1 files changed, 61 insertions, 0 deletions
diff --git a/ui/src/main/java/com/wireguard/android/model/TunnelComparator.kt b/ui/src/main/java/com/wireguard/android/model/TunnelComparator.kt
new file mode 100644
index 00000000..e6b46a54
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/android/model/TunnelComparator.kt
@@ -0,0 +1,61 @@
+/*
+ * Copyright © 2017-2023 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.android.model
+
+object TunnelComparator : Comparator<String> {
+    private class NaturalSortString(originalString: String) {
+        class NaturalSortToken(val maybeString: String?, val maybeNumber: Int?) : Comparable<NaturalSortToken> {
+            override fun compareTo(other: NaturalSortToken): Int {
+                if (maybeString == null) {
+                    if (other.maybeString != null || maybeNumber!! < other.maybeNumber!!) {
+                        return -1
+                    } else if (maybeNumber > other.maybeNumber) {
+                        return 1
+                    }
+                } else if (other.maybeString == null || maybeString > other.maybeString) {
+                    return 1
+                } else if (maybeString < other.maybeString) {
+                    return -1
+                }
+                return 0
+            }
+        }
+
+        val tokens: MutableList<NaturalSortToken> = ArrayList()
+
+        init {
+            for (s in NATURAL_SORT_DIGIT_FINDER.findAll(originalString.split(WHITESPACE_FINDER).joinToString(" ").lowercase())) {
+                try {
+                    val n = s.value.toInt()
+                    tokens.add(NaturalSortToken(null, n))
+                } catch (_: NumberFormatException) {
+                    tokens.add(NaturalSortToken(s.value, null))
+                }
+            }
+        }
+
+        private companion object {
+            private val NATURAL_SORT_DIGIT_FINDER = Regex("""\d+|\D+""")
+            private val WHITESPACE_FINDER = Regex("""\s""")
+        }
+    }
+
+    override fun compare(a: String, b: String): Int {
+        if (a == b)
+            return 0
+        val na = NaturalSortString(a)
+        val nb = NaturalSortString(b)
+        for (i in 0 until nb.tokens.size) {
+            if (i == na.tokens.size) {
+                return -1
+            }
+            val c = na.tokens[i].compareTo(nb.tokens[i])
+            if (c != 0)
+                return c
+        }
+        return 1
+    }
+}