On Thu, 20 Jul 2023 13:57:04 GMT, Glavo <d...@openjdk.org> wrote:
>> Also... `Integer::toString` seems to be `@IntrinsicCandidate` ?
>
>> Also... `Integer::toString` seems to be `@IntrinsicCandidate` ?
>
> It's just a bytecode intrinsics, it is only replaced when used in a
> fluent-chain of StringBuilder/Buffer.
Also, note that ByteBuffer exposes its backing array (at least if the buffer is
not read only) via ByteBuffer::array. This does no copy. So in all the various
stream implementations, I believe we can really just use a ByteBuffer instead
of an array - and use ByteBuffer::array when we really need an array.
This makes it very easy to migrate some of the classes that use ByteArray.
Here's the patch for DataInputStream:
diff --git a/src/java.base/share/classes/java/io/DataInputStream.java
b/src/java.base/share/classes/java/io/DataInputStream.java
index 7192b30d5f2..b5b013cdd50 100644
--- a/src/java.base/share/classes/java/io/DataInputStream.java
+++ b/src/java.base/share/classes/java/io/DataInputStream.java
@@ -27,6 +27,8 @@ package java.io;
import jdk.internal.util.ByteArray;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
import java.util.Objects;
/**
@@ -59,7 +61,7 @@ public class DataInputStream extends FilterInputStream
implements DataInput {
super(in);
}
- private final byte[] readBuffer = new byte[8];
+ private final ByteBuffer readBuffer = ByteBuffer.allocate(8); // BIG_ENDIAN
/**
* working arrays initialized on demand by readUTF
@@ -316,8 +318,8 @@ public class DataInputStream extends FilterInputStream
implements DataInput {
* @see java.io.FilterInputStream#in
*/
public final short readShort() throws IOException {
- readFully(readBuffer, 0, 2);
- return ByteArray.getShort(readBuffer, 0);
+ readFully(readBuffer.array(), 0, 2);
+ return readBuffer.getShort(0);
}
/**
@@ -338,8 +340,8 @@ public class DataInputStream extends FilterInputStream
implements DataInput {
* @see java.io.FilterInputStream#in
*/
public final int readUnsignedShort() throws IOException {
- readFully(readBuffer, 0, 2);
- return ByteArray.getUnsignedShort(readBuffer, 0);
+ readFully(readBuffer.array(), 0, 2);
+ return Short.toUnsignedInt(readBuffer.getShort(0));
}
/**
@@ -360,8 +362,8 @@ public class DataInputStream extends FilterInputStream
implements DataInput {
* @see java.io.FilterInputStream#in
*/
public final char readChar() throws IOException {
- readFully(readBuffer, 0, 2);
- return ByteArray.getChar(readBuffer, 0);
+ readFully(readBuffer.array(), 0, 2);
+ return readBuffer.getChar(0);
}
/**
@@ -382,8 +384,8 @@ public class DataInputStream extends FilterInputStream
implements DataInput {
* @see java.io.FilterInputStream#in
*/
public final int readInt() throws IOException {
- readFully(readBuffer, 0, 4);
- return ByteArray.getInt(readBuffer, 0);
+ readFully(readBuffer.array(), 0, 4);
+ return readBuffer.getInt(0);
}
/**
@@ -404,8 +406,8 @@ public class DataInputStream extends FilterInputStream
implements DataInput {
* @see java.io.FilterInputStream#in
*/
public final long readLong() throws IOException {
- readFully(readBuffer, 0, 8);
- return ByteArray.getLong(readBuffer, 0);
+ readFully(readBuffer.array(), 0, 8);
+ return readBuffer.getLong(0);
}
/**
@@ -427,8 +429,8 @@ public class DataInputStream extends FilterInputStream
implements DataInput {
* @see java.lang.Float#intBitsToFloat(int)
*/
public final float readFloat() throws IOException {
- readFully(readBuffer, 0, 4);
- return ByteArray.getFloat(readBuffer, 0);
+ readFully(readBuffer.array(), 0, 4);
+ return readBuffer.getFloat(0);
}
/**
@@ -450,8 +452,8 @@ public class DataInputStream extends FilterInputStream
implements DataInput {
* @see java.lang.Double#longBitsToDouble(long)
*/
public final double readDouble() throws IOException {
- readFully(readBuffer, 0, 8);
- return ByteArray.getDouble(readBuffer, 0);
+ readFully(readBuffer.array(), 0, 8);
+ return readBuffer.getDouble(0);
}
private char[] lineBuffer;
It is very mechanical, and seems to pass all the jdk_io tests.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/14636#discussion_r1269527839
