use bstr::ByteSlice; use crate::{SecondsSinceUnixEpoch, Time}; /// Serialize this instance as string, similar to what [`write_to()`](Self::write_to()) would do.impl std::fmt::Display for Time {    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {        let mut buf = Vec::with_capacity(Time::MAX.size());        self.write_to(&mut buf).expect("write to memory cannot fail");        // SAFETY: We know time serializes as ASCII, as subset of UTF8.        #[allow(unsafe_code)]        let raw = unsafe { buf.to_str_unchecked() };        f.write_str(raw)    }} /// Serialization with standard `git` formatimpl Time {    /// Serialize this instance to `out` in a format suitable for use in header fields of serialized git commits or tags.    pub fn write_to(&self, out: &mut dyn std::io::Write) -> std::io::Result<()> {        const SECONDS_PER_HOUR: u32 = 60 * 60;        let offset = self.offset.unsigned_abs();        let hours = offset / SECONDS_PER_HOUR;        let minutes = (offset - (hours * SECONDS_PER_HOUR)) / 60;         if hours > 99 {            return Err(std::io::Error::other("Cannot represent offsets larger than +-9900"));        }         let mut itoa = itoa::Buffer::new();        out.write_all(itoa.format(self.seconds).as_bytes())?;        out.write_all(b" ")?;        out.write_all(if self.offset < 0 { b"-" } else { b"+" })?;         const ZERO: &[u8; 1] = b"0";         if hours < 10 {            out.write_all(ZERO)?;        }        out.write_all(itoa.format(hours).as_bytes())?;         if minutes < 10 {            out.write_all(ZERO)?;        }        out.write_all(itoa.format(minutes).as_bytes()).map(|_| ())    }     /// Computes the number of bytes necessary to write it using [`Time::write_to()`].    pub const fn size(&self) -> usize {        (if self.seconds >= 1_000_000_000_000_000_000 {            19        } else if self.seconds >= 100_000_000_000_000_000 {            18        } else if self.seconds >= 10_000_000_000_000_000 {            17        } else if self.seconds >= 1_000_000_000_000_000 {            16        } else if self.seconds >= 100_000_000_000_000 {            15        } else if self.seconds >= 10_000_000_000_000 {            14        } else if self.seconds >= 1_000_000_000_000 {            13        } else if self.seconds >= 100_000_000_000 {            12        } else if self.seconds >= 10_000_000_000 {            11        } else if self.seconds >= 1_000_000_000 {            10        } else if self.seconds >= 100_000_000 {            9        } else if self.seconds >= 10_000_000 {            8        } else if self.seconds >= 1_000_000 {            7        } else if self.seconds >= 100_000 {            6        } else if self.seconds >= 10_000 {            5        } else if self.seconds >= 1_000 {            4        } else if self.seconds >= 100 {            3        } else if self.seconds >= 10 {            2        } else if self.seconds >= 0 {            1            // from here, it's sign + num-digits characters        } else if self.seconds >= -10 {            2        } else if self.seconds >= -100 {            3        } else if self.seconds >= -1_000 {            4        } else if self.seconds >= -10_000 {            5        } else if self.seconds >= -100_000 {            6        } else if self.seconds >= -1_000_000 {            7        } else if self.seconds >= -10_000_000 {            8        } else if self.seconds >= -100_000_000 {            9        } else if self.seconds >= -1_000_000_000 {            10        } else if self.seconds >= -10_000_000_000 {            11        } else if self.seconds >= -100_000_000_000 {            12        } else if self.seconds >= -1_000_000_000_000 {            13        } else if self.seconds >= -10_000_000_000_000 {            14        } else if self.seconds >= -100_000_000_000_000 {            15        } else if self.seconds >= -1_000_000_000_000_000 {            16        } else if self.seconds >= -10_000_000_000_000_000 {            17        } else if self.seconds >= -100_000_000_000_000_000 {            18        } else if self.seconds >= -1_000_000_000_000_000_000 {            19        } else {            20        }) + 2 /*space + offset sign*/ + 2 /*offset hours*/ + 2 /*offset minutes*/    }     /// The numerically largest possible time instance, whose [size()](Time::size) is the largest possible    /// number of bytes to write using [`Time::write_to()`].    pub const MAX: Time = Time {        seconds: SecondsSinceUnixEpoch::MAX,        offset: 99 * 60 * 60 + 59 * 60 + 59,    };}