Add KV basic sample.

samples/kvdb_basic_sample.c

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2020, Armink, <armink.ztl@gmail.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief basic KV samples.
+ *
+ * basic Key-Value Database KV feature samples
+ */
+
+#include <flashdb.h>
+
+#ifdef FDB_USING_KVDB
+
+#define FDB_LOG_TAG "[sample][kvdb][basic]"
+
+void kvdb_basic_sample(fdb_kvdb_t kvdb)
+{
+    struct fdb_blob blob;
+    int boot_count = 0;
+
+    { /* GET the KV value */
+        /* get the "boot_count" KV value */
+        fdb_kv_get_blob(kvdb, "boot_count", fdb_blob_make(&blob, &boot_count, sizeof(boot_count)));
+        /* the blob.saved.len is more than 0 when get the value successful */
+        if (blob.saved.len > 0) {
+            FDB_INFO("get the 'boot_count' value is %d\n", boot_count);
+        } else {
+            FDB_INFO("get the 'boot_count' failed\n");
+        }
+    }
+
+    { /* CHANGE the KV value */
+        /* increase the boot count */
+        boot_count ++;
+        /* change the "boot_count" KV's value */
+        fdb_kv_set_blob(kvdb, "boot_count", fdb_blob_make(&blob, &boot_count, sizeof(boot_count)));
+        FDB_INFO("set the 'boot_count' value to %d\n", boot_count);
+    }
+}
+
+#endif /* FDB_USING_KVDB */