Add std::str::contains

src/lib/str.rs

@@ -4,7 +4,8 @@
        unshift_char, shift_char, pop_char, push_char, is_utf8, from_chars,
        to_chars, char_len, char_at, bytes, is_ascii, shift_byte, pop_byte,
        unsafe_from_byte, unsafe_from_bytes, from_char, char_range_at,
-       str_from_cstr, sbuf, as_buf, push_byte, utf8_char_width, safe_slice;
+       str_from_cstr, sbuf, as_buf, push_byte, utf8_char_width, safe_slice,
+       contains;
 
 native "rust" mod rustrt {
     fn rust_str_push(&s: str, ch: u8);
@@ -254,6 +255,10 @@ fn match_at(haystack: str, needle: str, i: int) -> bool {
     ret -1;
 }
 
+fn contains(haystack: str, needle: str) -> bool {
+    0 <= find(haystack, needle)
+}
+
 fn starts_with(haystack: str, needle: str) -> bool {
     let haystack_len: uint = byte_len(haystack);
     let needle_len: uint = byte_len(needle);

src/test/stdtest/str.rs

@@ -304,3 +304,14 @@ fn vec_str_conversions() {
         i += 1u;
     }
 }
+
+#[test]
+fn contains() {
+    assert str::contains("abcde", "bcd");
+    assert str::contains("abcde", "abcd");
+    assert str::contains("abcde", "bcde");
+    assert str::contains("abcde", "");
+    assert str::contains("", "");
+    assert !str::contains("abcde", "def");
+    assert !str::contains("", "a");
+}