package defrag

import (
	"strconv"
)

func Blocks(diskMap []byte) ([]int, error) {
	current := 0
	onFile := false
	out := []int{}
	for _, by := range diskMap {
		count, err := strconv.Atoi(string(by))
		if err != nil {
			return nil, err
		}
		onFile = !onFile

		if count == 0 {
			continue
		}
		val := -1
		if onFile {
			val = current
			current++
		}
		for idx := 0; idx < count; idx++ {
			out = append(out, val)
		}
	}
	return out, nil
}