gostd_bytes

Function IndexFunc

Source 
pub fn IndexFunc(s: impl AsRef<[byte]>, f: fn(rune) -> bool) -> int
Expand description

IndexFunc interprets s as a sequence of UTF-8-encoded code points. It returns the byte index in s of the first Unicode code point satisfying f(c), or -1 if none do.

zh-cn IndexFunc将满足f（rune）的第一个Unicode代码点的索引返回到s，如果没有，则返回-1。

§Example

use gostd_bytes as bytes;

   /* fn f(c: u32) -> bool {
       let s = char::from_u32(c).unwrap();
       !s.is_ascii()
   } */
   // 用上面注释掉的函数也可以，用下面的匿名函数也可以。
   let f = |c: u32| {
       let s = char::from_u32(c).expect("u32 to char failed!");
       !s.is_ascii()
   };
   assert_eq!(7, bytes::IndexFunc("Hello, 世界", f));
   assert_eq!(-1, bytes::IndexFunc("Hello, world", f));
   assert_eq!(7, bytes::IndexFunc("Hello, 世界".as_bytes(), f));
   assert_eq!(-1, bytes::IndexFunc("Hello, world".to_string(), f));