Function str_indexof 

pub fn str_indexof(s1: &SmtString, s2: &SmtString, i: i32) -> i32

Index of the first occurrence of s2 in s1, starting from index i

• If 0 <= i < s1.len and s2 occurs in s1[i ..] then return the index j >= i of the first occurrence of s2 in s1[i ..].
• Return -1 if i < 0 or i >= s1.len or s2 does not occur in s1[i ..]

Examples

use aws_smt_strings::smt_strings::*;

let s1 = SmtString::from("abcdef");
let s2 = SmtString::from("cde");
let s3 = SmtString::from("cdd");

assert_eq!(str_indexof(&s1, &s2, 0), 2);
assert_eq!(str_indexof(&s1, &s2, 2), 2);
assert_eq!(str_indexof(&s1, &s2, 3), -1);
assert_eq!(str_indexof(&s1, &s3, 0), -1);