/**

* Jooby https://jooby.io

* Apache License Version 2.0 https://jooby.io/LICENSE.txt

* Copyright 2014 Edgar Espina

*/

package io.jooby.internal.asm;

import org.objectweb.asm.tree.AbstractInsnNode;

import org.objectweb.asm.tree.InsnList;

import java.util.Iterator;

import java.util.Spliterator;

import java.util.function.Function;

import java.util.stream.Stream;

import java.util.stream.StreamSupport;

import static java.util.Spliterator.ORDERED;

import static java.util.Spliterators.spliteratorUnknownSize;

public class Insns {

private static class InsnIterator implements Iterator<AbstractInsnNode> {

private AbstractInsnNode node;

private Function<AbstractInsnNode, AbstractInsnNode> next;

public InsnIterator(AbstractInsnNode node,

Function<AbstractInsnNode, AbstractInsnNode> next) {

this.node = node;

this.next = next;

}

@Override public boolean hasNext() {

return node != null;

}

@Override public AbstractInsnNode next() {

AbstractInsnNode it = node;

node = next.apply(it);

return it;

}

}

public static Stream<AbstractInsnNode> next(AbstractInsnNode node) {

return stream(node, AbstractInsnNode::getNext);

}

public static Stream<AbstractInsnNode> previous(AbstractInsnNode node) {

return stream(node, AbstractInsnNode::getPrevious);

}

public static Stream<AbstractInsnNode> last(InsnList node) {

return previous(node.getLast());

}

private static Stream<AbstractInsnNode> stream(AbstractInsnNode node,

Function<AbstractInsnNode, AbstractInsnNode> next) {

Spliterator<AbstractInsnNode> iterator = spliteratorUnknownSize(

new InsnIterator(node, next),

ORDERED);

return StreamSupport.stream(iterator, false);

}

}