Auto merge of #6876 - metajack:slice_chars-layout, r=pcwalton

Use local slice_chars

StrExt::slice_chars is deprecated and will be removed in Rust. This
lifts the implementation from Rust libstd and puts it in util::str.

This fixes a bunch of deprecation warnings in Servo.

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This commit is contained in:
bors-servo 2015-07-31 12:54:49 -06:00
commit a54404c921
7 changed files with 41 additions and 17 deletions

View file

@ -335,3 +335,27 @@ pub fn str_join<T: AsRef<str>>(strs: &[T], join: &str) -> String {
acc
})
}
// Lifted from Rust's StrExt implementation, which is being removed.
pub fn slice_chars(s: &str, begin: usize, end: usize) -> &str {
assert!(begin <= end);
let mut count = 0;
let mut begin_byte = None;
let mut end_byte = None;
// This could be even more efficient by not decoding,
// only finding the char boundaries
for (idx, _) in s.char_indices() {
if count == begin { begin_byte = Some(idx); }
if count == end { end_byte = Some(idx); break; }
count += 1;
}
if begin_byte.is_none() && count == begin { begin_byte = Some(s.len()) }
if end_byte.is_none() && count == end { end_byte = Some(s.len()) }
match (begin_byte, end_byte) {
(None, _) => panic!("slice_chars: `begin` is beyond end of string"),
(_, None) => panic!("slice_chars: `end` is beyond end of string"),
(Some(a), Some(b)) => unsafe { s.slice_unchecked(a, b) }
}
}