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// timespan - A simple timespan for chrono times. // // Copyright (C) 2017 // Fin Christensen <christensen.fin@gmail.com> // // This program is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program. If not, see <http://www.gnu.org/licenses/>. use crate::DelayedFormat; use crate::Error; use crate::Formatable; use crate::Parsable; use crate::Spanable; use chrono::Duration; use regex; use regex::Regex; use std; /// This describes a span of something that is `Spanable` by providing a start and end point. /// /// When the provided `Spanable` type `T` is `Formatable` the span can be serialized to /// a string. For deserialization from a string the `Parsable` trait must be implemented by `T`. /// Support for `serde` is available when the `timespan` crate is configured with the /// `with-serde` feature. /// /// This type implements operations known from the set theory. However, there are only operations /// allowed that produce a single span (e.g. the resulting span is continuous) that must not be /// empty. When an operation would violate these restrictions an error is emitted. /// /// > Developer note: A `Span` may accept all possible input values without leading to errors in /// > the future by producing an iterator over the results allowing an arbitrary amount of /// > resulting spans. /// /// # Example /// /// ~~~~ /// # extern crate timespan; extern crate chrono; fn main() { /// use timespan::Span; /// use chrono::NaiveTime; /// /// let start = "12:30:00".parse().unwrap(); /// let end = "14:45:00".parse().unwrap(); /// let span: Span<NaiveTime> = Span::new(start, end).unwrap(); /// /// assert!(format!("{}", span) == "12:30:00 - 14:45:00"); /// # } /// ~~~~ #[derive(PartialEq, Clone)] pub struct Span<T> { /// The starting point of the span. pub start: T, /// The end point of the span. pub end: T, } impl<T> Span<T> where T: Spanable, { /// Create a new span with a given starting point and a given end point. /// /// This method emits an `Error::Ordering` error when the end point lies /// before the start point. pub fn new(start: T, end: T) -> Result<Span<T>, Error> { if start >= end { return Err(Error::Ordering); } Ok(Span { start: start, end: end, }) } /// Get the total duration of the span as a `chrono::Duration`. pub fn duration(&self) -> Duration { self.end.signed_duration_since(self.start) } /// Calculate the mathematical difference of two spans with the same `Spanable` type. /// /// The difference of span `self` and `other` includes the parts of span `self` that are /// not included in span `other`. /// /// This method produces an error when /// /// - the resulting difference would produce an empty span (`Error::Empty`) /// - the resulting difference is not continuous (e.g. splitted) (`Error::NotContinuous`) /// pub fn difference(&self, other: &Span<T>) -> Result<Span<T>, Error> { if self.start >= other.start && self.end <= other.end { // -(--[-]--)- -> err return Err(Error::Empty); } else if self.end <= other.start { // -[##]-(--)- return Ok(self.clone()); } else if self.start >= other.end { // -(--)-[##]- return Ok(self.clone()); } else if self.end > other.start && self.end <= other.end && self.start < other.start { // -[##(-]--)- return Ok(Span { start: self.start, end: other.start, }); } else if self.start >= other.start && self.start < other.end && self.end > other.end { // -(--[-)##]- return Ok(Span { start: other.end, end: self.end, }); } else { // -[##(-)##]- -> err return Err(Error::NotContinuous); } } /// Calculate the mathematical symmetric difference of two spans with the same `Spanable` type. /// /// The symmetric difference of span `self` and `other` includes the parts of span `self` that /// are not included in span `other` and the parts of span `other` that are not included in span /// `self`. /// /// This method produces an error when the resulting symmetric difference is not continuous /// (e.g. splitted) (`Error::NotContinuous`). As this is only not the case when the two spans /// are adjacent this method will most likely produce an error. pub fn symmetric_difference(&self, other: &Span<T>) -> Result<Span<T>, Error> { if self.end == other.start { // -[##](##)- return Ok(Span { start: self.start, end: other.end, }); } else if other.end == self.start { // -(##)[##]- return Ok(Span { start: other.start, end: self.end, }); } else { return Err(Error::NotContinuous); } } /// Calculate the mathematical intersection of two spans with the same `Spanable` type. /// /// The intersection of span `self` and `other` includes the parts that are included in span `self` /// and span `other`. /// /// This method produces an `Error::Empty` error when there is no intersection between the /// two spans. pub fn intersection(&self, other: &Span<T>) -> Result<Span<T>, Error> { if self.end <= other.start || other.end <= self.start { Err(Error::Empty) } else { Ok(Span { start: std::cmp::max(self.start, other.start), end: std::cmp::min(self.end, other.end), }) } } /// Calculate the mathematical union of two spans with the same `Spanable` type. /// /// The union of span `self` and `other` includes the parts that are included in span `self` or /// span `other`. /// /// This method produces an `Error::NotContinuous` error when the two spans are not intersecting /// or adjacent to each other. pub fn union(&self, other: &Span<T>) -> Result<Span<T>, Error> { if self.end < other.start || other.end < self.start { Err(Error::NotContinuous) } else { Ok(Span { start: std::cmp::min(self.start, other.start), end: std::cmp::max(self.end, other.end), }) } } /// Returns `true` when a given `Spanable` is included in `self`. Otherwise returns `false`. pub fn contains(&self, item: &T) -> bool { self.start <= *item && self.end >= *item } /// Returns `true` when `self` has no parts in common with `other`. Otherwise returns `false`. pub fn is_disjoint(&self, other: &Span<T>) -> bool { self.end <= other.start || self.start >= other.end } /// Returns `true` when `self` is completely included in `other`. Otherwise returns `false`. pub fn is_subset(&self, other: &Span<T>) -> bool { self.start >= other.start && self.end <= other.end } /// Returns `true` when `other` is completely included in `self`. Otherwise returns `false`. pub fn is_superset(&self, other: &Span<T>) -> bool { self.start <= other.start && self.end >= other.end } /// Split `self` at a given time point `at` into two spans of the same `Spanable` type. /// /// This emits an `Error::OutOfRange` error when `at` is not included in `self`. pub fn split_off(&self, at: &T) -> Result<(Span<T>, Span<T>), Error> { if self.start >= *at || self.end <= *at { return Err(Error::OutOfRange); } Ok(( Span { start: self.start, end: *at, }, Span { start: *at, end: self.end, }, )) } /// Move the end point forward in time by a given duration. /// /// This emits an `Error::Empty` error when the operation would produce an empty span /// (e.g. the duration is negative). pub fn append(&mut self, time: &Duration) -> Result<(), Error> { let new = self.end + *time; if new <= self.start { return Err(Error::Empty); } self.end = new; Ok(()) } /// Move the start point backward in time by a given duration. /// /// This emits an `Error::Empty` error when the operation would produce an empty span. /// (e.g. the duration is negative). pub fn prepend(&mut self, time: &Duration) -> Result<(), Error> { let new = self.start - *time; if new >= self.end { return Err(Error::Empty); } self.start = new; Ok(()) } /// Move the end point backward in time by a given duration. /// /// This emits an `Error::Empty` error when the operation would produce an empty span. pub fn pop(&mut self, time: &Duration) -> Result<(), Error> { let new = self.end - *time; if new <= self.start { return Err(Error::Empty); } self.end = new; Ok(()) } /// Move the start point forward in time by a given duration. /// /// This emits an `Error::Empty` error when the operation would produce an empty span. pub fn shift(&mut self, time: &Duration) -> Result<(), Error> { let new = self.start + *time; if new >= self.end { return Err(Error::Empty); } self.start = new; Ok(()) } } impl<T> Span<T> where T: Spanable + Formatable, { /// Formats the span with the specified format strings. /// /// For the `start` and `end` format strings see the `chrono::format::strftime` module. /// /// The `fmt` string is used to format the span to a string. It must contain the following /// substrings: /// /// - `{start}` to match the `start` point of the span /// - `{end}` to match the `end` point of the span /// /// # Example /// /// ~~~~ /// # extern crate timespan; fn main() { /// use timespan::NaiveTimeSpan; /// /// let span: NaiveTimeSpan = "12:30:00 - 14:45:00".parse().unwrap(); /// /// let f = span.format("from {start} to {end}", "%H.%M", "%H.%M"); /// assert!(f.to_string() == "from 12.30 to 14.45"); /// assert!(format!("{}", f) == "from 12.30 to 14.45"); /// # } /// ~~~~ pub fn format<'a>(&self, fmt: &'a str, start: &'a str, end: &'a str) -> DelayedFormat<'a, T> { DelayedFormat { span: self.clone(), fmt: fmt, start: start, end: end, } } } impl<T> Span<T> where T: Spanable + Parsable, { /// Parses the span with the specified format strings from a given string `s`. /// /// For the `start` and `end` format strings see the `chrono::format::strftime` module. /// /// The `fmt` string is used to parse a span from a string. It must contain the following /// substrings: /// /// - `{start}` to match the `start` point of the span /// - `{end}` to match the `end` point of the span /// /// # Example /// ~~~~ /// # extern crate timespan; fn main() { /// use timespan::NaiveTimeSpan; /// /// let span = NaiveTimeSpan::parse_from_str( /// "from 12.30 to 14.45", /// "from {start} to {end}", /// "%H.%M", /// "%H.%M", /// ).unwrap(); /// /// assert!(format!("{}", span) == "12:30:00 - 14:45:00"); /// # } /// ~~~~ pub fn parse_from_str(s: &str, fmt: &str, start: &str, end: &str) -> Result<Span<T>, Error> { let esc = regex::escape(fmt); let repl_re = Regex::new(r"(?:\\\{start\\\}|\\\{end\\\})").unwrap(); let repl = repl_re.replace_all(&esc, r"(.*)"); let re = Regex::new(&repl)?; let caps = re.captures(s).ok_or(Error::Empty)?; let start_idx = fmt.find("{start}").ok_or(Error::NoStart)?; let end_idx = fmt.find("{end}").ok_or(Error::NoEnd)?; // we already checked for the existance of {start} and {end} captures -> unwrap allowed let m1 = caps.get(1).unwrap(); let m2 = caps.get(2).unwrap(); if start_idx < end_idx { Span::new( T::parse_from_str(m1.as_str(), start)?, T::parse_from_str(m2.as_str(), end)?, ) } else { Span::new( T::parse_from_str(m2.as_str(), start)?, T::parse_from_str(m1.as_str(), end)?, ) } } } /// Parses a `Span` from a string in the format `{start} - {end}`. impl<T> std::str::FromStr for Span<T> where T: Spanable + Parsable, { type Err = Error; fn from_str(s: &str) -> Result<Self, Self::Err> { let re = Regex::new(r"(.*)\s+-\s+(.*)").unwrap(); let caps = re.captures(s).ok_or(Error::Empty)?; let c1 = caps.get(1).ok_or(Error::NoStart)?; let c2 = caps.get(2).ok_or(Error::NoEnd)?; Span::new(T::from_str(c1.as_str())?, T::from_str(c2.as_str())?) } } /// Formats a `Span` in the format `{start} - {end}`. impl<T> std::fmt::Debug for Span<T> where T: Spanable + Formatable, { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { write!(f, "{} - {}", self.start, self.end) } } /// Formats a `Span` in the format `{start} - {end}`. impl<T> std::fmt::Display for Span<T> where T: Spanable + Formatable, { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { std::fmt::Debug::fmt(self, f) } } #[cfg(feature = "with-serde")] mod with_serde { use super::Formatable; use super::Parsable; use super::Span; use super::Spanable; use serde::{de, ser}; use std::fmt; use std::marker::PhantomData; impl<T> ser::Serialize for Span<T> where T: Spanable + Formatable, { fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: ser::Serializer, { serializer.collect_str(&self) } } struct SpanVisitor<T> { phantom: PhantomData<T>, } impl<'de, T> de::Visitor<'de> for SpanVisitor<T> where T: Spanable + Parsable, { type Value = Span<T>; fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { write!(formatter, "a formatted time span string") } fn visit_str<E>(self, value: &str) -> Result<Span<T>, E> where E: de::Error, { value.parse().map_err(|err| E::custom(format!("{}", err))) } } impl<'de, T> de::Deserialize<'de> for Span<T> where T: Spanable + Parsable, { fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: de::Deserializer<'de>, { deserializer.deserialize_str(SpanVisitor { phantom: PhantomData, }) } } }