1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
|
/*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'.
*/
/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997-2002
* Sleepycat Software. All rights reserved.
*
* $Id: TestKeyRange.cpp,v 1.4 2002/01/23 14:26:41 bostic Exp $
*/
#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);
}
|
