1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180

//! A trait that can be used to format an item from its components.

use core::ops::Deref;
use std::io;

use crate::format_description::well_known::Rfc3339;
use crate::format_description::FormatItem;
use crate::formatting::{format_component, format_number_pad_zero, write};
use crate::{error, Date, Time, UtcOffset};

/// A type that can be formatted.
pub trait Formattable: sealed::Sealed {}
impl Formattable for FormatItem<'_> {}
impl Formattable for [FormatItem<'_>] {}
impl Formattable for Rfc3339 {}
impl<T: Deref> Formattable for T where T::Target: Formattable {}

/// Seal the trait to prevent downstream users from implementing it.
mod sealed {
    #[allow(clippy::wildcard_imports)]
    use super::*;

    /// Format the item using a format description, the intended output, and the various components.
    #[cfg_attr(__time_03_docs, doc(cfg(feature = "formatting")))]
    pub trait Sealed {
        /// Format the item into the provided output, returning the number of bytes written.
        fn format_into(
            &self,
            output: &mut impl io::Write,
            date: Option<Date>,
            time: Option<Time>,
            offset: Option<UtcOffset>,
        ) -> Result<usize, error::Format>;

        /// Format the item directly to a `String`.
        fn format(
            &self,
            date: Option<Date>,
            time: Option<Time>,
            offset: Option<UtcOffset>,
        ) -> Result<String, error::Format> {
            let mut buf = Vec::new();
            self.format_into(&mut buf, date, time, offset)?;
            Ok(String::from_utf8_lossy(&buf).into_owned())
        }
    }
}

// region: custom formats
impl<'a> sealed::Sealed for FormatItem<'a> {
    fn format_into(
        &self,
        output: &mut impl io::Write,
        date: Option<Date>,
        time: Option<Time>,
        offset: Option<UtcOffset>,
    ) -> Result<usize, error::Format> {
        Ok(match *self {
            Self::Literal(literal) => write(output, literal)?,
            Self::Component(component) => format_component(output, component, date, time, offset)?,
            Self::Compound(items) => items.format_into(output, date, time, offset)?,
        })
    }
}

impl<'a> sealed::Sealed for [FormatItem<'a>] {
    fn format_into(
        &self,
        output: &mut impl io::Write,
        date: Option<Date>,
        time: Option<Time>,
        offset: Option<UtcOffset>,
    ) -> Result<usize, error::Format> {
        let mut bytes = 0;
        for item in self.iter() {
            bytes += item.format_into(output, date, time, offset)?;
        }
        Ok(bytes)
    }
}

impl<T: Deref> sealed::Sealed for T
where
    T::Target: sealed::Sealed,
{
    fn format_into(
        &self,
        output: &mut impl io::Write,
        date: Option<Date>,
        time: Option<Time>,
        offset: Option<UtcOffset>,
    ) -> Result<usize, error::Format> {
        self.deref().format_into(output, date, time, offset)
    }
}
// endregion custom formats

// region: well-known formats
impl sealed::Sealed for Rfc3339 {
    fn format_into(
        &self,
        output: &mut impl io::Write,
        date: Option<Date>,
        time: Option<Time>,
        offset: Option<UtcOffset>,
    ) -> Result<usize, error::Format> {
        let date = date.ok_or(error::Format::InsufficientTypeInformation)?;
        let time = time.ok_or(error::Format::InsufficientTypeInformation)?;
        let offset = offset.ok_or(error::Format::InsufficientTypeInformation)?;

        let mut bytes = 0;

        let year = date.year();

        if !(0..10_000).contains(&year) {
            return Err(error::Format::InvalidComponent("year"));
        }
        if offset.seconds_past_minute() != 0 {
            return Err(error::Format::InvalidComponent("offset_second"));
        }

        bytes += format_number_pad_zero::<_, _, 4>(output, year as u32)?;
        bytes += write(output, &[b'-'])?;
        bytes += format_number_pad_zero::<_, _, 2>(output, date.month() as u8)?;
        bytes += write(output, &[b'-'])?;
        bytes += format_number_pad_zero::<_, _, 2>(output, date.day())?;
        bytes += write(output, &[b'T'])?;
        bytes += format_number_pad_zero::<_, _, 2>(output, time.hour())?;
        bytes += write(output, &[b':'])?;
        bytes += format_number_pad_zero::<_, _, 2>(output, time.minute())?;
        bytes += write(output, &[b':'])?;
        bytes += format_number_pad_zero::<_, _, 2>(output, time.second())?;

        #[allow(clippy::if_not_else)]
        if time.nanosecond() != 0 {
            let nanos = time.nanosecond();
            bytes += write(output, &[b'.'])?;
            bytes += if nanos % 10 != 0 {
                format_number_pad_zero::<_, _, 9>(output, nanos)
            } else if (nanos / 10) % 10 != 0 {
                format_number_pad_zero::<_, _, 8>(output, nanos / 10)
            } else if (nanos / 100) % 10 != 0 {
                format_number_pad_zero::<_, _, 7>(output, nanos / 100)
            } else if (nanos / 1_000) % 10 != 0 {
                format_number_pad_zero::<_, _, 6>(output, nanos / 1_000)
            } else if (nanos / 10_000) % 10 != 0 {
                format_number_pad_zero::<_, _, 5>(output, nanos / 10_000)
            } else if (nanos / 100_000) % 10 != 0 {
                format_number_pad_zero::<_, _, 4>(output, nanos / 100_000)
            } else if (nanos / 1_000_000) % 10 != 0 {
                format_number_pad_zero::<_, _, 3>(output, nanos / 1_000_000)
            } else if (nanos / 10_000_000) % 10 != 0 {
                format_number_pad_zero::<_, _, 2>(output, nanos / 10_000_000)
            } else {
                format_number_pad_zero::<_, _, 1>(output, nanos / 100_000_000)
            }?;
        }

        if offset == UtcOffset::UTC {
            bytes += write(output, &[b'Z'])?;
            return Ok(bytes);
        }

        bytes += write(
            output,
            if offset.is_negative() {
                &[b'-']
            } else {
                &[b'+']
            },
        )?;
        bytes += format_number_pad_zero::<_, _, 2>(output, offset.whole_hours().unsigned_abs())?;
        bytes += write(output, &[b':'])?;
        bytes +=
            format_number_pad_zero::<_, _, 2>(output, offset.minutes_past_hour().unsigned_abs())?;

        Ok(bytes)
    }
}
// endregion well-known formats