Complete Unzip module

# -*- coding: utf-8 -*-
# Author João S. O. Bueno <jsbueno(at)python.org.br>
# Licensed under Creative Commons Attribution Required

def unzip(seq):
    start = True
    for next in seq:
        if start:
            result = [[] for _ in xrange(len(next))]
            start = False
        for i,v in enumerate(next):
            result[i].append(v)
    return result

def xunzip(seq):
    it = iter(seq)
    next = it.next()
    width = len(next)
    results = []
    buffer_ = [{"tuple": next, "consumed": 0}]
    # This is a list to workaround the non-existence
    # of the "nonlocal" keyword in python 2
    buffer_base = [0]
    for i in xrange(width):
        def freeze_i(j):
            def unzipper():
                offset = 0
                while True:
                    index = offset - buffer_base[0]
                    if not (offset < len(buffer_) + buffer_base[0]):
                        buffer_.append({"tuple": it.next(), "consumed": 0})
                    buffer_[index]["consumed"] += 1
                    value = buffer_[index]["tuple"][j]
                    if buffer_[index]["consumed"] == width:
                        buffer_.pop(0)
                        buffer_base[0] += 1
                    yield value
                    offset += 1
            unzipper.func_name = "seq_%d" % j
            return unzipper
        results.append(freeze_i(i)())
    return results


if __name__ == "__main__":
    import random
    a = zip(range(10), range(10,20), range(20,30))
    print unzip(a)
    b = xunzip(a)
    finished_count = [0,0,0]
    unpack = [-1, -1, -1]
    while sum(finished_count) < len(b):
        index = random.randrange(len(b))
        try:
            unpack[index] = b[index].next()
            buffer_lenght = len(b[index].gi_frame.f_locals["buffer_"])
        except StopIteration:
            finished_count[index] = 1
            buffer_lenght = "Unknown"
        print unpack, "Buffer lenght: ", buffer_lenght