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#![no_std] #![warn(clippy::indexing_slicing)] //! This library provides several useful constructs to format data in a human-readable fashion with //! zero allocations //! //! Some of these functions may seem to partly reinvent existing std functionality, for example //! [`join`]: //! //! ```rust //! println!("{}", display_utils::join(&[1, 2, 3], " + ")); // display_utils //! println!("{}", ["1", "2", "3"].join(" + ")); // std //! //! println!("{}", display_utils::repeat("abc", 4)); // display_utils //! println!("{}", "abc".repeat(4)); // std //! ``` //! //! The important difference is that the std approach involves 4 allocations, whereas the //! display_utils approach operates 100% on stack and is therefore no_std compatible and likely //! faster. /// Print a loading-style bar using Unicode block characters. /// /// The bar is very high-resolution: 8 states can be represented per character. /// /// Accepts the total length of the bar and a float from 0.0 to 1.0 as the filled proportion. /// /// Prints exactly max_length chars (not bytes!), right-padded with spaces. /// /// ```rust /// # use display_utils::*; /// assert_eq!(unicode_block_bar(13, 0.0).to_string(), " "); /// assert_eq!(unicode_block_bar(13, 0.1).to_string(), "█▎ "); /// assert_eq!(unicode_block_bar(13, 0.2).to_string(), "██▌ "); /// assert_eq!(unicode_block_bar(13, 0.3).to_string(), "███▉ "); /// assert_eq!(unicode_block_bar(13, 0.4).to_string(), "█████▏ "); /// assert_eq!(unicode_block_bar(13, 0.5).to_string(), "██████▌ "); /// assert_eq!(unicode_block_bar(13, 0.6).to_string(), "███████▊ "); /// assert_eq!(unicode_block_bar(13, 0.7).to_string(), "█████████ "); /// assert_eq!(unicode_block_bar(13, 0.8).to_string(), "██████████▍ "); /// assert_eq!(unicode_block_bar(13, 0.9).to_string(), "███████████▋ "); /// assert_eq!(unicode_block_bar(13, 1.0).to_string(), "█████████████"); /// # assert_eq!(unicode_block_bar(4, 0.0).to_string(), " "); /// # assert_eq!(unicode_block_bar(4, 0.125).to_string(), "▌ "); /// # assert_eq!(unicode_block_bar(4, 0.25).to_string(), "█ "); /// # assert_eq!(unicode_block_bar(4, 1.0).to_string(), "████"); /// # assert_eq!(unicode_block_bar(4, 1.5).to_string(), "████"); /// # assert_eq!(unicode_block_bar(4, -1.0).to_string(), " "); /// # assert_eq!(unicode_block_bar(1, 1.0).to_string(), "█"); /// # assert_eq!(unicode_block_bar(0, 0.0).to_string(), ""); /// # assert_eq!(unicode_block_bar(0, 1.0).to_string(), ""); /// ``` pub fn unicode_block_bar(max_length: usize, proportion: f32) -> impl core::fmt::Display { // index x = x 8ths of a full block const BLOCK_CHARS: [&str; 9] = [" ", "▏", "▎", "▍", "▌", "▋", "▊", "▉", "█"]; struct UnicodeBlockBar { num_full_blocks: usize, /// may be empty! midpoint: &'static str, num_spaces: usize, } impl core::fmt::Display for UnicodeBlockBar { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { for _ in 0..self.num_full_blocks { f.write_str(&BLOCK_CHARS[8])?; } f.write_str(self.midpoint)?; for _ in 0..self.num_spaces { f.write_str(&BLOCK_CHARS[0])?; } Ok(()) } } let max_steps = max_length * 8; // number of steps for the bar to be full let steps = proportion * max_steps as f32; let steps = (steps.max(0.0) as usize).min(max_steps); if steps == max_steps { UnicodeBlockBar { num_full_blocks: max_length, midpoint: "", num_spaces: 0, } } else { #[allow(clippy::indexing_slicing)] // index will be in 0..8 always due to modulo UnicodeBlockBar { num_full_blocks: steps / 8, midpoint: &BLOCK_CHARS[steps % 8], num_spaces: max_length - (steps / 8 + 1), } } } /// Print a sequence of equalizer-style vertical bars using Unicode block characters. /// /// The bars are very high-resolution: 8 states can be represented per character. /// /// Accepts the total maximum height of the bars and an iterator over each bar's fill percentage. /// /// ```rust /// let expected_output = "\ /// █ /// █▆ /// ██▄ /// ███▁ /// ████ /// ████▇ /// █████▄ /// ██████▂ /// ███████ /// ████████ /// ████████▅ /// █████████▃ /// ██████████ "; /// /// assert_eq!( /// display_utils::vertical_unicode_block_bars( /// 13, /// [1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.0].iter().copied() /// ).to_string(), /// expected_output, /// ); /// ``` pub fn vertical_unicode_block_bars<I>(max_height: usize, proportions: I) -> impl core::fmt::Display where I: IntoIterator<Item = f32>, I::IntoIter: Clone, { // index x = x 8ths of a full block const BLOCK_CHARS: [&str; 9] = [" ", "▁", "▂", "▃", "▄", "▅", "▆", "▇", "█"]; struct VerticalUnicodeBlockBars<I> { max_height: usize, proportions: I, } impl<I: Iterator<Item = f32> + Clone> core::fmt::Display for VerticalUnicodeBlockBars<I> { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { let max_steps = self.max_height * 8; for row in 0..self.max_height { if row > 0 { f.write_str("\n")?; } for proportion in self.proportions.clone() { // steps are measured in terms of whitespace let steps = (1.0 - proportion) * max_steps as f32; let steps = (steps.max(0.0) as usize).min(max_steps); f.write_str(match row.cmp(&(steps / 8)) { core::cmp::Ordering::Less => &BLOCK_CHARS[0], #[allow(clippy::indexing_slicing)] // that index will always be in 0..=8 core::cmp::Ordering::Equal => &BLOCK_CHARS[8 - steps % 8], core::cmp::Ordering::Greater => &BLOCK_CHARS[8], })?; } } Ok(()) } } VerticalUnicodeBlockBars { max_height, proportions: proportions.into_iter() } } /// Concatenate iterator elements, separating each element pair with a given joiner. /// /// Equivalent to [`slice::join`](https://doc.rust-lang.org/std/primitive.slice.html#method.join). /// /// The iterator must be cloneable, because Display objects may be printed multiple times. /// /// ```rust /// # use display_utils::*; /// let strings = &["hello", "wonderful", "world"]; /// /// let output = join(strings, ", "); /// assert_eq!(output.to_string(), "hello, wonderful, world"); /// # assert_eq!(join(&[] as &[u8], ", ").to_string(), ""); /// # assert_eq!(join(&["hello"], ", ").to_string(), "hello"); /// ``` pub fn join<T, I, J>(iterator: I, joiner: J) -> impl core::fmt::Display where T: core::fmt::Display, I: IntoIterator<Item = T>, I::IntoIter: Clone, J: core::fmt::Display, { struct Join<I, J> { iterator: I, joiner: J, } impl<T, I, J> core::fmt::Display for Join<I, J> where T: core::fmt::Display, I: Iterator<Item = T> + Clone, J: core::fmt::Display, { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { let mut iter = self.iterator.clone(); if let Some(first_item) = iter.next() { first_item.fmt(f)?; } for remaining_item in iter { self.joiner.fmt(f)?; remaining_item.fmt(f)?; } Ok(()) } } Join { iterator: iterator.into_iter(), joiner } } /// Concatenate iterator elements, separating each element pair with a given joiner, where each /// iterator element can be formatted using a callback. /// /// The callback must be Fn and the iterator must be cloneable, because Display objects may be /// printed multiple times. /// /// ```rust /// # use display_utils::*; /// let strings = &["hello", "wonderful", "world"]; /// /// let output = join_format( /// strings.iter().enumerate(), /// |(i, string), f| write!(f, "{}={}", i, string), /// ", ", /// ); /// assert_eq!(output.to_string(), "0=hello, 1=wonderful, 2=world"); /// ``` pub fn join_format<I, C, J>(iterator: I, callback: C, joiner: J) -> impl core::fmt::Display where I: IntoIterator, I::IntoIter: Clone, C: Fn(I::Item, &mut core::fmt::Formatter) -> core::fmt::Result, J: core::fmt::Display, { struct Join<I, C, J> { iterator: I, callback: C, joiner: J, } impl<I, C, J> core::fmt::Display for Join<I, C, J> where I: Iterator + Clone, C: Fn(I::Item, &mut core::fmt::Formatter) -> core::fmt::Result, J: core::fmt::Display, { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { let mut iter = self.iterator.clone(); if let Some(first_item) = iter.next() { (self.callback)(first_item, f)?; } for remaining_item in iter { self.joiner.fmt(f)?; (self.callback)(remaining_item, f)?; } Ok(()) } } Join { iterator: iterator.into_iter(), callback, joiner } } /// Repeat an object a certain number of times. /// /// Equivalent to `str::repeat`. /// /// ```rust /// # use display_utils::*; /// assert_eq!(repeat("fun", 5).to_string(), "funfunfunfunfun"); /// assert_eq!(repeat(7, 7).to_string(), "7777777"); /// # assert_eq!(repeat("a", 0).to_string(), ""); /// # assert_eq!(repeat("", 5).to_string(), ""); /// ``` pub fn repeat<T: core::fmt::Display>(token: T, times: usize) -> impl core::fmt::Display { struct Repeat<T> { token: T, times: usize, } impl<T: core::fmt::Display> core::fmt::Display for Repeat<T> { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { for _ in 0..self.times { write!(f, "{}", self.token)?; } Ok(()) } } Repeat { token, times } } /// Indent to a given depth using the tab character. /// /// This is a shortcut for `repeat("\t", depth)`; please see that function if you wish to use a /// different indent string. /// /// ```rust /// # use display_utils::*; /// assert_eq!(indent(2).to_string(), "\t\t"); /// # assert_eq!(indent(0).to_string(), ""); /// # assert_eq!(indent(1).to_string(), "\t"); /// ``` pub fn indent_tab(depth: usize) -> impl core::fmt::Display { repeat("\t", depth) } /// Indent to a given depth using 4 spaces. /// /// This is a shortcut for `repeat(" ", depth)`; please see that function if you wish to use a /// different indent string. /// /// ```rust /// # use display_utils::*; /// assert_eq!(indent(2).to_string(), " "); /// # assert_eq!(indent(0).to_string(), ""); /// # assert_eq!(indent(1).to_string(), " "); /// ``` pub fn indent_4(depth: usize) -> impl core::fmt::Display { repeat(" ", depth) } /// Print a Unicode-compliant lowercase version of the string. /// /// Equivalent to `str::to_lowercase`. /// /// ```rust /// # use display_utils::*; /// assert_eq!(lowercase("GRÜẞE JÜRGEN").to_string(), "grüße jürgen"); /// ``` pub fn lowercase(source: &str) -> impl core::fmt::Display + '_ { struct AsciiLowercase<'a> { source: &'a str, } impl<'a> core::fmt::Display for AsciiLowercase<'a> { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { use core::fmt::Write; for input_char in self.source.chars() { for output_char in input_char.to_lowercase() { f.write_char(output_char)?; } } Ok(()) } } AsciiLowercase { source } } /// Print a Unicode-compliant uppercase version of the string. /// /// Equivalent to `str::to_uppercase`. /// /// ```rust /// # use display_utils::*; /// assert_eq!(uppercase("grüße jürgen").to_string(), "GRÜSSE JÜRGEN"); /// ``` pub fn uppercase(source: &str) -> impl core::fmt::Display + '_ { struct AsciiUppercase<'a> { source: &'a str, } impl<'a> core::fmt::Display for AsciiUppercase<'a> { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { use core::fmt::Write; for input_char in self.source.chars() { for output_char in input_char.to_uppercase() { f.write_char(output_char)?; } } Ok(()) } } AsciiUppercase { source } } /// Replace instances of the `from` string with the `to` string. /// /// Note: this function, contrary to its std equivalent /// [`str::replace`](https://doc.rust-lang.org/std/primitive.str.html#method.replace), /// does not support the Pattern API because that API is not yet stabilized. /// /// ```rust /// # use display_utils::*; /// assert_eq!(replace("this is old", "old", "new").to_string(), "this is new"); /// # assert_eq!(replace("", "aaaaa", "xinbuldfgh").to_string(), ""); /// # assert_eq!(replace("old is this", "old", "new").to_string(), "new is this"); /// ``` // TODO: change `from` parameter type to Pattern, once that API is stabilized pub fn replace<'a>(source: &'a str, from: &'a str, to: &'a str) -> impl core::fmt::Display + 'a { struct Replace<'a> { source: &'a str, from: &'a str, to: &'a str, } impl<'a> core::fmt::Display for Replace<'a> { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { let mut last_end = 0; for (start, part) in self.source.match_indices(self.from) { // UNWRAP: match_indices returns well-aligned indices f.write_str(self.source.get(last_end..start).unwrap())?; f.write_str(self.to)?; last_end = start + part.len(); } // UNWRAP: last_end is well-aligned still f.write_str(self.source.get(last_end..).unwrap())?; Ok(()) } } Replace { source, from, to } } /// Replace the first n instances of the `from` string with the `to` string. /// /// Note: this function, contrary to its std equivalent /// [`str::replacen`](https://doc.rust-lang.org/std/primitive.str.html#method.replacen), /// does not support the Pattern API because that API is not yet stabilized. /// /// ```rust /// # use display_utils::*; /// assert_eq!(replace_n("old old old", "old", "new", 2).to_string(), "new new old"); /// # assert_eq!(replace_n("", "aaaaa", "xinbuldfgh", 987).to_string(), ""); /// # assert_eq!(replace_n("old is this", "old", "new", 0).to_string(), "old is this"); /// ``` // TODO: change `from` parameter type to Pattern, once that API is stabilized pub fn replace_n<'a>( source: &'a str, from: &'a str, to: &'a str, n: usize ) -> impl core::fmt::Display + 'a { struct ReplaceN<'a> { source: &'a str, from: &'a str, to: &'a str, n: usize, } impl<'a> core::fmt::Display for ReplaceN<'a> { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { let mut last_end = 0; for (start, part) in self.source.match_indices(self.from).take(self.n) { // UNWRAP: match_indices returns well-aligned indices f.write_str(self.source.get(last_end..start).unwrap())?; f.write_str(self.to)?; last_end = start + part.len(); } // UNWRAP: last_end is well-aligned still f.write_str(self.source.get(last_end..).unwrap())?; Ok(()) } } ReplaceN { source, from, to, n } } /// Concatenate the contents of an iterator. /// /// If you want to insert a separator inbetween elements, use [`join`] or [`join_format`]. /// /// ```rust /// # use display_utils::*; /// let string = String::from("It's not much, but it's honest work"); /// assert_eq!(concat(&[ /// &string[11..13], /// &string[25..27], /// &string[34..35], /// ]).to_string(), "chonk"); /// # assert_eq!(concat(&[1, 2, 3]).to_string(), "123"); /// # assert_eq!(concat(None::<u8>).to_string(), ""); /// ``` pub fn concat<I>(iterator: I) -> impl core::fmt::Display where I: IntoIterator, I::Item: core::fmt::Display, I::IntoIter: Clone, { struct Concat<I> { iterator: I, } impl<I> core::fmt::Display for Concat<I> where I: Iterator + Clone, I::Item: core::fmt::Display, { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { for item in self.iterator.clone() { write!(f, "{}", item)?; } Ok(()) } } Concat { iterator: iterator.into_iter() } }