Add benchmarks for char iterators

Author: Kmeakin

library/coretests/benches/str/iter.rs

@@ -16,3 +16,59 @@ fn chars_advance_by_0010(b: &mut Bencher) {
 fn chars_advance_by_0001(b: &mut Bencher) {
     b.iter(|| black_box(corpora::ru::LARGE).chars().advance_by(1));
 }
+
+mod chars_sum {
+    use super::*;
+
+    fn bench(b: &mut Bencher, corpus: &str) {
+        b.iter(|| corpus.chars().map(|c| c as u32).sum::<u32>())
+    }
+
+    #[bench]
+    fn en(b: &mut Bencher) {
+        bench(b, corpora::en::HUGE);
+    }
+
+    #[bench]
+    fn zh(b: &mut Bencher) {
+        bench(b, corpora::zh::HUGE);
+    }
+
+    #[bench]
+    fn ru(b: &mut Bencher) {
+        bench(b, corpora::zh::HUGE);
+    }
+
+    #[bench]
+    fn emoji(b: &mut Bencher) {
+        bench(b, corpora::zh::HUGE);
+    }
+}
+
+mod chars_sum_rev {
+    use super::*;
+
+    fn bench(b: &mut Bencher, corpus: &str) {
+        b.iter(|| corpus.chars().rev().map(|c| c as u32).sum::<u32>())
+    }
+
+    #[bench]
+    fn en(b: &mut Bencher) {
+        bench(b, corpora::en::HUGE);
+    }
+
+    #[bench]
+    fn zh(b: &mut Bencher) {
+        bench(b, corpora::zh::HUGE);
+    }
+
+    #[bench]
+    fn ru(b: &mut Bencher) {
+        bench(b, corpora::zh::HUGE);
+    }
+
+    #[bench]
+    fn emoji(b: &mut Bencher) {
+        bench(b, corpora::zh::HUGE);
+    }
+}