src/vendor/html5ever/src/util/str.rs

   1 // Copyright 2014-2017 The html5ever Project Developers. See the
   2 // COPYRIGHT file at the top-level directory of this distribution.
   3 //
   4 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   5 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   7 // option. This file may not be copied, modified, or distributed
   8 // except according to those terms.
   9
  10 use std::fmt;
  11
  12 pub fn to_escaped_string<T: fmt::Debug>(x: &T) -> String {
  13     use std::fmt::Write;
  14
  15     // FIXME: don't allocate twice
  16     let mut buf = String::new();
  17     let _ = buf.write_fmt(format_args!("{:?}", x));
  18     buf.shrink_to_fit();
  19     buf.chars().flat_map(|c| c.escape_default()).collect()
  20 }
  21
  22 /// If `c` is an ASCII letter, return the corresponding lowercase
  23 /// letter, otherwise None.
  24 pub fn lower_ascii_letter(c: char) -> Option<char> {
  25     match c {
  26         'a' ... 'z' => Some(c),
  27         'A' ... 'Z' => Some((c as u8 - b'A' + b'a') as char),
  28         _ => None
  29     }
  30 }
  31
  32 /// Is the character an ASCII alphanumeric character?
  33 pub fn is_ascii_alnum(c: char) -> bool {
  34     matches!(c, '0'...'9' | 'a'...'z' | 'A'...'Z')
  35 }
  36
  37 /// ASCII whitespace characters, as defined by
  38 /// tree construction modes that treat them specially.
  39 pub fn is_ascii_whitespace(c: char) -> bool {
  40     matches!(c, '\t' | '\r' | '\n' | '\x0C' | ' ')
  41 }
  42
  43 #[cfg(test)]
  44 #[allow(non_snake_case)]
  45 mod test {
  46     use super::{is_ascii_alnum, lower_ascii_letter};
  47
  48     test_eq!(lower_letter_a_is_a, lower_ascii_letter('a'), Some('a'));
  49     test_eq!(lower_letter_A_is_a, lower_ascii_letter('A'), Some('a'));
  50     test_eq!(lower_letter_symbol_is_None, lower_ascii_letter('!'), None);
  51     test_eq!(lower_letter_nonascii_is_None, lower_ascii_letter('\u{a66e}'), None);
  52
  53     test_eq!(is_alnum_a, is_ascii_alnum('a'), true);
  54     test_eq!(is_alnum_A, is_ascii_alnum('A'), true);
  55     test_eq!(is_alnum_1, is_ascii_alnum('1'), true);
  56     test_eq!(is_not_alnum_symbol, is_ascii_alnum('!'), false);
  57     test_eq!(is_not_alnum_nonascii, is_ascii_alnum('\u{a66e}'), false);
  58 }