Levigo iter range start/end, updated from https://github.com/janelia-flyem/dvid/blob/master/storage/levigo.go

ter_range.go

package main
import (
    "log"
    "fmt"
    "bytes"
//    "strconv"
    "github.com/jmhodges/levigo"
)


type KeyValue struct {
	Key 	string
	Value 	string
}

func GetRange(db *levigo.DB, kStart []byte, kEnd []byte) (values []KeyValue, err error) {
    values = []KeyValue{}
    ro := levigo.NewReadOptions()
    defer ro.Close()

	it := db.NewIterator(ro)
    defer func() {
        it.Close()
    }()
	it.Seek(kStart)
    endBytes := kEnd
    for {
        if it.Valid() {
            if bytes.Compare(it.Key(), endBytes) > 0 {
                return
            }
            value := it.Value()
            vstr := string(value[:])
            key := it.Key()
            kstr := string(key[:])
            values = append(values, KeyValue{kstr, vstr})
            it.Next()
        } else {
            err = it.GetError()
            return
        }
    }

    return
}

func main() {
	log.Println("Starting")
	    // Setup LevelDB
    opts := levigo.NewOptions()
    opts.SetCreateIfMissing(true)
    filter := levigo.NewBloomFilter(10)
    opts.SetFilterPolicy(filter)
    db, err := levigo.Open("/work/opensource/blockchain_playground_golang/tmpdat2", opts)

    defer db.Close()

    if err != nil {
        fmt.Printf("failed to load db: %s\n", err)
    }
    
    wo := levigo.NewWriteOptions()
    //wo.SetSync(true)
    defer wo.Close()

    ro := levigo.NewReadOptions()
    defer ro.Close()

    wb := levigo.NewWriteBatch()
    defer wb.Close()

    kStart := []byte("last")
    kEnd := []byte("last\xff")

    values, err := GetRange(db, kStart, kEnd)
    if err != nil {
    	fmt.Printf("GetRange error: %s\n", err)
    }

    for _, kv := range values {
    	log.Println(kv)
    }

}