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text_processing: add reflow method() and enum to TextProcessing trait

Add
 split_lines_reflow(&self, reflow: Reflow, width: Option<usize>) -> Vec<String>
method that, according to reflow (No reflow, FormatFlowed
or All) reflows the text.

FormatFlowed follows the rfc3676 - The Text/Plain Format and DelSp Parameters
https://tools.ietf.org/html/rfc3676
jmap
Manos Pitsidianakis 2 years ago
parent
commit
b01b9ffbcb
Signed by: epilys GPG Key ID: 73627C2F690DF710
  1. 7
      text_processing/src/grapheme_clusters.rs
  2. 1
      text_processing/src/lib.rs
  3. 215
      text_processing/src/line_break.rs
  4. 13
      text_processing/src/types.rs

7
text_processing/src/grapheme_clusters.rs

@ -8,6 +8,7 @@
*/
use crate::types::Reflow;
use crate::wcwidth::{wcwidth, CodePointsIter};
extern crate unicode_segmentation;
use self::unicode_segmentation::UnicodeSegmentation;
@ -43,12 +44,18 @@ pub trait TextProcessing: UnicodeSegmentation + CodePointsIter {
}
fn split_lines(&self, width: usize) -> Vec<String>;
fn split_lines_reflow(&self, reflow: Reflow, width: Option<usize>) -> Vec<String>;
}
impl TextProcessing for str {
fn split_lines(&self, width: usize) -> Vec<String> {
crate::line_break::linear(self, width)
}
fn split_lines_reflow(&self, reflow: Reflow, width: Option<usize>) -> Vec<String> {
crate::line_break::split_lines_reflow(self, reflow, width)
}
}
pub struct WordBreakIter<'s> {

1
text_processing/src/lib.rs

@ -2,6 +2,7 @@ pub mod grapheme_clusters;
pub mod line_break;
mod tables;
mod types;
pub use types::Reflow;
pub mod wcwidth;
pub use grapheme_clusters::*;
pub use line_break::*;

215
text_processing/src/line_break.rs

@ -2,6 +2,7 @@ extern crate unicode_segmentation;
use self::unicode_segmentation::UnicodeSegmentation;
use crate::tables::LINE_BREAK_RULES;
use crate::types::LineBreakClass;
use crate::types::Reflow;
use core::cmp::Ordering;
use core::iter::Peekable;
use core::str::FromStr;
@ -875,3 +876,217 @@ mod alg {
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 {
linear(text, width)
} else {
text.trim().split('\n').map(str::to_string).collect()
}
}
Reflow::No => text.trim().split('\n').map(str::to_string).collect(),
}
}
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(&quotes)
.replace(&format!("\n{}", &quotes), "")
.replace("\n", "")
.replace("\r", "");
if in_paragraph {
if let Some(width) = width {
ret.extend(
linear(&paragraph, width.saturating_sub(quote_depth))
.into_iter()
.map(|l| format!("{}{}", &quotes, l)),
);
} else {
ret.push(format!("{}{}", &quotes, &paragraph));
}
} else {
ret.push(format!("{}{}", &quotes, &paragraph));
}
} else {
let paragraph = paragraph.replace("\n", "").replace("\r", "");
if in_paragraph {
if let Some(width) = width {
let ex = linear(&paragraph, 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, β€˜and what is the use of a book,’ thought Alice β€˜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, β€˜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 β€˜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.
β€˜Well!’ thought Alice to herself, β€˜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);
}
}

13
text_processing/src/types.rs

@ -100,3 +100,16 @@ impl From<&str> for LineBreakClass {
}
}
}
#[derive(PartialEq, Debug, Copy, Clone)]
pub enum Reflow {
No,
All,
FormatFlowed,
}
impl Default for Reflow {
fn default() -> Self {
Reflow::No
}
}
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