rust_assembler/str/
replace_str.rs

1
2/// Replaces multiple `str` at once, avoiding intermediate allocations. It returns a new `String` containing the result. Values passed by value keep ownership.
3/// 
4/// # Examples
5/// 
6/// ```
7/// 
8/// let s = "Ciao bello";
9/// 
10/// let s_replaced = replace_str!( s;
11///     ["ia", "u"],
12///     ["ll", ""]
13/// );
14/// 
15/// assert_eq!(s_replaced, "Cuo beo");
16#[macro_export]
17macro_rules! replace_str {
18    ( $string:expr; $( $pair:expr ),* ) => ({
19        let mut new_string: String = String::new();
20
21        let mut to_skip = 0;
22        let mut next_start = 0;
23        
24        'outer: for i in 0..$string.len() {
25            if to_skip > 0 {
26                to_skip -= 1;
27                continue 'outer
28            }
29
30            $(
31                unsafe {
32                    // It's the element that must be replaced.
33                    let elm_0 = *$pair.get_unchecked(0);
34                    
35                    let elm_0_len = elm_0.len();
36                    // Avoids out of bounds bugs.
37                    if i + elm_0_len > $string.len() { break 'outer }
38
39                    // First compares the first character..
40                    if *elm_0.as_bytes().get_unchecked(0) == *$string.as_bytes().get_unchecked(i) {
41                        // .. then the whole string.
42                        if *elm_0 == *$string.get_unchecked(i..i + elm_0_len) {
43                            extend_string!( new_string;
44                                $string.get_unchecked(next_start..i),
45                                $pair.get_unchecked(1)
46                            );
47                            next_start = i + elm_0_len;
48                            to_skip += elm_0_len - 1;
49                        }
50                    }
51                }
52            )*
53            
54        }
55        
56        unsafe {
57            new_string.push_str($string.get_unchecked(next_start..));
58        }
59
60        new_string
61    });
62}
rust_assembler/str/replace_str.rs

rust_assembler/str/
replace_str.rs
