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/*************************************************************************************************
* Example for advanced operations of the hash database
*
* Copyright 2020 Google LLC
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of the License at
* https://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software distributed under the
* License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied. See the License for the specific language governing permissions
* and limitations under the License.
*************************************************************************************************/
#include "tkrzw_cmd_util.h"
#include "tkrzw_dbm_hash.h"
#include "tkrzw_str_util.h"
// Main routine.
int main(int argc, char** argv) {
// All symbols of Tkrzw are under the namespace "tkrzw".
using namespace tkrzw;
// Creates the database manager.
HashDBM dbm;
// Opens a new database,
dbm.Open("casket.tkh", true, File::OPEN_TRUNCATE);
// Record processor to count events.
class Counter : public DBM::RecordProcessor {
public:
// Update an existing record.
virtual std::string_view ProcessFull(std::string_view key, std::string_view value) {
new_value_ = ToString(StrToInt(value) + 1);
return new_value_;
}
// Register a new record.
virtual std::string_view ProcessEmpty(std::string_view key) {
return "1";
}
private:
std::string new_value_;
};
// Procedure to count up an event.
// DBM::IncrementSimple does the same job.
const auto CountUp = [&](std::string_view name) {
Counter counter;
dbm.Process(name, &counter, true);
};
// Counts up events.
CountUp("foo");
CountUp("foo");
CountUp("bar");
// Reports counts.
std::cout << dbm.GetSimple("foo", "0") << std::endl;
std::cout << dbm.GetSimple("bar", "0") << std::endl;
std::cout << dbm.GetSimple("baz", "0") << std::endl;
// Closes the database.
dbm.Close();
return 0;
}
// END OF FILE
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