1 files changed, 107 insertions, 0 deletions
diff --git a/library/core/benches/str/char_count.rs b/library/core/benches/str/char_count.rs
new file mode 100644
index 000000000..25d9b2e29
--- /dev/null
+++ b/library/core/benches/str/char_count.rs
@@ -0,0 +1,107 @@
+use super::corpora::*;
+use test::{black_box, Bencher};
+
+macro_rules! define_benches {
+    ($( fn $name: ident($arg: ident: &str) $body: block )+) => {
+        define_benches!(mod en_tiny, en::TINY, $($name $arg $body)+);
+        define_benches!(mod en_small, en::SMALL, $($name $arg $body)+);
+        define_benches!(mod en_medium, en::MEDIUM, $($name $arg $body)+);
+        define_benches!(mod en_large, en::LARGE, $($name $arg $body)+);
+        define_benches!(mod en_huge, en::HUGE, $($name $arg $body)+);
+
+        define_benches!(mod zh_tiny, zh::TINY, $($name $arg $body)+);
+        define_benches!(mod zh_small, zh::SMALL, $($name $arg $body)+);
+        define_benches!(mod zh_medium, zh::MEDIUM, $($name $arg $body)+);
+        define_benches!(mod zh_large, zh::LARGE, $($name $arg $body)+);
+        define_benches!(mod zh_huge, zh::HUGE, $($name $arg $body)+);
+
+        define_benches!(mod ru_tiny, ru::TINY, $($name $arg $body)+);
+        define_benches!(mod ru_small, ru::SMALL, $($name $arg $body)+);
+        define_benches!(mod ru_medium, ru::MEDIUM, $($name $arg $body)+);
+        define_benches!(mod ru_large, ru::LARGE, $($name $arg $body)+);
+        define_benches!(mod ru_huge, ru::HUGE, $($name $arg $body)+);
+
+        define_benches!(mod emoji_tiny, emoji::TINY, $($name $arg $body)+);
+        define_benches!(mod emoji_small, emoji::SMALL, $($name $arg $body)+);
+        define_benches!(mod emoji_medium, emoji::MEDIUM, $($name $arg $body)+);
+        define_benches!(mod emoji_large, emoji::LARGE, $($name $arg $body)+);
+        define_benches!(mod emoji_huge, emoji::HUGE, $($name $arg $body)+);
+    };
+    (mod $mod_name: ident, $input: expr, $($name: ident $arg: ident $body: block)+) => {
+        mod $mod_name {
+            use super::*;
+            $(
+                #[bench]
+                fn $name(bencher: &mut Bencher) {
+                    let input = $input;
+                    bencher.bytes = input.len() as u64;
+                    let mut input_s = input.to_string();
+                    bencher.iter(|| {
+                        let $arg: &str = &black_box(&mut input_s);
+                        black_box($body)
+                    })
+                }
+            )+
+        }
+    };
+}
+
+define_benches! {
+    fn case00_libcore(s: &str) {
+        libcore(s)
+    }
+
+    fn case01_filter_count_cont_bytes(s: &str) {
+        filter_count_cont_bytes(s)
+    }
+
+    fn case02_iter_increment(s: &str) {
+        iterator_increment(s)
+    }
+
+    fn case03_manual_char_len(s: &str) {
+        manual_char_len(s)
+    }
+}
+
+fn libcore(s: &str) -> usize {
+    s.chars().count()
+}
+
+#[inline]
+fn utf8_is_cont_byte(byte: u8) -> bool {
+    (byte as i8) < -64
+}
+
+fn filter_count_cont_bytes(s: &str) -> usize {
+    s.as_bytes().iter().filter(|&&byte| !utf8_is_cont_byte(byte)).count()
+}
+
+fn iterator_increment(s: &str) -> usize {
+    let mut c = 0;
+    for _ in s.chars() {
+        c += 1;
+    }
+    c
+}
+
+fn manual_char_len(s: &str) -> usize {
+    let s = s.as_bytes();
+    let mut c = 0;
+    let mut i = 0;
+    let l = s.len();
+    while i < l {
+        let b = s[i];
+        if b < 0x80 {
+            i += 1;
+        } else if b < 0xe0 {
+            i += 2;
+        } else if b < 0xf0 {
+            i += 3;
+        } else {
+            i += 4;
+        }
+        c += 1;
+    }
+    c
+}