1157 lines
44 KiB
Rust
1157 lines
44 KiB
Rust
extern crate unicode_segmentation;
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use self::unicode_segmentation::UnicodeSegmentation;
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use crate::grapheme_clusters::TextProcessing;
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use crate::tables::LINE_BREAK_RULES;
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use crate::types::LineBreakClass;
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use crate::types::Reflow;
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use core::cmp::Ordering;
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use core::iter::Peekable;
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use core::str::FromStr;
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use LineBreakClass::*;
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#[derive(Debug, PartialEq, Copy, Clone)]
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pub enum LineBreakCandidate {
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MandatoryBreak,
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BreakAllowed,
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NoBreak, // Not used.
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}
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impl Default for LineBreakCandidate {
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fn default() -> Self {
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LineBreakCandidate::NoBreak
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}
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}
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use LineBreakCandidate::*;
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pub struct LineBreakCandidateIter<'a> {
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text: &'a str,
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iter: Peekable<unicode_segmentation::GraphemeIndices<'a>>,
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pos: usize,
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/* Needed for rule LB30a */
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reg_ind_streak: u32,
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}
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impl<'a> LineBreakCandidateIter<'a> {
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pub fn new(text: &'a str) -> Self {
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LineBreakCandidateIter {
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text,
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pos: 0,
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iter: UnicodeSegmentation::grapheme_indices(text, true).peekable(),
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reg_ind_streak: 0,
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}
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}
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}
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macro_rules! get_base_character {
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($grapheme:ident) => {{
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char::from_str($grapheme.get(0..1).unwrap_or_else(|| {
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$grapheme.get(0..2).unwrap_or_else(|| {
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$grapheme
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.get(0..3)
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.unwrap_or_else(|| $grapheme.get(0..4).unwrap())
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})
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}))
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}};
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($grapheme:expr) => {{
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char::from_str($grapheme.get(0..1).unwrap_or_else(|| {
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$grapheme.get(0..2).unwrap_or_else(|| {
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$grapheme
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.get(0..3)
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.unwrap_or_else(|| $grapheme.get(0..4).unwrap())
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})
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}))
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}};
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}
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/// Side effects: none
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macro_rules! get_class {
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($grapheme:ident) => {{
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get_base_character!($grapheme)
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.map(|char| search_table(char as u32, LINE_BREAK_RULES))
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.unwrap_or(XX)
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}};
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($grapheme:expr) => {{
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get_base_character!($grapheme)
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.map(|char| search_table(char as u32, LINE_BREAK_RULES))
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.unwrap_or(XX)
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}};
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}
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/// Side effects: Updates $graph_iter and potentially $idx and $grapheme
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macro_rules! next_grapheme_class {
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($graph_iter:ident, $grapheme:ident) => ({
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if let Some((_, g)) = $graph_iter.next() {
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$grapheme = g;
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Some(get_class!(g))
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} else { None }
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});
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(($next_char:ident is $class:expr)) => ({
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$next_char.is_some() && get_class!(($next_char.unwrap().1)) == $class
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});
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(($next_char:ident is $($class:ident),+)) => ({
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$next_char.is_some() && ($(get_class!(($next_char.unwrap().1)) == $class)||+)
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});
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}
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/// Returns positions where breaks can happen
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/// Examples:
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/// ```
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/// use text_processing::{self, LineBreakCandidate::{self, *}};
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/// use text_processing::line_break::LineBreakCandidateIter;
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///
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/// assert!(LineBreakCandidateIter::new("").collect::<Vec<(usize, LineBreakCandidate)>>().is_empty());
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/// assert_eq!(&[(7, BreakAllowed), (12, MandatoryBreak)],
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/// LineBreakCandidateIter::new("Sample Text.").collect::<Vec<(usize, LineBreakCandidate)>>().as_slice());
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/// assert_eq!(&[(3, MandatoryBreak), (7, MandatoryBreak), (10, BreakAllowed), (17, MandatoryBreak)],
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/// LineBreakCandidateIter::new("Sa\nmp\r\nle T(e)xt.").collect::<Vec<(usize, LineBreakCandidate)>>().as_slice());
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/// ```
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impl<'a> Iterator for LineBreakCandidateIter<'a> {
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type Item = (usize, LineBreakCandidate);
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fn next(&mut self) -> Option<Self::Item> {
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// After end of text, there are no breaks.
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if self.pos >= self.text.len() {
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return None;
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}
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// LB3 Always break at the end of text
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if self.pos + 1 == self.text.len() {
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self.pos += 1;
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return Some((self.pos, MandatoryBreak));
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}
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let (idx, mut grapheme) = self.iter.next().unwrap();
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let LineBreakCandidateIter {
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ref mut iter,
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ref text,
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ref mut reg_ind_streak,
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ref mut pos,
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} = self;
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let iter = iter.by_ref();
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debug_assert_eq!(idx, *pos);
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// LB2 Never break at the start of text
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if idx == 0 {
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*pos += grapheme.len();
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return self.next();
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}
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let class = get_class!(grapheme);
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if class != RI {
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*reg_ind_streak = 0;
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}
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/* LB1 Assign a line breaking class to each code point of the input. Resolve AI, CB, CJ,
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* SA, SG, and XX into other line breaking classes depending on criteria outside the scope
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* of this algorithm.
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*
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* In the absence of such criteria all characters with a specific combination of original
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* class and General_Category property value are resolved as follows:
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* Resolved Original General_Category
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* AL AI, SG, XX Any
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* CM SA Only Mn or Mc
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* AL SA Any except Mn and Mc
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* NS SJ Any
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*/
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// TODO: LB1
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/* Check if next character class allows breaks before it */
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let next_char: Option<&(usize, &str)> = iter.peek();
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match class {
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BK => {
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// LB4 Always Break after hard line breaks.
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*pos += grapheme.len();
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return Some((*pos, MandatoryBreak));
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}
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// LB5 Treat CR followed by LF, as well as CR, LF, and NL as hard line breaks
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CR if next_grapheme_class!((next_char is LF)) => {
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*pos += grapheme.len();
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assert!(Some(LF) == next_grapheme_class!(iter, grapheme));
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*pos += grapheme.len();
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return Some((*pos, MandatoryBreak));
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}
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CR | LF | NL => {
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*pos += grapheme.len();
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return Some((*pos, MandatoryBreak));
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}
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_ => {}
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}
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if let Some((_, next_grapheme)) = next_char {
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let next_class = get_class!(next_grapheme);
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match next_class {
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/* LB6 Do not break before hard line breaks. × ( BK | CR | LF | NL ) */
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BK | CR | LF | NL => {
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*pos += grapheme.len();
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return self.next();
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}
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/* LB7 Do not break before spaces or zero width
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* space. × SP × ZW */
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SP | ZW => {
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*pos += grapheme.len();
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return self.next();
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}
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_ => {}
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}
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}
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match class {
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ZW => {
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// LB8 Break before any character following a zero-width space, even if one or more
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// spaces intervene
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// ZW SP* ÷
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*pos += grapheme.len();
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while Some(SP) == next_grapheme_class!(iter, grapheme) {
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*pos += grapheme.len();
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}
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return Some((*pos, MandatoryBreak));
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}
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ZWJ => {
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// LB8a Do not break after a zero width joiner.
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*pos += grapheme.len();
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return self.next();
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}
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CM => {
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// LB9 Do not break a combining character sequence; treat it as if it has the line
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// breaking class of the base character in all of the following rules. Treat ZWJ as
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// if it were CM.
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// Treat X (CM | ZWJ)* as if it were X.
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// where X is any line break class except BK, CR, LF, NL, SP, or ZW.
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/* Unreachable since we break lines based on graphemes, not characters */
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unreachable!();
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}
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WJ => {
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/*: LB11 Do not break before or after Word joiner and related characters.*/
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*pos += grapheme.len();
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/* Get next grapheme */
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if next_grapheme_class!(iter, grapheme).is_some() {
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*pos += grapheme.len();
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}
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return self.next();
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}
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GL => {
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/*LB12 Non-breaking characters: LB12 Do not break after NBSP and related characters.*/
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*pos += grapheme.len();
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return self.next();
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}
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_ => {}
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}
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if let Some((next_idx, next_grapheme)) = next_char {
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let next_class = get_class!(next_grapheme);
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match next_class {
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GL if ![SP, BA, HY].contains(&class) => {
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/* LB12a Do not break before NBSP and related characters, except after spaces and
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* hyphens. [^SP BA HY] × GL
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* Also LB12 Do not break after NBSP and related characters */
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*pos += grapheme.len();
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return self.next();
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}
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/* LB13 Do not break before ‘]’ or ‘!’ or ‘;’ or ‘/’, even after spaces. */
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CL | CP | EX | IS | SY => {
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*pos = *next_idx;
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return self.next();
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}
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_ => {}
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}
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}
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match class {
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/* LB13 Do not break before ‘]’ or ‘!’ or ‘;’ or ‘/’, even after spaces. */
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SP if [CL, CP, EX, IS, SY].contains(&get_class!(text[idx..].trim_start())) => {
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*pos += grapheme.len();
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while ![CL, CP, EX, IS, SY].contains(&next_grapheme_class!(iter, grapheme).unwrap())
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{
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*pos += grapheme.len();
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}
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*pos += grapheme.len();
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return self.next();
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}
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OP => {
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/* LB14 Do not break after ‘[’, even after spaces.
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* OP SP* ×
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*/
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while let Some((idx, grapheme)) = self.iter.next() {
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*pos = idx + grapheme.len();
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if !(get_class!(grapheme) == SP) {
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break;
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}
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}
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return self.next();
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}
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QU if get_class!(text[idx..].trim_start()) == OP => {
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/* LB15 Do not break within ‘”[’, even with intervening spaces.
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* QU SP* × OP */
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*pos += grapheme.len();
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while Some(SP) == next_grapheme_class!(iter, grapheme) {
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*pos += grapheme.len();
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}
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*pos = idx;
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return self.next();
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}
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QU => {
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/* LB19 Do not break before or after quotation marks, such as ‘ ” ’. */
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*pos += grapheme.len();
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if let Some((_, g)) = self.iter.next() {
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*pos += g.len();
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}
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return self.next();
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}
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LineBreakClass::CL | LineBreakClass::CP
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if get_class!(text[idx..].trim_start()) == NS =>
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{
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/* LB16 Do not break between closing punctuation and a nonstarter (lb=NS), even with
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* intervening spaces.
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* (CL | CP) SP* × NS */
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*pos += grapheme.len();
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while Some(SP) == next_grapheme_class!(iter, grapheme) {
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*pos += grapheme.len();
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}
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return self.next();
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}
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B2 if get_class!(text[idx..].trim_start()) == B2 => {
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*pos += grapheme.len();
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while Some(SP) == next_grapheme_class!(iter, grapheme) {
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*pos += grapheme.len();
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}
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return self.next();
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}
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SP => {
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/* LB18 Break after spaces. SP ÷ */
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// Space 0x20 is 1 byte long.
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*pos += 1;
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return Some((*pos, BreakAllowed));
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}
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_ => {}
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}
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if let Some((next_idx, next_grapheme)) = next_char {
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let next_class = get_class!(next_grapheme);
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match next_class {
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QU if class != SP => {
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/* LB19 Do not break before or after quotation marks, such as ‘ ” ’. */
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*pos = *next_idx + next_grapheme.len();
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self.iter.next();
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return self.next();
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}
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_ => {}
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}
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}
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match class {
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CB => {
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/* LB20 Break before and after unresolved CB. */
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*pos += grapheme.len();
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return Some((*pos - 1, BreakAllowed));
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}
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/* LB21 Do not break before hyphen-minus, other hyphens, fixed-width spaces, small
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* kana, and other non-starters, or after acute accents. × BA, × HY, × NS, BB × */
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BB => {
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*pos += grapheme.len();
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return self.next();
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}
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_ => {}
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}
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if let Some((_, next_grapheme)) = next_char {
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let next_class = get_class!(next_grapheme);
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match next_class {
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BA | HY | NS => {
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/* LB21 Do not break before hyphen-minus, other hyphens, fixed-width spaces, small
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* kana, and other non-starters, or after acute accents. × BA, × HY, × NS, BB × */
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*pos += grapheme.len();
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return self.next();
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}
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_ => {}
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}
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}
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match class {
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HL if next_grapheme_class!((next_char is HY, BA)) => {
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/* LB21a Don’t break after Hebrew + Hyphen. HL (HY | BA) × */
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let (idx, next_grapheme) = next_char.unwrap();
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*pos = idx + next_grapheme.len();
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self.iter.next();
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return self.next();
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}
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/* LB21b Don’t break between ,Solidus and Hebrew letters. SY × HL */
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SY if next_grapheme_class!((next_char is HL)) => {
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let (idx, next_grapheme) = next_char.unwrap();
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*pos = idx + next_grapheme.len();
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/* bypass next_char */
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self.iter.next().unwrap();
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if let Some((idx, next_grapheme)) = self.iter.next() {
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*pos = idx + next_grapheme.len();
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}
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return self.next();
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}
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/* LB22 Do not break between two ellipses, or between letters, numbers or excla-
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* mations and ellipsis.
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* Examples: ‘9...’, ‘a...’, ‘H...’
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* (AL | HL) × IN */
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AL | HL if next_grapheme_class!((next_char is IN)) => {
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let (idx, next_grapheme) = next_char.unwrap();
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*pos = idx + next_grapheme.len();
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self.iter.next();
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return self.next();
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}
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/* EX × IN */
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EX if next_grapheme_class!((next_char is IN)) => {
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let (idx, next_grapheme) = next_char.unwrap();
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*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
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return self.next();
|
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}
|
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EX => {
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// LB13
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*pos += grapheme.len();
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return self.next();
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}
|
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/* (ID | EB | EM) × IN */
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ID | EB | EM if next_grapheme_class!((next_char is IN)) => {
|
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let (idx, next_grapheme) = next_char.unwrap();
|
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*pos = idx + next_grapheme.len();
|
||
self.iter.next();
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return self.next();
|
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}
|
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/* IN × IN */
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IN if next_grapheme_class!((next_char is IN)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
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/* NU × IN */
|
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NU if next_grapheme_class!((next_char is IN)) => {
|
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let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* LB23 Do not break between digits and letters.
|
||
* (AL | HL) × NU */
|
||
AL | HL if next_grapheme_class!((next_char is NU)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
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/* NU × (AL | HL) */
|
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NU if next_grapheme_class!((next_char is AL, HL)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* LB23a Do not break between numeric prefixes and ideographs, or between ideographs
|
||
* and numeric postfixes.
|
||
* PR × (ID | EB | EM) */
|
||
PR if next_grapheme_class!((next_char is ID, EB, EM)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* (ID | EB | EM) × PO */
|
||
ID | EB | EM if next_grapheme_class!((next_char is PO)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* B24 Do not break between numeric prefix/postfix and letters, or between
|
||
letters and prefix/postfix.
|
||
(PR | PO) × (AL | HL)*/
|
||
PR | PO if next_grapheme_class!((next_char is AL, HL)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/*(AL | HL) × (PR | PO) */
|
||
AL | HL if next_grapheme_class!((next_char is PR, PO)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* LB25 Do not break between the following pairs of classes relevant to numbers:
|
||
* CL × PO */
|
||
CL if next_grapheme_class!((next_char is PO)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* CP × PO */
|
||
CP if next_grapheme_class!((next_char is PO)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* CL × PR */
|
||
CL if next_grapheme_class!((next_char is PR)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* CP × PR */
|
||
CP if next_grapheme_class!((next_char is PR)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* NU × PO */
|
||
NU if next_grapheme_class!((next_char is PO)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* NU × PR */
|
||
NU if next_grapheme_class!((next_char is PR)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* PO × OP */
|
||
PO if next_grapheme_class!((next_char is OP)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* PO × NU */
|
||
PO if next_grapheme_class!((next_char is NU)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* PR × OP */
|
||
PR if next_grapheme_class!((next_char is OP)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* PR × NU */
|
||
PR if next_grapheme_class!((next_char is NU)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* HY × NU */
|
||
HY if next_grapheme_class!((next_char is NU)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* IS × NU */
|
||
IS if next_grapheme_class!((next_char is NU)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* NU × NU */
|
||
NU if next_grapheme_class!((next_char is NU)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* SY × NU */
|
||
SY if next_grapheme_class!((next_char is NU)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* LB26 Do not break a Korean syllable.
|
||
* JL × (JL | JV | H2 | H3) */
|
||
JL if next_grapheme_class!((next_char is JL, JV, H2, H3)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* (JV | H2) × (JV | JT) */
|
||
JV | H2 if next_grapheme_class!((next_char is JV, JT)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* (JT | H3) × JT */
|
||
JT | H3 if next_grapheme_class!((next_char is JT)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* LB27 Treat a Korean Syllable Block the same as ID.
|
||
* (JL | JV | JT | H2 | H3) × IN */
|
||
JL | JV | JT | H2 | H3 if next_grapheme_class!((next_char is IN)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* (JL | JV | JT | H2 | H3) × PO */
|
||
JL | JV | JT | H2 | H3 if next_grapheme_class!((next_char is PO)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* PR × (JL | JV | JT | H2 | H3) */
|
||
PR if next_grapheme_class!((next_char is JL, JV, JT, H2, H3)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* LB28 Do not break between alphabetics (“at”).
|
||
(AL | HL) × (AL | HL) */
|
||
AL | HL if next_grapheme_class!((next_char is AL, HL)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* LB29 Do not break between numeric punctuation and alphabetics (“e.g.”).
|
||
IS × (AL | HL) */
|
||
IS if next_grapheme_class!((next_char is AL, HL)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* LB30 Do not break between letters, numbers, or ordinary symbols and opening
|
||
or closing parentheses.
|
||
(AL | HL | NU) × OP */
|
||
AL | HL | NU if next_grapheme_class!((next_char is OP)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/* CP × (AL | HL | NU) */
|
||
CP if next_grapheme_class!((next_char is AL, HL , NU)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
/*LB30b Do not break between an emoji base and an emoji modifier.
|
||
* EB × EM */
|
||
EB if next_grapheme_class!((next_char is EM)) => {
|
||
let (idx, next_grapheme) = next_char.unwrap();
|
||
*pos = idx + next_grapheme.len();
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
RI => {
|
||
/* LB30a Break between two regional indicator symbols if and only if there are an
|
||
* even number of regional indicators preceding the position of the break.
|
||
* sot (RI RI)* RI × RI
|
||
* [^RI] (RI RI)* RI × RI */
|
||
*reg_ind_streak += 1;
|
||
*pos += grapheme.len();
|
||
if *reg_ind_streak % 2 == 1 {
|
||
return Some((*pos - grapheme.len(), BreakAllowed));
|
||
}
|
||
self.iter.next();
|
||
return self.next();
|
||
}
|
||
_ => {
|
||
*pos += grapheme.len();
|
||
return Some((*pos - grapheme.len(), BreakAllowed));
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
fn search_table(c: u32, t: &'static [(u32, u32, LineBreakClass)]) -> LineBreakClass {
|
||
match t.binary_search_by(|&(lo, hi, _)| {
|
||
if lo <= c && c <= hi {
|
||
Ordering::Equal
|
||
} else if hi < c {
|
||
Ordering::Less
|
||
} else {
|
||
Ordering::Greater
|
||
}
|
||
}) {
|
||
Ok(idx) => t[idx].2,
|
||
Err(_) => XX,
|
||
}
|
||
}
|
||
|
||
#[cfg(test)]
|
||
mod tests {
|
||
use super::*;
|
||
|
||
#[test]
|
||
fn test_line_breaks() {
|
||
let s = "Fell past it.\n\n‘Well!’ thought Alice to herself.";
|
||
let breaks = LineBreakCandidateIter::new(s).collect::<Vec<(usize, LineBreakCandidate)>>();
|
||
let mut prev = 0;
|
||
for b in breaks {
|
||
println!("{:?}", &s[prev..b.0]);
|
||
prev = b.0;
|
||
}
|
||
println!("{:?}", &s[prev..]);
|
||
|
||
let s = r#"Τ' άστρα τα κοντά -στη γλυκιά σελήνη
|
||
την ειδή των κρύβουν - τη διαμαντένια,
|
||
άμα φως λαμπρό -στη γή πάσα χύνει,
|
||
όλη ασημένια."#;
|
||
let breaks = LineBreakCandidateIter::new(s).collect::<Vec<(usize, LineBreakCandidate)>>();
|
||
let mut prev = 0;
|
||
for b in breaks {
|
||
println!("{:?}", &s[prev..b.0]);
|
||
prev = b.0;
|
||
}
|
||
println!("{:?}", &s[prev..]);
|
||
}
|
||
}
|
||
|
||
pub use alg::linear;
|
||
|
||
mod alg {
|
||
use super::*;
|
||
use crate::grapheme_clusters::TextProcessing;
|
||
fn cost(i: usize, j: usize, width: usize, minima: &Vec<usize>, offsets: &Vec<usize>) -> usize {
|
||
let w = offsets[j] + j - offsets[i] - i - 1;
|
||
if w > width {
|
||
return 65536 * (w - width);
|
||
}
|
||
minima[i] + (width - w) * (width - w)
|
||
}
|
||
|
||
fn smawk(
|
||
rows: &mut Vec<usize>,
|
||
columns: &mut Vec<usize>,
|
||
minima: &mut Vec<usize>,
|
||
breaks: &mut Vec<usize>,
|
||
width: usize,
|
||
offsets: &Vec<usize>,
|
||
) {
|
||
let mut stack = Vec::new();
|
||
let mut i = 0;
|
||
while i < rows.len() {
|
||
if stack.len() > 0 {
|
||
let c = columns[stack.len() - 1];
|
||
if cost(*stack.iter().last().unwrap(), c, width, minima, offsets)
|
||
< cost(rows[i], c, width, minima, offsets)
|
||
{
|
||
if stack.len() < columns.len() {
|
||
stack.push(rows[i]);
|
||
}
|
||
i += 1;
|
||
} else {
|
||
stack.pop();
|
||
}
|
||
} else {
|
||
stack.push(rows[i]);
|
||
i += 1;
|
||
}
|
||
}
|
||
let rows = &mut stack;
|
||
if columns.len() > 1 {
|
||
let mut odd_columns = columns.iter().skip(1).step_by(2).cloned().collect();
|
||
smawk(rows, &mut odd_columns, minima, breaks, width, offsets);
|
||
for (i, o) in odd_columns.into_iter().enumerate() {
|
||
columns[2 * i + 1] = o;
|
||
}
|
||
}
|
||
let mut i = 0;
|
||
let mut j = 0;
|
||
while j < columns.len() {
|
||
let end = if j + 1 < columns.len() {
|
||
breaks[columns[j + 1]]
|
||
} else {
|
||
*rows.iter().last().unwrap()
|
||
};
|
||
let c = cost(rows[i], columns[j], width, minima, offsets);
|
||
if c < minima[columns[j]] {
|
||
minima[columns[j]] = c;
|
||
breaks[columns[j]] = rows[i];
|
||
}
|
||
if rows[i] < end {
|
||
i += 1;
|
||
} else {
|
||
j += 2;
|
||
}
|
||
}
|
||
}
|
||
|
||
pub fn linear(text: &str, width: usize) -> Vec<String> {
|
||
let mut words = Vec::new();
|
||
let breaks =
|
||
LineBreakCandidateIter::new(text).collect::<Vec<(usize, LineBreakCandidate)>>();
|
||
{
|
||
let mut prev = 0;
|
||
for b in breaks {
|
||
if text[prev..b.0].ends_with("\n") && text[b.0..].starts_with("\n") {
|
||
words.push(text[prev..b.0].trim_end_matches("\n"));
|
||
words.push("\n\n");
|
||
} else if &text[prev..b.0] != "\n" {
|
||
words.push(text[prev..b.0].trim_end_matches("\n"));
|
||
if text[prev..b.0].ends_with("\n") {
|
||
words.push(" ");
|
||
}
|
||
}
|
||
prev = b.0;
|
||
}
|
||
if &text[prev..] != "\n" {
|
||
words.push(text[prev..].trim_end_matches("\n"));
|
||
}
|
||
}
|
||
let count = words.len();
|
||
let mut minima = vec![std::usize::MAX - 1; count + 1];
|
||
minima[0] = 0;
|
||
let mut offsets = Vec::with_capacity(words.len());
|
||
offsets.push(0);
|
||
for w in words.iter() {
|
||
if *w == "\n\n" {
|
||
offsets.push(offsets.iter().last().unwrap() + width - 1);
|
||
} else {
|
||
offsets.push(offsets.iter().last().unwrap() + w.grapheme_len().saturating_sub(1));
|
||
}
|
||
}
|
||
|
||
let mut breaks = vec![0; count + 1];
|
||
|
||
let mut n = count + 1;
|
||
let mut i = 1;
|
||
let mut offset = 0;
|
||
loop {
|
||
let r = std::cmp::min(n, 2 * i);
|
||
let edge = i + offset;
|
||
smawk(
|
||
&mut (offset..edge).collect(),
|
||
&mut (edge..(r + offset)).collect(),
|
||
&mut minima,
|
||
&mut breaks,
|
||
width,
|
||
&offsets,
|
||
);
|
||
let x = minima[r - 1 + offset];
|
||
let mut for_was_broken = false;
|
||
for j in i..(r - 1) {
|
||
let y = cost(j + offset, r - 1 + offset, width, &minima, &offsets);
|
||
if y <= x {
|
||
n -= j;
|
||
i = 1;
|
||
offset += j;
|
||
for_was_broken = true;
|
||
break;
|
||
}
|
||
}
|
||
|
||
if !for_was_broken {
|
||
if r == n {
|
||
break;
|
||
}
|
||
i *= 2;
|
||
}
|
||
}
|
||
let paragraphs = text.split("\n\n").count();
|
||
let mut lines = Vec::new();
|
||
let mut j = count;
|
||
let mut p_i = 0;
|
||
while j > 0 {
|
||
let mut line = String::new();
|
||
for i in breaks[j]..j {
|
||
line.push_str(words[i]);
|
||
}
|
||
lines.push(line);
|
||
if p_i + 1 < paragraphs {
|
||
lines.push(String::new());
|
||
p_i += 1;
|
||
}
|
||
j = breaks[j];
|
||
}
|
||
lines.reverse();
|
||
lines
|
||
}
|
||
}
|
||
|
||
pub fn split_lines_reflow(text: &str, reflow: Reflow, width: Option<usize>) -> Vec<String> {
|
||
match reflow {
|
||
Reflow::FormatFlowed => {
|
||
/* rfc3676 - The Text/Plain Format and DelSp Parameters
|
||
* https://tools.ietf.org/html/rfc3676 */
|
||
|
||
let mut ret = Vec::new();
|
||
/*
|
||
* - Split lines with indices using str::match_indices()
|
||
* - Iterate and reflow flow regions, and pass fixed regions through
|
||
*/
|
||
let lines_indices: Vec<usize> = text.match_indices("\n").map(|(i, _)| i).collect();
|
||
let mut prev_index = 0;
|
||
let mut in_paragraph = false;
|
||
let mut paragraph_start = 0;
|
||
|
||
let mut prev_quote_depth = 0;
|
||
for i in &lines_indices {
|
||
let line = &text[prev_index..*i];
|
||
let mut trimmed = line.trim_start().lines().next().unwrap_or("");
|
||
let mut quote_depth = 0;
|
||
let p_str: usize = trimmed
|
||
.as_bytes()
|
||
.iter()
|
||
.position(|&b| {
|
||
if b != b'>' {
|
||
/* position() is short-circuiting */
|
||
true
|
||
} else {
|
||
quote_depth += 1;
|
||
false
|
||
}
|
||
})
|
||
.unwrap_or(0);
|
||
trimmed = &trimmed[p_str..];
|
||
if trimmed.starts_with(" ") {
|
||
/* Remove space stuffing before checking for ending space character.
|
||
* [rfc3676#section-4.4] */
|
||
trimmed = &trimmed[1..];
|
||
}
|
||
|
||
if trimmed.ends_with(' ') {
|
||
if !in_paragraph {
|
||
in_paragraph = true;
|
||
paragraph_start = prev_index;
|
||
} else if prev_quote_depth == quote_depth {
|
||
/* This becomes part of the paragraph we're in */
|
||
} else {
|
||
/*Malformed line, different quote depths can't be in the same paragraph. */
|
||
let paragraph = &text[paragraph_start..prev_index];
|
||
reflow_helper(&mut ret, paragraph, prev_quote_depth, in_paragraph, width);
|
||
|
||
paragraph_start = prev_index;
|
||
}
|
||
} else {
|
||
if prev_quote_depth == quote_depth || !in_paragraph {
|
||
let paragraph = &text[paragraph_start..*i];
|
||
reflow_helper(&mut ret, paragraph, quote_depth, in_paragraph, width);
|
||
} else {
|
||
/*Malformed line, different quote depths can't be in the same paragraph. */
|
||
let paragraph = &text[paragraph_start..prev_index];
|
||
reflow_helper(&mut ret, paragraph, prev_quote_depth, in_paragraph, width);
|
||
let paragraph = &text[prev_index..*i];
|
||
reflow_helper(&mut ret, paragraph, quote_depth, false, width);
|
||
}
|
||
paragraph_start = *i;
|
||
in_paragraph = false;
|
||
}
|
||
prev_quote_depth = quote_depth;
|
||
prev_index = *i;
|
||
}
|
||
let paragraph = &text[paragraph_start..text.len()];
|
||
reflow_helper(&mut ret, paragraph, prev_quote_depth, in_paragraph, width);
|
||
ret
|
||
}
|
||
Reflow::All => {
|
||
if let Some(width) = width {
|
||
let mut ret = Vec::new();
|
||
let width = width.saturating_sub(2);
|
||
|
||
for line in text.lines() {
|
||
if line.grapheme_len() <= width {
|
||
ret.push(line.to_string());
|
||
continue;
|
||
}
|
||
|
||
let breaks = LineBreakCandidateIter::new(line)
|
||
.collect::<Vec<(usize, LineBreakCandidate)>>();
|
||
&breaks.iter().enumerate().collect::<Vec<_>>();
|
||
if breaks.len() < 2 {
|
||
split(&mut ret, line, width);
|
||
continue;
|
||
}
|
||
|
||
let mut prev = 0;
|
||
let mut prev_line_offset = 0;
|
||
while prev < breaks.len() {
|
||
let new_off = match breaks[prev..].binary_search_by(|(offset, _)| {
|
||
line[prev_line_offset..*offset].grapheme_len().cmp(&width)
|
||
}) {
|
||
Ok(v) => v,
|
||
Err(v) => v,
|
||
} + prev;
|
||
let end_offset = if new_off >= breaks.len() {
|
||
line.len()
|
||
} else {
|
||
breaks[new_off].0
|
||
};
|
||
if !line[prev_line_offset..end_offset].is_empty() {
|
||
if prev_line_offset == 0 {
|
||
ret.push(format!("{}", &line[prev_line_offset..end_offset]));
|
||
} else {
|
||
ret.push(format!("⤷{}", &line[prev_line_offset..end_offset]));
|
||
}
|
||
}
|
||
prev_line_offset = end_offset;
|
||
prev = new_off;
|
||
}
|
||
}
|
||
ret
|
||
} else {
|
||
text.trim().split('\n').map(str::to_string).collect()
|
||
}
|
||
}
|
||
Reflow::No => text.trim().split('\n').map(str::to_string).collect(),
|
||
}
|
||
}
|
||
|
||
fn split(ret: &mut Vec<String>, mut line: &str, width: usize) {
|
||
while !line.is_empty() {
|
||
let mut chop_index = std::cmp::min(line.len().saturating_sub(1), width);
|
||
while chop_index > 0 && !line.is_char_boundary(chop_index) {
|
||
chop_index = chop_index - 1;
|
||
}
|
||
if chop_index == 0 {
|
||
ret.push(format!("⤷{}", line));
|
||
return;
|
||
} else {
|
||
ret.push(format!("⤷{}", &line[..chop_index]));
|
||
}
|
||
line = &line[chop_index..];
|
||
}
|
||
}
|
||
fn reflow_helper(
|
||
ret: &mut Vec<String>,
|
||
paragraph: &str,
|
||
quote_depth: usize,
|
||
in_paragraph: bool,
|
||
width: Option<usize>,
|
||
) {
|
||
if quote_depth > 0 {
|
||
let quotes: String = ">".repeat(quote_depth);
|
||
let paragraph = paragraph
|
||
.trim_start_matches("es)
|
||
.replace(&format!("\n{}", "es), "")
|
||
.replace("\n", "")
|
||
.replace("\r", "");
|
||
if in_paragraph {
|
||
if let Some(width) = width {
|
||
ret.extend(
|
||
linear(¶graph, width.saturating_sub(quote_depth))
|
||
.into_iter()
|
||
.map(|l| format!("{}{}", "es, l)),
|
||
);
|
||
} else {
|
||
ret.push(format!("{}{}", "es, ¶graph));
|
||
}
|
||
} else {
|
||
ret.push(format!("{}{}", "es, ¶graph));
|
||
}
|
||
} else {
|
||
let paragraph = paragraph.replace("\n", "").replace("\r", "");
|
||
|
||
if in_paragraph {
|
||
if let Some(width) = width {
|
||
let ex = linear(¶graph, width);
|
||
ret.extend(ex.into_iter());
|
||
} else {
|
||
ret.push(paragraph);
|
||
}
|
||
} else {
|
||
ret.push(paragraph);
|
||
}
|
||
}
|
||
}
|
||
|
||
#[test]
|
||
fn test_reflow() {
|
||
let text = r#"`Take some more tea,' the March Hare said to Alice, very
|
||
earnestly.
|
||
|
||
`I've had nothing yet,' Alice replied in an offended tone, `so
|
||
I can't take more.'
|
||
|
||
`You mean you can't take LESS,' said the Hatter: `it's very
|
||
easy to take MORE than nothing.'"#;
|
||
for l in split_lines_reflow(text, Reflow::FormatFlowed, Some(30)) {
|
||
println!("{}", l);
|
||
}
|
||
println!("");
|
||
for l in split_lines_reflow(text, Reflow::No, Some(30)) {
|
||
println!("{}", l);
|
||
}
|
||
println!("");
|
||
let text = r#">>>Take some more tea.
|
||
>>I've had nothing yet, so I can't take more.
|
||
>You mean you can't take LESS, it's very easy to take
|
||
>MORE than nothing."#;
|
||
for l in split_lines_reflow(text, Reflow::FormatFlowed, Some(20)) {
|
||
println!("{}", l);
|
||
}
|
||
println!("");
|
||
for l in split_lines_reflow(text, Reflow::No, Some(20)) {
|
||
println!("{}", l);
|
||
}
|
||
println!("");
|
||
let text = r#"CHAPTER I. Down the Rabbit-Hole
|
||
|
||
Alice was beginning to get very tired of sitting by her sister on the
|
||
bank, and of having nothing to do: once or twice she had peeped into the
|
||
book her sister was reading, but it had no pictures or conversations in
|
||
it, ‘and what is the use of a book,’ thought Alice ‘without pictures or
|
||
conversations?’
|
||
|
||
So she was considering in her own mind (as well as she could, for the
|
||
hot day made her feel very sleepy and stupid), whether the pleasure
|
||
of making a daisy-chain would be worth the trouble of getting up and
|
||
picking the daisies, when suddenly a White Rabbit with pink eyes ran
|
||
close by her.
|
||
|
||
>>There was nothing so VERY remarkable in that; nor did Alice think it so
|
||
>>VERY much out of the way to hear the Rabbit say to itself, ‘Oh dear!
|
||
>> Oh dear! I shall be late!’ (when she thought it over afterwards, it
|
||
>>occurred to her that she ought to have wondered at this, but at the time
|
||
>>it all seemed quite natural); but when the Rabbit actually TOOK A WATCH
|
||
OUT OF ITS WAISTCOAT-POCKET, and looked at it, and then hurried on,
|
||
>>Alice started to her feet, for it flashed across her mind that she had
|
||
>>never before seen a rabbit with either a waistcoat-pocket, or a watch
|
||
>>to take out of it, and burning with curiosity, she ran across the field
|
||
after it, and fortunately was just in time to see it pop down a large
|
||
rabbit-hole under the hedge.
|
||
|
||
In another moment down went Alice after it, never once considering how
|
||
in the world she was to get out again.
|
||
|
||
The rabbit-hole went straight on like a tunnel for some way, and then
|
||
dipped suddenly down, so suddenly that Alice had not a moment to think
|
||
about stopping herself before she found herself falling down a very deep
|
||
well.
|
||
|
||
Either the well was very deep, or she fell very slowly, for she had
|
||
plenty of time as she went down to look about her and to wonder what was
|
||
going to happen next. First, she tried to look down and make out what
|
||
she was coming to, but it was too dark to see anything; then she
|
||
looked at the sides of the well, and noticed that they were filled with
|
||
cupboards and book-shelves; here and there she saw maps and pictures
|
||
hung upon pegs. She took down a jar from one of the shelves as
|
||
she passed; it was labelled ‘ORANGE MARMALADE’, but to her great
|
||
disappointment it was empty: she did not like to drop the jar for fear
|
||
of killing somebody, so managed to put it into one of the cupboards as
|
||
she fell past it.
|
||
|
||
‘Well!’ thought Alice to herself, ‘after such a fall as this, I shall
|
||
think nothing of tumbling down stairs! How brave they’ll all think me at
|
||
home! Why, I wouldn’t say anything about it, even if I fell off the top
|
||
of the house!’ (Which was very likely true.)"#;
|
||
for l in split_lines_reflow(text, Reflow::FormatFlowed, Some(72)) {
|
||
println!("{}", l);
|
||
}
|
||
}
|