import gzip, bz2

def myopen(filename, mode="r", bufsize=-1):
    """
    open(), detecting .gz and .bz2 file suffixes
    """
    if filename[-3:] == ".gz":
        return gzip.open(filename, mode, bufsize)
    elif filename[-4:] == ".bz2":
        return bz2.open(filename, mode, bufsize)
    else:
        return open(filename, mode, bufsize)

def find_files(dir, shuffle=False):
    """
    Find all files in dir by recursively directory walking.
    @param shuffle: Randomly shuffle the files before returning them.
    """
    files = []
    for root, dirs, files in os.walk(dir):
        #sys.stderr.write("Walking %s...\n" % root)
        for f in files:
            files.append(os.path.join(root, f))
    if shuffle:
        import random
        random.shuffle(files)
    return files

def ensuredir(dir):
    """
    Create dir if it does not exist (including all parents).
    Do nothing if it does.
    """
    if not os.path.exists(dir):
       sys.stderr.write("Creating directory: %s\n" % dir)
       os.makedirs(dir)
    assert os.path.isdir(dir)