From 567571cf6cbc657e6f4713dea38bda7f34eb63ac Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 11:33:15 +0100
Subject: [PATCH] Kotlin conversion: SessionKey

---
 sop-java/src/main/java/sop/SessionKey.java | 80 ----------------------
 sop-java/src/main/kotlin/sop/SessionKey.kt | 48 +++++++++++++
 2 files changed, 48 insertions(+), 80 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/SessionKey.java
 create mode 100644 sop-java/src/main/kotlin/sop/SessionKey.kt

diff --git a/sop-java/src/main/java/sop/SessionKey.java b/sop-java/src/main/java/sop/SessionKey.java
deleted file mode 100644
index 722666d..0000000
--- a/sop-java/src/main/java/sop/SessionKey.java
+++ /dev/null
@@ -1,80 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import java.util.Arrays;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
-import sop.util.HexUtil;
-
-public class SessionKey {
-
-    private static final Pattern PATTERN = Pattern.compile("^(\\d):([0-9A-F]+)$");
-
-    private final byte algorithm;
-    private final byte[] sessionKey;
-
-    public SessionKey(byte algorithm, byte[] sessionKey) {
-        this.algorithm = algorithm;
-        this.sessionKey = sessionKey;
-    }
-
-    /**
-     * Return the symmetric algorithm octet.
-     *
-     * @return algorithm id
-     */
-    public byte getAlgorithm() {
-        return algorithm;
-    }
-
-    /**
-     * Return the session key.
-     *
-     * @return session key
-     */
-    public byte[] getKey() {
-        return sessionKey;
-    }
-
-    @Override
-    public int hashCode() {
-        return getAlgorithm() * 17 + Arrays.hashCode(getKey());
-    }
-
-    @Override
-    public boolean equals(Object other) {
-        if (other == null) {
-            return false;
-        }
-        if (this == other) {
-            return true;
-        }
-        if (!(other instanceof SessionKey)) {
-            return false;
-        }
-
-        SessionKey otherKey = (SessionKey) other;
-        return getAlgorithm() == otherKey.getAlgorithm() && Arrays.equals(getKey(), otherKey.getKey());
-    }
-
-    public static SessionKey fromString(String string) {
-        string = string.trim().toUpperCase().replace("\n", "");
-        Matcher matcher = PATTERN.matcher(string);
-        if (!matcher.matches()) {
-            throw new IllegalArgumentException("Provided session key does not match expected format.");
-        }
-        byte algorithm = Byte.parseByte(matcher.group(1));
-        String key = matcher.group(2);
-
-        return new SessionKey(algorithm, HexUtil.hexToBytes(key));
-    }
-
-    @Override
-    public String toString() {
-        return Integer.toString(getAlgorithm()) + ':' + HexUtil.bytesToHex(sessionKey);
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/SessionKey.kt b/sop-java/src/main/kotlin/sop/SessionKey.kt
new file mode 100644
index 0000000..af230f3
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/SessionKey.kt
@@ -0,0 +1,48 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import sop.util.HexUtil
+
+/**
+ * Class representing a symmetric session key.
+ *
+ * @param algorithm symmetric key algorithm ID
+ * @param key [ByteArray] containing the session key
+ */
+data class SessionKey(val algorithm: Byte, val key: ByteArray) {
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as SessionKey
+
+        if (algorithm != other.algorithm) return false
+        if (!key.contentEquals(other.key)) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var hashCode = algorithm.toInt()
+        hashCode = 31 * hashCode + key.contentHashCode()
+        return hashCode
+    }
+
+    override fun toString(): String = "$algorithm:${HexUtil.bytesToHex(key)}"
+
+    companion object {
+
+        @JvmStatic private val PATTERN = "^(\\d):([0-9A-F]+)$".toPattern()
+
+        @JvmStatic
+        fun fromString(string: String): SessionKey {
+            val matcher = PATTERN.matcher(string.trim().uppercase().replace("\n", ""))
+            require(matcher.matches()) { "Provided session key does not match expected format." }
+            return SessionKey(matcher.group(1).toByte(), HexUtil.hexToBytes(matcher.group(2)))
+        }
+    }
+}