before calling cdb_read. Normally
cdb_read returns 0. If the database file is shorter than dpos+dlen
bytes, or if there is a disk read error, cdb_read returns -1, setting
errno appropriately.
cdb_findstart prepares c to search for the first record under a new
key. You must allocate c before calling cdb_findstart, and you must
call cdb_findstart before calling cdb_findnext.
cdb_findnext looks for the nth record under key in the database, where
n is the number of calls to cdb_findnext after the most recent call to
cdb_findstart. If it finds the record, cdb_findnext returns 1; if
there are exactly n-1 such records, cdb_findnext returns 0; if there
are fewer than n-1 such records, the behavior of cdb_findnext is
undefined; if there is a database format error or disk error,
cdb_findnext returns -1,setting errno appropriately. Each call to
cdb_findnext (before another call to cdb_findstart) must use the same k
and klen.
If cdb_findnext returns 1, it arranges for cdb_datapos to return the
starting byte position of the data in the record, and for cdb_datalen
to return the number of bytes of data in the record. Otherwise the
results of cdb_datapos and cdb_datalen are undefined.
cdb_find is the same as cdb_findstart followed by cdb_findnext: it
finds the first record under key.
cdb_datapos and cdb_datalen are macros pointing to the found
information following key in the cdb and returning their length.
EXAMPLE
}
len = cdb_datalen(&c);
data = alloc(len);
if (!data) return -1;
if (cdb_read(&c,data,datalen,cdb_datapos(&c)) == -1) {
alloc_free(data);
return -1;
}
cdb_free(&c);
SEE ALSO
cdbmake(3)
qlibs:cdbread(3)
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