8300236: Use VarHandle access in Data(Input | Output)Stream classes

Reviewed-by: rriggs, alanb

Author: minborg

src/java.base/share/classes/java/io/Bits.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1994, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,6 +25,8 @@
 
 package java.io;
 
+import jdk.internal.util.ByteArray;
+
 import java.util.Objects;
 
 /**
@@ -54,6 +56,8 @@ public DataInputStream(InputStream in) {
         super(in);
     }
 
+    private final byte[] readBuffer = new byte[8];
+
     /**
      * working arrays initialized on demand by readUTF
      */
@@ -309,7 +313,8 @@ public final int readUnsignedByte() throws IOException {
      * @see        java.io.FilterInputStream#in
      */
     public final short readShort() throws IOException {
-        return (short) readUnsignedShort();
+        readFully(readBuffer, 0, 2);
+        return ByteArray.getShort(readBuffer, 0);
     }
 
     /**
@@ -330,12 +335,8 @@ public final short readShort() throws IOException {
      * @see        java.io.FilterInputStream#in
      */
     public final int readUnsignedShort() throws IOException {
-        InputStream in = this.in;
-        int ch1 = in.read();
-        int ch2 = in.read();
-        if ((ch1 | ch2) < 0)
-            throw new EOFException();
-        return (ch1 << 8) + (ch2 << 0);
+        readFully(readBuffer, 0, 2);
+        return ByteArray.getUnsignedShort(readBuffer, 0);
     }
 
     /**
@@ -356,7 +357,8 @@ public final int readUnsignedShort() throws IOException {
      * @see        java.io.FilterInputStream#in
      */
     public final char readChar() throws IOException {
-        return (char) readUnsignedShort();
+        readFully(readBuffer, 0, 2);
+        return ByteArray.getChar(readBuffer, 0);
     }
 
     /**
@@ -377,18 +379,10 @@ public final char readChar() throws IOException {
      * @see        java.io.FilterInputStream#in
      */
     public final int readInt() throws IOException {
-        InputStream in = this.in;
-        int ch1 = in.read();
-        int ch2 = in.read();
-        int ch3 = in.read();
-        int ch4 = in.read();
-        if ((ch1 | ch2 | ch3 | ch4) < 0)
-            throw new EOFException();
-        return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
+        readFully(readBuffer, 0, 4);
+        return ByteArray.getInt(readBuffer, 0);
     }
 
-    private final byte[] readBuffer = new byte[8];
-
     /**
      * See the general contract of the {@code readLong}
      * method of {@code DataInput}.
@@ -408,14 +402,7 @@ public final int readInt() throws IOException {
      */
     public final long readLong() throws IOException {
         readFully(readBuffer, 0, 8);
-        return (((long)readBuffer[0] << 56) +
-                ((long)(readBuffer[1] & 255) << 48) +
-                ((long)(readBuffer[2] & 255) << 40) +
-                ((long)(readBuffer[3] & 255) << 32) +
-                ((long)(readBuffer[4] & 255) << 24) +
-                ((readBuffer[5] & 255) << 16) +
-                ((readBuffer[6] & 255) <<  8) +
-                ((readBuffer[7] & 255) <<  0));
+        return ByteArray.getLong(readBuffer, 0);
     }
 
     /**
@@ -437,7 +424,8 @@ public final long readLong() throws IOException {
      * @see        java.lang.Float#intBitsToFloat(int)
      */
     public final float readFloat() throws IOException {
-        return Float.intBitsToFloat(readInt());
+        readFully(readBuffer, 0, 4);
+        return ByteArray.getFloat(readBuffer, 0);
     }
 
     /**
@@ -459,7 +447,8 @@ public final float readFloat() throws IOException {
      * @see        java.lang.Double#longBitsToDouble(long)
      */
     public final double readDouble() throws IOException {
-        return Double.longBitsToDouble(readLong());
+        readFully(readBuffer, 0, 8);
+        return ByteArray.getDouble(readBuffer, 0);
     }
 
     private char[] lineBuffer;

src/java.base/share/classes/java/io/DataInputStream.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1994, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,6 +25,8 @@
 
 package java.io;
 
+import jdk.internal.util.ByteArray;
+
 /**
  * A data output stream lets an application write primitive Java data
  * types to an output stream in a portable way. An application can
@@ -170,8 +172,7 @@ public final void writeByte(int v) throws IOException {
      * @see        java.io.FilterOutputStream#out
      */
     public final void writeShort(int v) throws IOException {
-        writeBuffer[0] = (byte)(v >>> 8);
-        writeBuffer[1] = (byte)(v >>> 0);
+        ByteArray.setUnsignedShort(writeBuffer, 0, v);
         out.write(writeBuffer, 0, 2);
         incCount(2);
     }
@@ -186,8 +187,7 @@ public final void writeShort(int v) throws IOException {
      * @see        java.io.FilterOutputStream#out
      */
     public final void writeChar(int v) throws IOException {
-        writeBuffer[0] = (byte)(v >>> 8);
-        writeBuffer[1] = (byte)(v >>> 0);
+        ByteArray.setUnsignedShort(writeBuffer, 0, v);
         out.write(writeBuffer, 0, 2);
         incCount(2);
     }
@@ -202,10 +202,7 @@ public final void writeChar(int v) throws IOException {
      * @see        java.io.FilterOutputStream#out
      */
     public final void writeInt(int v) throws IOException {
-        writeBuffer[0] = (byte)(v >>> 24);
-        writeBuffer[1] = (byte)(v >>> 16);
-        writeBuffer[2] = (byte)(v >>>  8);
-        writeBuffer[3] = (byte)(v >>>  0);
+        ByteArray.setInt(writeBuffer, 0, v);
         out.write(writeBuffer, 0, 4);
         incCount(4);
     }
@@ -220,14 +217,7 @@ public final void writeInt(int v) throws IOException {
      * @see        java.io.FilterOutputStream#out
      */
     public final void writeLong(long v) throws IOException {
-        writeBuffer[0] = (byte)(v >>> 56);
-        writeBuffer[1] = (byte)(v >>> 48);
-        writeBuffer[2] = (byte)(v >>> 40);
-        writeBuffer[3] = (byte)(v >>> 32);
-        writeBuffer[4] = (byte)(v >>> 24);
-        writeBuffer[5] = (byte)(v >>> 16);
-        writeBuffer[6] = (byte)(v >>>  8);
-        writeBuffer[7] = (byte)(v >>>  0);
+        ByteArray.setLong(writeBuffer, 0, v);
         out.write(writeBuffer, 0, 8);
         incCount(8);
     }
@@ -246,7 +236,9 @@ public final void writeLong(long v) throws IOException {
      * @see        java.lang.Float#floatToIntBits(float)
      */
     public final void writeFloat(float v) throws IOException {
-        writeInt(Float.floatToIntBits(v));
+        ByteArray.setFloat(writeBuffer, 0, v);
+        out.write(writeBuffer, 0, 4);
+        incCount(4);
     }
 
     /**
@@ -263,7 +255,9 @@ public final void writeFloat(float v) throws IOException {
      * @see        java.lang.Double#doubleToLongBits(double)
      */
     public final void writeDouble(double v) throws IOException {
-        writeLong(Double.doubleToLongBits(v));
+        ByteArray.setDouble(writeBuffer, 0, v);
+        out.write(writeBuffer, 0, 8);
+        incCount(8);
     }
 
     /**
@@ -301,8 +295,7 @@ public final void writeChars(String s) throws IOException {
         int len = s.length();
         for (int i = 0 ; i < len ; i++) {
             int v = s.charAt(i);
-            writeBuffer[0] = (byte)(v >>> 8);
-            writeBuffer[1] = (byte)(v >>> 0);
+            ByteArray.setUnsignedShort(writeBuffer, 0, v);
             out.write(writeBuffer, 0, 2);
         }
         incCount(len * 2);
@@ -379,9 +372,8 @@ static int writeUTF(String str, DataOutput out) throws IOException {
         }
 
         int count = 0;
-        bytearr[count++] = (byte) ((utflen >>> 8) & 0xFF);
-        bytearr[count++] = (byte) ((utflen >>> 0) & 0xFF);
-
+        ByteArray.setUnsignedShort(bytearr, count, utflen);
+        count += 2;
         int i = 0;
         for (i = 0; i < strlen; i++) { // optimized for initial run of ASCII
             int c = str.charAt(i);