import gras
import numpy

class add_2x(gras.Block):
    def __init__(self, sig):
        gras.Block.__init__(self,
            name = "add 2x",
            in_sig = [sig, sig],
            out_sig = [sig],
        )

    def work(self, ins, outs):
        nitems = min(*map(len, (ins[0], ins[1], outs[0])))
        outs[0][:nitems] = ins[0][:nitems] + ins[1][:nitems]
        self.consume(0, nitems)
        self.consume(1, nitems)
        self.produce(0, nitems)

class NullSource(gras.Block):
    def __init__(self, out_sig):
        gras.Block.__init__(self, 'NullSource', out_sig=[out_sig])

    def work(self, ins, outs):
        outs[0][:] = numpy.zeros(len(outs[0]))
        self.produce(0, len(outs[0]))

class NullSink(gras.Block):
    def __init__(self, in_sig):
        gras.Block.__init__(self, 'NullSink', in_sig=[in_sig])

    def work(self, ins, outs):
        self.consume(0, len(ins[0]))

class VectorSource(gras.Block):
    def __init__(self, out_sig, vec):
        gras.Block.__init__(self, name='VectorSource', out_sig=[out_sig])
        self._vec = vec

    def work(self, ins, outs):
        num = min(len(outs[0]), len(self._vec))
        outs[0][:num] = self._vec[:num]
        self.produce(0, num)
        self._vec = self._vec[num:]
        if not self._vec:
            self.mark_done()

class VectorSink(gras.Block):
    def __init__(self, in_sig):
        gras.Block.__init__(self, name='VectorSink', in_sig=[in_sig])
        self._vec = list()

    def get_vector(self):
        return tuple(self._vec)

    def work(self, ins, outs):
        self._vec.extend(ins[0].copy())
        self.consume(0, len(ins[0]))