From 7104edb59288ba24195458d9b258adb56f260549 Mon Sep 17 00:00:00 2001
From: Jasper Siepkes <jasper@siepkes.nl>
Date: Tue, 6 Jun 2023 10:09:25 +0200
Subject: [PATCH] classlib: add stripLeading and stripTrailing methods to
 String class (#707)

The stripLeading and stripTrailing methods were added in Java 11 to the String class.

Based on the implementation of the existing strip method in TeaVM this commit adds the stripLeading() and stripTrailing() methods (and tests) to the String class in the class library.
---
 .../org/teavm/classlib/java/lang/TString.java | 16 +++++++++++++++
 .../teavm/classlib/java/lang/StringTest.java  | 20 +++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TString.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TString.java
index de4cc9d69..be541ea68 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TString.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TString.java
@@ -487,6 +487,22 @@ public class TString extends TObject implements TSerializable, TComparable<TStri
         return substring(lower, upper + 1);
     }
 
+    public TString stripLeading() {
+        var lower = 0;
+        while (lower < length() && Character.isWhitespace(charAt(lower))) {
+            ++lower;
+        }
+        return substring(lower, length());
+    }
+
+    public TString stripTrailing() {
+        var upper = length() - 1;
+        while (0 <= upper && Character.isWhitespace(charAt(upper))) {
+            --upper;
+        }
+        return substring(0, upper + 1);
+    }
+
     @Override
     public String toString() {
         return (String) (Object) this;
diff --git a/tests/src/test/java/org/teavm/classlib/java/lang/StringTest.java b/tests/src/test/java/org/teavm/classlib/java/lang/StringTest.java
index 88891a42e..9259028f1 100644
--- a/tests/src/test/java/org/teavm/classlib/java/lang/StringTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/lang/StringTest.java
@@ -209,6 +209,26 @@ public class StringTest {
         assertEquals("ab", "\t\n \u2008ab\r\f".strip());
     }
 
+    @Test
+    public void stripLeadingWorks() {
+        assertEquals("ab   ", "  ab   ".stripLeading());
+        assertEquals("ab   ", "ab   ".stripLeading());
+        assertEquals("ab", "ab".stripLeading());
+        assertEquals("a b", "a b".stripLeading());
+        assertEquals("", "  \t".stripLeading());
+        assertEquals("ab", "\t\n \u2008\r\fab".stripLeading());
+    }
+
+    @Test
+    public void stripTrailingWorks() {
+        assertEquals("  ab", "  ab   ".stripTrailing());
+        assertEquals("  ab", "  ab".stripTrailing());
+        assertEquals("ab", "ab".stripTrailing());
+        assertEquals("a b", "a b".stripTrailing());
+        assertEquals("", "  \t".stripTrailing());
+        assertEquals("ab", "ab\t\n \u2008\r\f".stripTrailing());
+    }
+
     @Test
     public void convertedToCharArray() {
         char[] array = "123".toCharArray();