test cznic/kv

test kv db.go

package main

import (
	"fmt"
	"github.com/cznic/kv"
	"io"
	"os"
)

func getBuf(n int) []byte {
	return make([]byte, n)
}

func openDB(dbFile string, opts *kv.Options) (*kv.DB, error) {
	createOpen := kv.Open
	status := "opening"

	if _, err := os.Stat(dbFile); os.IsNotExist(err) {
		createOpen = kv.Create
		status = "creating"
	}

	if opts == nil {
		opts = &kv.Options{}
	}

	db, err := createOpen(dbFile, opts)

	if err != nil {
		return nil, fmt.Errorf("error %s %s: %v \n", status, dbFile, err)
	}
	return db, nil
}

func main() {
	dbFile := "test.kv"

	db, err := openDB(dbFile, nil)

	defer db.Close()

	if err != nil {
		fmt.Printf("Couldn't create/open kv db at %s, error is %v \n", dbFile, err)
	}

	key := []byte("hello")
	err = db.Set(key, []byte("world"))
	if err != nil {
		fmt.Printf("Couldn't set value to db: %v \n", err)
	}

	val, err := db.Get(getBuf(200), key)
	if err != nil {
		fmt.Printf("Could't get value from db: %v \n", err)
	}
	fmt.Printf(">> %s = %s \n", key, val)

	fmt.Printf("=========== all data from begin =========== \n")

	for i := 0; i < 100; i++ {
		db.Set([]byte(string(i)), []byte(string(100-i)))
	}

	k, v, _ := db.First()
	fmt.Printf(">>First %s = %s \n", k, v)
	k, v, _ = db.Last()
	fmt.Printf(">>Last %s = %s \n", k, v)

	enum, _ := db.SeekFirst()
	k, v, _ = enum.Next()
	fmt.Printf(">> %s = %s \n", k, v)
	fmt.Printf("=========== end ========== \n")
}