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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) 2024, Alibaba Group Holding Limited. 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
@ -25,8 +26,11 @@
package java.io;
import jdk.internal.access.JavaLangAccess;
import jdk.internal.access.SharedSecrets;
import jdk.internal.util.ByteArray;
import java.nio.charset.StandardCharsets;
import java.util.Objects;
/**
@ -45,6 +49,7 @@ import java.util.Objects;
* @since 1.0
*/
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 char[] EMPTY_CHAR_ARRAY = new char[0];
@ -573,18 +578,16 @@ loop: while (true) {
*/
public static final String readUTF(DataInput in) throws IOException {
int utflen = in.readUnsignedShort();
byte[] bytearr;
char[] chararr;
byte[] bytearr = null;
if (in instanceof DataInputStream dis) {
if (dis.bytearr.length < utflen) {
dis.bytearr = new byte[utflen*2];
dis.chararr = new char[utflen*2];
if (dis.bytearr.length >= utflen) {
bytearr = dis.bytearr;
}
chararr = dis.chararr;
bytearr = dis.bytearr;
} else {
}
boolean trusted = false;
if (bytearr == null) {
bytearr = new byte[utflen];
chararr = new char[utflen];
trusted = true;
}
int c, char2, char3;
@ -592,12 +595,35 @@ loop: while (true) {
int chararr_count=0;
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) {
c = (int) bytearr[count] & 0xff;
if (c > 127) break;
count++;
chararr[chararr_count++]=(char)c;
char[] chararr;
if (in instanceof DataInputStream dis) {
if (dis.chararr.length < (utflen << 1)) {
dis.chararr = new char[utflen << 1];
}
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) {