iterator.go

// This file is part of GoIRS.
//
//    GoIRS is free software: you can redistribute it and/or modify
//    it under the terms of the GNU General Public License as published by
//    the Free Software Foundation, either version 3 of the License, or
//    (at your option) any later version.
//
//    GoIRS is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU General Public License for more details.
//
//    You should have received a copy of the GNU General Public License
//    along with GoIRS.  If not, see <http://www.gnu.org/licenses/>.

package goirs

//StringIterator es un iterador genérico de cadenas
type StringIterator <-chan string

const (
	//BUFFERSIZE es el tamaño del buffer de los canales
	BUFFERSIZE = 16
)

//Next devuelve el siguiente valor o la cadena vacía en caso de llegar al final
func (i StringIterator) Next() string {
	st, ok := <-i
	if ok {
		return st
	}
	return ""
}

func (i StringIterator) filter(f func(string) bool, out chan string) {
	defer close(out)
	for x := range i {
		if f(x) {
			out <- x
		}
	}
}

//Filter filtra el contenido del iterador dependiendo de la función f
func (i StringIterator) Filter(f func(string) bool) StringIterator {
	k := make(chan string, BUFFERSIZE)
	go i.filter(f, k)
	return k
}

//Evaluate cierra la cadena y evalua todo lo del iterador
//Básicamente, lo saca todo para forzar las operaciones intermedias
func (i StringIterator) Evaluate() {
	for _ = range i {
	}
}