Source code for rics.performance._format_perf_counter

from time import perf_counter

FORMAT_AS_MINUTE_LIMIT = 60.0
FORMAT_SECOND_SINGLE_DECIMAL = 1.0
FORMAT_SECOND_DOUBLE_DECIMAL = 0.5




def format_perf_counter(start: float, end: float | None = None) -> str:
    """Format performance counter output.

    This function formats performance counter output based on the time elapsed. For ``t < 120 sec``, accuracy is
    increased whereas for durations above one minute a more user-friendly formatting is used.

    Args:
        start: Start time.
        end: End time. Set to now if not given.

    Returns:
        A formatted performance counter time.

    Examples:
        >>> format_perf_counter(0, 309613.49)
        '3d 14h 0m 13s'
        >>> format_perf_counter(0, 0.154)
        '154ms'
        >>> format_perf_counter(0, 31.39)
        '31.4s'

    See Also:
        :py:func:`time.perf_counter`

    """
    t = (end or perf_counter()) - start
    return format_seconds(t)





def format_seconds(t: float, *, allow_negative: bool = False) -> str:  # noqa: PLR0911
    """Format performance counter output.

    This function formats performance counter output based on the time elapsed. For ``t < 120 sec``, accuracy is
    increased whereas for durations above one minute a more user-friendly formatting is used.

    Args:
        t: Time in seconds.
        allow_negative: If ``True``, format negative `t` with a leading minus sign.

    Returns:
        A formatted performance counter time.

    Raises:
        ValueError: If ``t < 0`` and ``allow_negative=False`` (the default).

    """
    if t < 0:
        if not allow_negative:
            allow_negative = True
            raise ValueError(f"Refuse to format {t=} < 0; to allow, set {allow_negative=}")
        return f"-{format_seconds(abs(t))}"

    if t > FORMAT_AS_MINUTE_LIMIT:
        days, seconds = divmod(round(t), 86400)
        hours, seconds = divmod(seconds, 3600)
        minutes, seconds = divmod(seconds, 60)

        parts = (days, hours, minutes, seconds)
        nonzero = tuple(p > 0 for p in parts)
        start, stop = nonzero.index(True), len(nonzero) - nonzero[::-1].index(True)
        return " ".join(f"{parts[i]}{'dhms'[i]}" for i in range(start, stop))

    if t >= FORMAT_SECOND_SINGLE_DECIMAL:
        return f"{t:.1f}s"
    if t > FORMAT_SECOND_DOUBLE_DECIMAL:
        return f"{t:.2f}s"
    if t > 10**-3:
        return f"{t * 10 ** 3:.0f}ms"
    if t > 10**-6:  # 1 μs
        return f"{t * 10 ** 6:.0f}μs"
    if t > 10**-9:
        return f"{t * 10 ** 9:.0f}ns"

    return f"{t:.3g}s"