From a86f000f88b7d02dc058aa477e62f6aec4c83190 Mon Sep 17 00:00:00 2001
From: Graham <gpe@openrs2.org>
Date: Tue, 10 Nov 2020 20:45:41 +0000
Subject: [PATCH] Add StreamCipher interface and a NopStreamCipher
 implementation

This will allow us to replace IsaacRandom in the future Netty
encoders/decoders with an implementation suitable for use in a unit
test.

Signed-off-by: Graham <gpe@openrs2.org>
---
 crypto/src/main/kotlin/org/openrs2/crypto/IsaacRandom.kt   | 4 ++--
 .../src/main/kotlin/org/openrs2/crypto/NopStreamCipher.kt  | 7 +++++++
 crypto/src/main/kotlin/org/openrs2/crypto/StreamCipher.kt  | 5 +++++
 3 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 crypto/src/main/kotlin/org/openrs2/crypto/NopStreamCipher.kt
 create mode 100644 crypto/src/main/kotlin/org/openrs2/crypto/StreamCipher.kt

diff --git a/crypto/src/main/kotlin/org/openrs2/crypto/IsaacRandom.kt b/crypto/src/main/kotlin/org/openrs2/crypto/IsaacRandom.kt
index df561ab3..75f3e3cd 100644
--- a/crypto/src/main/kotlin/org/openrs2/crypto/IsaacRandom.kt
+++ b/crypto/src/main/kotlin/org/openrs2/crypto/IsaacRandom.kt
@@ -1,6 +1,6 @@
 package org.openrs2.crypto
 
-public class IsaacRandom {
+public class IsaacRandom : StreamCipher {
     private var count = 0
     private val rsl: IntArray
     private val mem = IntArray(SIZE)
@@ -257,7 +257,7 @@ public class IsaacRandom {
         this.a = a
     }
 
-    public fun nextInt(): Int {
+    public override fun nextInt(): Int {
         if (count-- == 0) {
             isaac()
             count = SIZE - 1
diff --git a/crypto/src/main/kotlin/org/openrs2/crypto/NopStreamCipher.kt b/crypto/src/main/kotlin/org/openrs2/crypto/NopStreamCipher.kt
new file mode 100644
index 00000000..8b79013d
--- /dev/null
+++ b/crypto/src/main/kotlin/org/openrs2/crypto/NopStreamCipher.kt
@@ -0,0 +1,7 @@
+package org.openrs2.crypto
+
+public object NopStreamCipher : StreamCipher {
+    override fun nextInt(): Int {
+        return 0
+    }
+}
diff --git a/crypto/src/main/kotlin/org/openrs2/crypto/StreamCipher.kt b/crypto/src/main/kotlin/org/openrs2/crypto/StreamCipher.kt
new file mode 100644
index 00000000..61ff1abb
--- /dev/null
+++ b/crypto/src/main/kotlin/org/openrs2/crypto/StreamCipher.kt
@@ -0,0 +1,5 @@
+package org.openrs2.crypto
+
+public interface StreamCipher {
+    public fun nextInt(): Int
+}