"""Calculate timing statistics from a list of execution times.

This function computes key statistical measures including mean, median, standard deviation, minimum, and maximum from a list of execution times. If the input list is empty, it returns a dictionary with all values set to 0.

Args:
    times (list[float]): A list of execution times as floating-point numbers.

Returns:
    dict[str, float]: A dictionary containing the following keys:
        - 'mean': The arithmetic mean of the execution times.
        - 'median': The median of the execution times.
        - 'std_dev': The standard deviation of the execution times. Returns 0 if the list contains fewer than 2 elements.
        - 'min': The minimum execution time.
        - 'max': The maximum execution time.

Examples:
    >>> times = [1.0, 2.0, 3.0, 4.0, 5.0]
    >>> stats = calculate_stats(times)
    >>> stats['mean']
    3.0
    >>> stats['median']
    3.0
"""