Paper/src/main/java/net/minecraft/server/ItemStep.java

package net.minecraft.server;

public class ItemStep extends ItemBlock {

    public ItemStep(int i) {
        super(i);
        this.setMaxDurability(0);
        this.a(true);
    }

    public int filterData(int i) {
        return i;
    }

    public String a(ItemStack itemstack) {
        int i = itemstack.getData();

        if (i < 0 || i >= BlockStep.a.length) {
            i = 0;
        }

        return super.getName() + "." + BlockStep.a[i];
    }

    public boolean interactWith(ItemStack itemstack, EntityHuman entityhuman, World world, int i, int j, int k, int l) {
        if (itemstack.count == 0) {
            return false;
        } else if (!entityhuman.d(i, j, k)) {
            return false;
        } else {
            int i1 = world.getTypeId(i, j, k);
            int j1 = world.getData(i, j, k);
            int k1 = j1 & 7;
            boolean flag = (j1 & 8) != 0;

            if ((l == 1 && !flag || l == 0 && flag) && i1 == Block.STEP.id && k1 == itemstack.getData()) {
                /* CraftBukkit start - handle this in super
                if (world.containsEntity(Block.DOUBLE_STEP.e(world, i, j, k)) && world.setTypeIdAndData(i, j, k, Block.DOUBLE_STEP.id, k1)) {
                    world.makeSound((double) ((float) i + 0.5F), (double) ((float) j + 0.5F), (double) ((float) k + 0.5F), Block.DOUBLE_STEP.stepSound.getName(), (Block.DOUBLE_STEP.stepSound.getVolume1() + 1.0F) / 2.0F, Block.DOUBLE_STEP.stepSound.getVolume2() * 0.8F);
                    --itemstack.count;
                }

                return true;
                */
                return super.interactWith(itemstack, entityhuman, world, i, j, k, -1);
                // CraftBukkit end
            } else {
                return b(itemstack, entityhuman, world, i, j, k, l) ? true : super.interactWith(itemstack, entityhuman, world, i, j, k, l);
            }
        }
    }

    private static boolean b(ItemStack itemstack, EntityHuman entityhuman, World world, int i, int j, int k, int l) {
        if (l == 0) {
            --j;
        }

        if (l == 1) {
            ++j;
        }

        if (l == 2) {
            --k;
        }

        if (l == 3) {
            ++k;
        }

        if (l == 4) {
            --i;
        }

        if (l == 5) {
            ++i;
        }

        int i1 = world.getTypeId(i, j, k);
        int j1 = world.getData(i, j, k);
        int k1 = j1 & 7;

        if (i1 == Block.STEP.id && k1 == itemstack.getData()) {
            if (world.containsEntity(Block.DOUBLE_STEP.e(world, i, j, k)) && world.setTypeIdAndData(i, j, k, Block.DOUBLE_STEP.id, k1)) {
                world.makeSound((double) ((float) i + 0.5F), (double) ((float) j + 0.5F), (double) ((float) k + 0.5F), Block.DOUBLE_STEP.stepSound.getName(), (Block.DOUBLE_STEP.stepSound.getVolume1() + 1.0F) / 2.0F, Block.DOUBLE_STEP.stepSound.getVolume2() * 0.8F);
                --itemstack.count;
            }

            return true;
        } else {
            return false;
        }
    }
}