From 3ac0078e2ac28cc88da31df41b501fdbd1c0f111 Mon Sep 17 00:00:00 2001
From: Ivan Hetman <Ihromant@users.noreply.github.com>
Date: Thu, 26 Oct 2023 09:09:08 +0300
Subject: [PATCH] classlib: add cache to Byte and Short valueOf; fix
 Byte.parseByte (#832)

---
 .../org/teavm/classlib/java/lang/TByte.java    | 16 ++++++++++++----
 .../org/teavm/classlib/java/lang/TShort.java   | 18 ++++++++++++++++--
 .../org/teavm/classlib/java/lang/ByteTest.java |  8 ++++++++
 3 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TByte.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TByte.java
index ab936b522..1c0bf1fde 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TByte.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TByte.java
@@ -21,6 +21,7 @@ public class TByte extends TNumber implements TComparable<TByte> {
     public static final Class<Byte> TYPE = byte.class;
     public static final int SIZE = 8;
     public static final int BYTES = 1;
+    private static TByte[] byteCache = ensureByteCache();
     private final byte value;
 
     public TByte(byte value) {
@@ -56,9 +57,16 @@ public class TByte extends TNumber implements TComparable<TByte> {
         return value;
     }
 
-    public static TByte valueOf(byte value) {
-        // TODO: add caching
-        return new TByte(value);
+    public static TByte valueOf(byte i) {
+        return byteCache[i + 128];
+    }
+
+    private static TByte[] ensureByteCache() {
+        TByte[] byteCache = new TByte[256];
+        for (int j = 0; j < byteCache.length; ++j) {
+            byteCache[j] = new TByte((byte) (j - 128));
+        }
+        return byteCache;
     }
 
     public static String toString(byte value) {
@@ -111,7 +119,7 @@ public class TByte extends TNumber implements TComparable<TByte> {
 
     public static byte parseByte(String s, int radix) throws TNumberFormatException {
         int value = TInteger.parseInt(s, radix);
-        if (value < MIN_VALUE || value >= MAX_VALUE) {
+        if (value < MIN_VALUE || value > MAX_VALUE) {
             throw new TNumberFormatException();
         }
         return (byte) value;
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TShort.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TShort.java
index ce43efed7..67738640d 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TShort.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TShort.java
@@ -21,6 +21,7 @@ public class TShort extends TNumber implements TComparable<TShort> {
     public static final Class<Short> TYPE = short.class;
     public static final int SIZE = 16;
     public static final int BYTES = SIZE / Byte.SIZE;
+    private static TShort[] shortCache;
     private final short value;
 
     public TShort(short value) {
@@ -56,8 +57,21 @@ public class TShort extends TNumber implements TComparable<TShort> {
         return value;
     }
 
-    public static TShort valueOf(short value) {
-        return new TShort(value);
+    public static TShort valueOf(short i) {
+        if (i >= -128 && i <= 127) {
+            ensureShortCache();
+            return shortCache[i + 128];
+        }
+        return new TShort(i);
+    }
+
+    private static void ensureShortCache() {
+        if (shortCache == null) {
+            shortCache = new TShort[256];
+            for (int j = 0; j < shortCache.length; ++j) {
+                shortCache[j] = new TShort((short) (j - 128));
+            }
+        }
     }
 
     public static String toString(short value) {
diff --git a/tests/src/test/java/org/teavm/classlib/java/lang/ByteTest.java b/tests/src/test/java/org/teavm/classlib/java/lang/ByteTest.java
index 9eafcdf23..48c029cce 100644
--- a/tests/src/test/java/org/teavm/classlib/java/lang/ByteTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/lang/ByteTest.java
@@ -16,6 +16,7 @@
 package org.teavm.classlib.java.lang;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -48,4 +49,11 @@ public class ByteTest {
     public void bytes() {
         assertEquals(1, Byte.BYTES);
     }
+
+    @Test
+    public void cache() {
+        for (int b = Byte.MIN_VALUE; b <= Byte.MAX_VALUE; b++) {
+            assertSame(Byte.valueOf((byte) b), (byte) b);
+        }
+    }
 }