gecko-dev/db/examples/ex_btrec.c
1998-10-15 03:56:37 +00:00

247 lines
5.2 KiB
C

/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997, 1998
* Sleepycat Software. All rights reserved.
*
* @(#)ex_btrec.c 10.8 (Sleepycat) 4/11/98
*/
#include "config.h"
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#endif
#include <db.h>
#define DATABASE "access.db"
#define WORDLIST "../test/wordlist"
DB_ENV *db_init __P((char *));
int main __P((int, char *[]));
void show __P((char *, DBT *, DBT *));
void usage __P((void));
const char *progname = "ex_btrec"; /* Program name. */
int
main(argc, argv)
int argc;
char *argv[];
{
extern char *optarg;
extern int errno, optind;
DB *dbp;
DBC *dbcp;
DBT key, data;
DB_ENV *dbenv;
DB_INFO dbinfo;
FILE *fp;
db_recno_t recno;
u_int32_t len;
int ch, cnt;
char *home, *p, *t, buf[1024], rbuf[1024];
home = NULL;
while ((ch = getopt(argc, argv, "h:")) != EOF)
switch (ch) {
case 'h':
home = optarg;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
/* Open the word database. */
if ((fp = fopen(WORDLIST, "r")) == NULL) {
fprintf(stderr,
"%s: %s: %s\n", progname, WORDLIST, strerror(errno));
exit (1);
}
/* Remove the previous database. */
(void)unlink(DATABASE);
/* Initialize the database environment. */
dbenv = db_init(home);
/* Initialize the database. */
memset(&dbinfo, 0, sizeof(dbinfo));
dbinfo.db_cachesize = 32 * 1024; /* Cachesize: 32K. */
dbinfo.db_pagesize = 1024; /* Page size: 1K. */
dbinfo.flags |= DB_RECNUM; /* Record numbers! */
/* Create the database. */
if ((errno = db_open(DATABASE,
DB_BTREE, DB_CREATE, 0664, dbenv, &dbinfo, &dbp)) != 0) {
fprintf(stderr,
"%s: %s: %s\n", progname, DATABASE, strerror(errno));
exit (1);
}
/*
* Insert records into the database, where the key is the word
* preceded by its record number, and the data is the same, but
* in reverse order.
*/
memset(&key, 0, sizeof(DBT));
memset(&data, 0, sizeof(DBT));
for (cnt = 1; cnt <= 1000; ++cnt) {
(void)sprintf(buf, "%04d_", cnt);
if (fgets(buf + 4, sizeof(buf) - 4, fp) == NULL)
break;
if ((len = strlen(buf)) <= 1)
continue;
for (t = rbuf, p = buf + (len - 2); p >= buf;)
*t++ = *p--;
*t++ = '\0';
key.data = buf;
data.data = rbuf;
data.size = key.size = len - 1;
switch (errno =
dbp->put(dbp, NULL, &key, &data, DB_NOOVERWRITE)) {
case 0:
break;
default:
fprintf(stderr,
"%s: put: %s\n", progname, strerror(errno));
exit (1);
case DB_KEYEXIST:
printf("%s: key already exists\n", buf);
break;
}
}
/* Close the word database. */
(void)fclose(fp);
/* Acquire a cursor for the database. */
if ((errno = dbp->cursor(dbp, NULL, &dbcp)) != 0) {
fprintf(stderr, "%s: cursor: %s\n", progname, strerror(errno));
exit (1);
}
/*
* Prompt the user for a record number, then retrieve and display
* that record.
*/
for (;;) {
/* Get a record number. */
printf("recno #> ");
fflush(stdout);
if (fgets(buf, sizeof(buf), stdin) == NULL)
break;
recno = atoi(buf);
/*
* Reset the key each time, the dbp->c_get() routine returns
* the key and data pair, not just the key!
*/
key.data = &recno;
key.size = sizeof(recno);
if ((errno = dbcp->c_get(dbcp, &key, &data, DB_SET_RECNO)) != 0)
goto err;
/* Display the key and data. */
show("k/d\t", &key, &data);
/* Move the cursor a record forward. */
if ((errno = dbcp->c_get(dbcp, &key, &data, DB_NEXT)) != 0)
goto err;
/* Display the key and data. */
show("next\t", &key, &data);
/*
* Retrieve the record number for the following record into
* local memory.
*/
data.data = &recno;
data.size = sizeof(recno);
data.ulen = sizeof(recno);
data.flags |= DB_DBT_USERMEM;
if ((errno = dbcp->c_get(dbcp, &key, &data, DB_GET_RECNO)) != 0)
err: switch (errno) {
case DB_NOTFOUND:
fprintf(stderr,
"%s: get: record not found\n", progname);
continue;
case DB_KEYEMPTY:
fprintf(stderr,
"%s: get: key empty/deleted\n", progname);
continue;
default:
fprintf(stderr,
"%s: get: %s\n", progname, strerror(errno));
exit (1);
}
printf("retrieved recno: %lu\n", (u_long)recno);
/* Reset the data DBT. */
memset(&data, 0, sizeof(data));
}
(void)dbcp->c_close(dbcp);
(void)dbp->close(dbp, 0);
return (db_appexit(dbenv));
}
/*
* show --
* Display a key/data pair.
*/
void
show(msg, key, data)
DBT *key, *data;
char *msg;
{
printf("%s%.*s : %.*s\n", msg,
(int)key->size, (char *)key->data,
(int)data->size, (char *)data->data);
}
/*
* db_init --
* Initialize the environment.
*/
DB_ENV *
db_init(home)
char *home;
{
DB_ENV *dbenv;
/* Rely on calloc to initialize the structure. */
if ((dbenv = (DB_ENV *)calloc(sizeof(DB_ENV), 1)) == NULL) {
fprintf(stderr, "%s: %s\n", progname, strerror(ENOMEM));
exit (1);
}
dbenv->db_errfile = stderr;
dbenv->db_errpfx = progname;
if ((errno = db_appinit(home, NULL, dbenv, DB_CREATE)) != 0) {
fprintf(stderr,
"%s: db_appinit: %s\n", progname, strerror(errno));
exit (1);
}
return (dbenv);
}
void
usage()
{
(void)fprintf(stderr, "usage: %s [-h home]\n", progname);
exit(1);
}