Change the behavior of DateTime::from_msdos when value is invalid

[sorairolake]

Is your feature request related to a problem? Please describe.
DateTime::from_msdos can create a DateTime value even if datepart or timepart is an invalid value.

zip2/src/types.rs

Lines 139 to 156 in 6c60c67

	/// Converts an msdos (u16, u16) pair to a DateTime object
	pub const fn from_msdos(datepart: u16, timepart: u16) -> DateTime {
	let seconds = (timepart & 0b0000000000011111) << 1;
	let minutes = (timepart & 0b0000011111100000) >> 5;
	let hours = (timepart & 0b1111100000000000) >> 11;
	let days = datepart & 0b0000000000011111;
	let months = (datepart & 0b0000000111100000) >> 5;
	let years = (datepart & 0b1111111000000000) >> 9;
	DateTime {
	year: years + 1980,
	month: months as u8,
	day: days as u8,
	hour: hours as u8,
	minute: minutes as u8,
	second: seconds as u8,
	}
	}

Describe the solution you'd like
I would like one of the following:

A clear and concise description of what you want to happen.

1. Make DateTime::from_msdos an unsafe function.
2. Returns Err if datepart or timepart is invalid.
3. Panics if datepart or timepart is invalid.

Describe alternatives you've considered
Specify in the documentation that an invalid DateTime value may be created.

[sorairolake]

zip2/src/types.rs

Lines 188 to 205 in 94765a4

	/// Converts an msdos (u16, u16) pair to a DateTime object if it represents a valid date and
	/// time.
	pub fn try_from_msdos(datepart: u16, timepart: u16) -> Result<DateTime, DateTimeRangeError> {
	let seconds = (timepart & 0b0000000000011111) << 1;
	let minutes = (timepart & 0b0000011111100000) >> 5;
	let hours = (timepart & 0b1111100000000000) >> 11;
	let days = datepart & 0b0000000000011111;
	let months = (datepart & 0b0000000111100000) >> 5;
	let years = (datepart & 0b1111111000000000) >> 9;
	Self::from_date_and_time(
	years.checked_add(1980).ok_or(DateTimeRangeError)?,
	months.try_into()?,
	days.try_into()?,
	hours.try_into()?,
	minutes.try_into()?,
	seconds.try_into()?,
	)
	}

This may also be defined as TryFrom<[u16; 2]> for DateTime and/or TryFrom<(u16, u16)> for DateTime.

• https://doc.rust-lang.org/std/net/struct.Ipv4Addr.html#method.new
• https://doc.rust-lang.org/std/net/struct.Ipv4Addr.html#impl-From%3C%5Bu8;+4%5D%3E-for-Ipv4Addr