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8340232: Optimize DataInputStream::readUTF

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Reviewed-by: liach, bpb
This commit is contained in:
Shaojin Wen 2024-09-20 17:54:06 +00:00
parent ab81197d0d
commit 40fba14812
1 changed files with 40 additions and 14 deletions
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54
src/java.base/share/classes/java/io/DataInputStream.java
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@ -1,5 +1,6 @@
/* /*
* Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2024, Alibaba Group Holding Limited. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
* *
* This code is free software; you can redistribute it and/or modify it * This code is free software; you can redistribute it and/or modify it
@ -25,8 +26,11 @@
package java.io; package java.io;
import jdk.internal.access.JavaLangAccess;
import jdk.internal.access.SharedSecrets;
import jdk.internal.util.ByteArray; import jdk.internal.util.ByteArray;
import java.nio.charset.StandardCharsets;
import java.util.Objects; import java.util.Objects;
/** /**
@ -45,6 +49,7 @@ import java.util.Objects;
* @since 1.0 * @since 1.0
*/ */
public class DataInputStream extends FilterInputStream implements DataInput { public class DataInputStream extends FilterInputStream implements DataInput {
private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
private static final byte[] EMPTY_BYTE_ARRAY = new byte[0]; private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
private static final char[] EMPTY_CHAR_ARRAY = new char[0]; private static final char[] EMPTY_CHAR_ARRAY = new char[0];
@ -573,18 +578,16 @@ loop: while (true) {
*/ */
public static final String readUTF(DataInput in) throws IOException { public static final String readUTF(DataInput in) throws IOException {
int utflen = in.readUnsignedShort(); int utflen = in.readUnsignedShort();
byte[] bytearr; byte[] bytearr = null;
char[] chararr;
if (in instanceof DataInputStream dis) { if (in instanceof DataInputStream dis) {
if (dis.bytearr.length < utflen) { if (dis.bytearr.length >= utflen) {
dis.bytearr = new byte[utflen*2]; bytearr = dis.bytearr;
dis.chararr = new char[utflen*2];
} }
chararr = dis.chararr; }
bytearr = dis.bytearr; boolean trusted = false;
} else { if (bytearr == null) {
bytearr = new byte[utflen]; bytearr = new byte[utflen];
chararr = new char[utflen]; trusted = true;
} }
int c, char2, char3; int c, char2, char3;
@ -592,12 +595,35 @@ loop: while (true) {
int chararr_count=0; int chararr_count=0;
in.readFully(bytearr, 0, utflen); in.readFully(bytearr, 0, utflen);
int ascii = JLA.countPositives(bytearr, 0, utflen);
if (ascii == utflen) {
String str;
if (trusted) {
str = JLA.newStringNoRepl(bytearr, StandardCharsets.ISO_8859_1);
} else {
str = new String(bytearr, 0, utflen, StandardCharsets.ISO_8859_1);
}
return str;
}
if (trusted && in instanceof DataInputStream dis) {
dis.bytearr = bytearr;
trusted = false;
}
while (count < utflen) { char[] chararr;
c = (int) bytearr[count] & 0xff; if (in instanceof DataInputStream dis) {
if (c > 127) break; if (dis.chararr.length < (utflen << 1)) {
count++; dis.chararr = new char[utflen << 1];
chararr[chararr_count++]=(char)c; }
chararr = dis.chararr;
} else {
chararr = new char[utflen];
}
if (ascii != 0) {
JLA.inflateBytesToChars(bytearr, 0, chararr, 0, ascii);
count += ascii;
chararr_count += ascii;
} }
while (count < utflen) { while (count < utflen) {