Fixed termscp panics when displaying long non-ascii filenames

src/utils/string.rs

@@ -0,0 +1,45 @@
+//! # String
+//!
+//! String related utilities
+
+/**
+ * MIT License
+ *
+ * termscp - Copyright (c) 2022 Christian Visintin
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+/// Get a substring considering utf8 characters
+pub fn secure_substring(string: &str, start: usize, end: usize) -> String {
+    assert!(end >= start);
+    string.chars().take(end).skip(start).collect()
+}
+
+#[cfg(test)]
+mod test {
+
+    use super::*;
+
+    #[test]
+    fn should_get_secure_substring() {
+        assert_eq!(secure_substring("christian", 2, 5).as_str(), "ris");
+        assert_eq!(secure_substring("россия", 3, 5).as_str(), "си");
+    }
+}