1 files changed, 127 insertions, 0 deletions
diff --git a/components/style/str.rs b/components/style/str.rs
new file mode 100644
index 00000000000..73518625b6e
--- /dev/null
+++ b/components/style/str.rs
@@ -0,0 +1,127 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use num_traits::ToPrimitive;
+use std::convert::AsRef;
+use std::iter::{Filter, Peekable};
+use std::str::Split;
+
+pub type StaticCharVec = &'static [char];
+pub type StaticStringVec = &'static [&'static str];
+
+/// A "space character" according to:
+///
+/// https://html.spec.whatwg.org/multipage/#space-character
+pub static HTML_SPACE_CHARACTERS: StaticCharVec = &[
+    '\u{0020}',
+    '\u{0009}',
+    '\u{000a}',
+    '\u{000c}',
+    '\u{000d}',
+];
+
+#[inline]
+pub fn char_is_whitespace(c: char) -> bool {
+    HTML_SPACE_CHARACTERS.contains(&c)
+}
+
+pub fn is_whitespace(s: &str) -> bool {
+    s.chars().all(char_is_whitespace)
+}
+
+pub fn split_html_space_chars<'a>(s: &'a str) ->
+                                  Filter<Split<'a, StaticCharVec>, fn(&&str) -> bool> {
+    fn not_empty(&split: &&str) -> bool { !split.is_empty() }
+    s.split(HTML_SPACE_CHARACTERS).filter(not_empty as fn(&&str) -> bool)
+}
+
+pub fn split_commas<'a>(s: &'a str) -> Filter<Split<'a, char>, fn(&&str) -> bool> {
+    fn not_empty(&split: &&str) -> bool { !split.is_empty() }
+    s.split(',').filter(not_empty as fn(&&str) -> bool)
+}
+
+fn is_ascii_digit(c: &char) -> bool {
+    match *c {
+        '0'...'9' => true,
+        _ => false,
+    }
+}
+
+fn is_decimal_point(c: char) -> bool {
+    c == '.'
+}
+
+fn is_exponent_char(c: char) -> bool {
+    match c {
+        'e' | 'E' => true,
+        _ => false,
+    }
+}
+
+pub fn read_numbers<I: Iterator<Item=char>>(mut iter: Peekable<I>) -> (Option<i64>, usize) {
+    match iter.peek() {
+        Some(c) if is_ascii_digit(c) => (),
+        _ => return (None, 0),
+    }
+
+    iter.take_while(is_ascii_digit).map(|d| {
+        d as i64 - '0' as i64
+    }).fold((Some(0i64), 0), |accumulator, d| {
+        let digits = accumulator.0.and_then(|accumulator| {
+            accumulator.checked_mul(10)
+        }).and_then(|accumulator| {
+            accumulator.checked_add(d)
+        });
+        (digits, accumulator.1 + 1)
+    })
+}
+
+pub fn read_fraction<I: Iterator<Item=char>>(mut iter: Peekable<I>,
+                                             mut divisor: f64,
+                                             value: f64) -> (f64, usize) {
+    match iter.peek() {
+        Some(c) if is_decimal_point(*c) => (),
+        _ => return (value, 0),
+    }
+    iter.next();
+
+    iter.take_while(is_ascii_digit).map(|d|
+        d as i64 - '0' as i64
+    ).fold((value, 1), |accumulator, d| {
+        divisor *= 10f64;
+        (accumulator.0 + d as f64 / divisor,
+            accumulator.1 + 1)
+    })
+}
+
+pub fn read_exponent<I: Iterator<Item=char>>(mut iter: Peekable<I>) -> Option<i32> {
+    match iter.peek() {
+        Some(c) if is_exponent_char(*c) => (),
+        _ => return None,
+    }
+    iter.next();
+
+    match iter.peek() {
+        None => None,
+        Some(&'-') => {
+            iter.next();
+            read_numbers(iter).0.map(|exp| -exp.to_i32().unwrap_or(0))
+        }
+        Some(&'+') => {
+            iter.next();
+            read_numbers(iter).0.map(|exp| exp.to_i32().unwrap_or(0))
+        }
+        Some(_) => read_numbers(iter).0.map(|exp| exp.to_i32().unwrap_or(0))
+    }
+}
+
+pub fn str_join<I, T>(strs: I, join: &str) -> String
+    where I: IntoIterator<Item=T>, T: AsRef<str>,
+{
+    strs.into_iter().enumerate().fold(String::new(), |mut acc, (i, s)| {
+        if i > 0 { acc.push_str(join); }
+        acc.push_str(s.as_ref());
+        acc
+    })
+}