feat: str ext

Author: Thaumy

src/infra/mod.rs

@@ -4,5 +4,6 @@ pub mod iter;
 pub mod json;
 pub mod option;
 pub mod result;
+pub mod str;
 pub mod time;
 pub mod vec;

src/infra/str.rs

@@ -0,0 +1,93 @@
+use std::ops::ControlFlow;
+use unicode_width::UnicodeWidthChar;
+
+pub trait StrExt {
+    fn width_split_head(&self, head_width: usize) -> (&str, &str);
+    fn width_split(&self, width: usize) -> Option<Vec<&str>>;
+}
+
+impl StrExt for str {
+    fn width_split_head(&self, head_width: usize) -> (&str, &str) {
+        let mut left_take = head_width;
+        let mut take_bytes = 0;
+        self.chars().try_for_each(|c| {
+            let current_width = c.width_cjk().unwrap_or(0);
+            if left_take > 0 {
+                if left_take >= current_width {
+                    left_take -= current_width;
+                    take_bytes += c.len_utf8();
+                    ControlFlow::Continue(())
+                } else {
+                    left_take = 0;
+                    ControlFlow::Break(())
+                }
+            } else {
+                ControlFlow::Break(())
+            }
+        });
+        self.split_at(take_bytes)
+    }
+
+    fn width_split(&self, width: usize) -> Option<Vec<&str>> {
+        let mut vec = vec![];
+        let mut str = self;
+        loop {
+            let (head, tail) = str.width_split_head(width);
+            // No split strategy exist, return None
+            if head == "" {
+                return None;
+            }
+            vec.push(head);
+            if tail == "" {
+                break;
+            }
+            str = tail;
+        }
+        Some(vec)
+    }
+}
+
+#[test]
+fn test_width_split_head() {
+    let text = "测试test⭐";
+    assert_eq!(text.width_split_head(0), ("", "测试test⭐"));
+    assert_eq!(text.width_split_head(1), ("", "测试test⭐"));
+    assert_eq!(text.width_split_head(2), ("测", "试test⭐"));
+    assert_eq!(text.width_split_head(3), ("测", "试test⭐"));
+    assert_eq!(text.width_split_head(4), ("测试", "test⭐"));
+    assert_eq!(text.width_split_head(5), ("测试t", "est⭐"));
+    assert_eq!(text.width_split_head(9), ("测试test", "⭐"));
+    assert_eq!(text.width_split_head(10), ("测试test⭐", ""));
+    assert_eq!(text.width_split_head(11), ("测试test⭐", ""));
+}
+
+#[test]
+fn test_width_split() {
+    let text = "测试test⭐测试test⭐";
+    assert_eq!(text.width_split(0), None);
+    assert_eq!(text.width_split(1), None);
+    assert_eq!(
+        text.width_split(2),
+        vec!["测", "试", "te", "st", "⭐", "测", "试", "te", "st", "⭐"].into_some()
+    );
+    assert_eq!(
+        text.width_split(3),
+        vec!["测", "试t", "est", "⭐", "测", "试t", "est", "⭐"].into_some()
+    );
+    assert_eq!(
+        text.width_split(4),
+        vec!["测试", "test", "⭐测", "试te", "st⭐"].into_some()
+    );
+    assert_eq!(
+        text.width_split(19),
+        vec!["测试test⭐测试test", "⭐"].into_some()
+    );
+    assert_eq!(
+        text.width_split(20),
+        vec!["测试test⭐测试test⭐"].into_some()
+    );
+    assert_eq!(
+        text.width_split(21),
+        vec!["测试test⭐测试test⭐"].into_some()
+    );
+}