TestKeyRange.cpp

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1997-2005
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: TestKeyRange.cpp,v 12.1 2005/06/16 20:24:11 bostic Exp $
 */

/*
 * NOTE: AccessExample changed to test Db.key_range.  We made a global
 * change of /AccessExample/TestKeyRange/, the only other changes are
 * marked with comments that are notated as 'ADDED'.
 */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <iostream.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#ifndef _MSC_VER
#include <unistd.h>
#endif
#endif

#include <iomanip.h>
#include <db_cxx.h>

class TestKeyRange
{
public:
        TestKeyRange();
        void run();

private:
        static const char FileName[];

        // no need for copy and assignment
        TestKeyRange(const TestKeyRange &);
        void operator = (const TestKeyRange &);
};

static void usage();          // forward

int main(int argc, char *argv[])
{
        if (argc > 1) {
                usage();
        }

        // Use a try block just to report any errors.
        // An alternate approach to using exceptions is to
        // use error models (see DbEnv::set_error_model()) so
        // that error codes are returned for all Berkeley DB methods.
        //
        try {
                TestKeyRange app;
                app.run();
                return 0;
        }
        catch (DbException &dbe) {
                cerr << "TestKeyRange: " << dbe.what() << "\n";
                return 1;
        }
}

static void usage()
{
        cerr << "usage: TestKeyRange\n";
        exit(1);
}

const char TestKeyRange::FileName[] = "access.db";

TestKeyRange::TestKeyRange()
{
}

void TestKeyRange::run()
{
        // Remove the previous database.
        (void)unlink(FileName);

        // Create the database object.
        // There is no environment for this simple example.
        Db db(0, 0);

        db.set_error_stream(&cerr);
        db.set_errpfx("TestKeyRange");
        db.set_pagesize(1024);          /* Page size: 1K. */
        db.set_cachesize(0, 32 * 1024, 0);
        db.open(NULL, FileName, NULL, DB_BTREE, DB_CREATE, 0664);

        //
        // Insert records into the database, where the key is the user
        // input and the data is the user input in reverse order.
        //
        char buf[1024];
        char rbuf[1024];
        char *t;
        char *p;
        int ret;
        int len;
        Dbt *firstkey = NULL;
        char firstbuf[1024];

        for (;;) {
                cout << "input>";
                cout.flush();

                cin.getline(buf, sizeof(buf));
                if (cin.eof())
                        break;

                if ((len = strlen(buf)) <= 0)
                        continue;
                for (t = rbuf, p = buf + (len - 1); p >= buf;)
                        *t++ = *p--;
                *t++ = '\0';

                Dbt key(buf, len + 1);
                Dbt data(rbuf, len + 1);
                if (firstkey == NULL) {
                        strcpy(firstbuf, buf);
                        firstkey = new Dbt(firstbuf, len + 1);
                }

                ret = db.put(0, &key, &data, DB_NOOVERWRITE);
                if (ret == DB_KEYEXIST) {
                        cout << "Key " << buf << " already exists.\n";
                }
                cout << "\n";
        }

        // We put a try block around this section of code
        // to ensure that our database is properly closed
        // in the event of an error.
        //
        try {
                // Acquire a cursor for the table.
                Dbc *dbcp;
                db.cursor(NULL, &dbcp, 0);

                /*ADDED...*/
                DB_KEY_RANGE range;
                memset(&range, 0, sizeof(range));

                db.key_range(NULL, firstkey, &range, 0);
                printf("less: %f\n", range.less);
                printf("equal: %f\n", range.equal);
                printf("greater: %f\n", range.greater);
                /*end ADDED*/

                Dbt key;
                Dbt data;

                // Walk through the table, printing the key/data pairs.
                while (dbcp->get(&key, &data, DB_NEXT) == 0) {
                        char *key_string = (char *)key.get_data();
                        char *data_string = (char *)data.get_data();
                        cout << key_string << " : " << data_string << "\n";
                }
                dbcp->close();
        }
        catch (DbException &dbe) {
                cerr << "TestKeyRange: " << dbe.what() << "\n";
        }

        db.close(0);
}

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