ExtSort

Example:

import(
 "fmt"
 "github.com/bsm/extsort"
)
func main() {
	// Init sorter.
	sorter := extsort.New(nil)
	defer sorter.Close()
	// Append plain data.
	_ = sorter.Append([]byte("foo"))
	_ = sorter.Append([]byte("bar"))
	_ = sorter.Append([]byte("baz"))
	_ = sorter.Append([]byte("dau"))
	// Sort and iterate.
	iter, err := sorter.Sort()
	if err != nil {
		panic(err)
	}
	defer iter.Close()
	for iter.Next() {
		fmt.Println(string(iter.Data()))
	}
	if err := iter.Err(); err != nil {
		panic(err)
	}
}

import(
 "fmt"
 "github.com/bsm/extsort"
)
func main() {
	// Init with de-duplication.
	sorter := extsort.New(&extsort.Options{
		Dedupe: bytes.Equal,
	})
	defer sorter.Close()
	// Put key/value data.
	_ = sorter.Put([]byte("foo"), []byte("v1"))
	_ = sorter.Put([]byte("bar"), []byte("v2"))
	_ = sorter.Put([]byte("baz"), []byte("v3"))
	_ = sorter.Put([]byte("bar"), []byte("v4"))	// duplicate
	_ = sorter.Put([]byte("dau"), []byte("v5"))
	// Sort and iterate.
	iter, err := sorter.Sort()
	if err != nil {
		panic(err)
	}
	defer iter.Close()
	for iter.Next() {
		fmt.Println(string(iter.Key()), string(iter.Value()))
	}
	if err := iter.Err(); err != nil {
		panic(err)
	}
}