src/vendor/pulldown-cmark-0.0.14/src/utils.rs

   1 // Copyright 2015 Google Inc. All rights reserved.
   2 //
   3 // Permission is hereby granted, free of charge, to any person obtaining a copy
   4 // of this software and associated documentation files (the "Software"), to deal
   5 // in the Software without restriction, including without limitation the rights
   6 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   7 // copies of the Software, and to permit persons to whom the Software is
   8 // furnished to do so, subject to the following conditions:
   9 //
  10 // The above copyright notice and this permission notice shall be included in
  11 // all copies or substantial portions of the Software.
  12 //
  13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  14 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  15 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  16 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  17 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  18 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  19 // THE SOFTWARE.
  20
  21 //! Utilities for manipulating strings.
  22
  23 use std::cmp;
  24 use std::borrow::Cow;
  25 use std::borrow::Cow::Owned;
  26
  27 fn ascii_tolower(c: u8) -> u8 {
  28     match c {
  29         b'A' ... b'Z' => c + b'a' - b'A',
  30         _ => c
  31     }
  32 }
  33
  34 // Compare two strings, with case folding for ASCII
  35 pub fn strcasecmp(a: &str, b: &str) -> cmp::Ordering {
  36     for i in 0..cmp::min(a.len(), b.len()) {
  37         match ascii_tolower(a.as_bytes()[i]).cmp(&ascii_tolower(b.as_bytes()[i])) {
  38             cmp::Ordering::Equal => (),
  39             ordering => return ordering
  40         }
  41     }
  42     a.len().cmp(&b.len())
  43 }
  44
  45 pub fn cow_append<'a>(a: Cow<'a, str>, b: Cow<'a, str>) -> Cow<'a, str> {
  46     if a.is_empty() {
  47         b
  48     } else if b.is_empty() {
  49         a
  50     } else {
  51         Owned(a.into_owned() + &b)
  52     }
  53 }