vellum example usage

vellum_example_usage.go

package main

import (
	"bytes"

	"github.com/couchbaselabs/vellum"
	vregex "github.com/couchbaselabs/vellum/regexp"
)

func main() {
	var fstBuffer bytes.Buffer
	builder, err := vellum.New(&fstBuffer, nil)
	if err != nil {
		panic(err)
	}
  
  // 5 is len(field) ...
	insert := []byte("5field")
	insert = append(insert, []byte("value")...)
	if err := builder.Insert(insert, 1); err != nil {
		panic(err)
	}

	if err := builder.Close(); err != nil {
		panic(err)
	}

	fst, err := vellum.Load(fstBuffer.Bytes())
	if err != nil {
		panic(err)
	}

	regex := []byte("5field")
	regex = append(regex, []byte("val.*")...)
	re, err := vregex.New(string(regex))
	if err != nil {
		panic(err)
	}

	minKey := append([]byte("5field"))
	maxKey := append([]byte("5fiele"))

	iter, err := fst.Search(re, minKey, maxKey)
	if err != nil {
		panic(err)
	}

	for {
		_, offset := iter.Current()
		println("offset", offset)

		err = iter.Next()
		if err == vellum.ErrIteratorDone {
			break
		}
		if err != nil {
			panic(err)
		}
	}

	if err := iter.Close(); err != nil {
		panic(err)
	}

	println("all done!")
}

func not_working_main() {
	var fstBuffer bytes.Buffer
	builder, err := vellum.New(&fstBuffer, nil)
	if err != nil {
		panic(err)
	}

	insert := []byte("field")
	insert = append(insert, byte(0xff))
	insert = append(insert, []byte("value")...)
	if err := builder.Insert(insert, 1); err != nil {
		panic(err)
	}

	if err := builder.Close(); err != nil {
		panic(err)
	}

	fst, err := vellum.Load(fstBuffer.Bytes())
	if err != nil {
		panic(err)
	}

	regex := []byte("field")
	regex = append(regex, byte(0xff))
	regex = append(regex, []byte("val.*")...)
	re, err := vregex.New(string(regex))
	if err != nil {
		panic(err)
	}

	minKey := append([]byte("field"), byte(0xff), byte(0))
	maxKey := append([]byte("field"), byte(0xff), byte(0xff))

	iter, err := fst.Search(re, minKey, maxKey)
	if err != nil {
		panic(err)
	}

	for {
		_, offset := iter.Current()
		println("offset", offset)

		err = iter.Next()
		if err == vellum.ErrIteratorDone {
			break
		}
		if err != nil {
			panic(err)
		}
	}

	if err := iter.Close(); err != nil {
		panic(err)
	}

	println("all done!")
}