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8339699: Optimize DataOutputStream writeUTF

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Reviewed-by: liach, bpb
This commit is contained in:
Shaojin Wen 2024-10-04 22:35:03 +00:00
parent 559289487d
commit b42fbf43df
5 changed files with 252 additions and 182 deletions
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42
src/java.base/share/classes/java/io/DataOutputStream.java
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@ -1,5 +1,6 @@
/*
* Copyright (c) 1994, 2023, 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.
*
* This code is free software; you can redistribute it and/or modify it
@ -25,8 +26,13 @@
package java.io;
import jdk.internal.access.JavaLangAccess;
import jdk.internal.access.SharedSecrets;
import jdk.internal.util.ByteArray;
import static jdk.internal.util.ModifiedUtf.putChar;
import static jdk.internal.util.ModifiedUtf.utfLen;
/**
* A data output stream lets an application write primitive Java data
* types to an output stream in a portable way. An application can
@ -44,6 +50,8 @@ import jdk.internal.util.ByteArray;
* @since 1.0
*/
public class DataOutputStream extends FilterOutputStream implements DataOutput {
private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
/**
* The number of bytes written to the data output stream so far.
* If this counter overflows, it will be wrapped to Integer.MAX_VALUE.
@ -352,15 +360,11 @@ public class DataOutputStream extends FilterOutputStream implements DataOutput {
* {@code str} would exceed 65535 bytes in length
* @throws IOException if some other I/O error occurs.
*/
@SuppressWarnings("deprecation")
static int writeUTF(String str, DataOutput out) throws IOException {
final int strlen = str.length();
int utflen = strlen; // optimized for ASCII
for (int i = 0; i < strlen; i++) {
int c = str.charAt(i);
if (c >= 0x80 || c == 0)
utflen += (c >= 0x800) ? 2 : 1;
}
int countNonZeroAscii = JLA.countNonZeroAscii(str);
int utflen = utfLen(str, countNonZeroAscii);
if (utflen > 65535 || /* overflow */ utflen < strlen)
throw new UTFDataFormatException(tooLongMsg(str, utflen));
@ -377,25 +381,11 @@ public class DataOutputStream extends FilterOutputStream implements DataOutput {
int count = 0;
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);
if (c >= 0x80 || c == 0) break;
bytearr[count++] = (byte) c;
}
str.getBytes(0, countNonZeroAscii, bytearr, count);
count += countNonZeroAscii;
for (; i < strlen; i++) {
int c = str.charAt(i);
if (c < 0x80 && c != 0) {
bytearr[count++] = (byte) c;
} else if (c >= 0x800) {
bytearr[count++] = (byte) (0xE0 | ((c >> 12) & 0x0F));
bytearr[count++] = (byte) (0x80 | ((c >> 6) & 0x3F));
bytearr[count++] = (byte) (0x80 | ((c >> 0) & 0x3F));
} else {
bytearr[count++] = (byte) (0xC0 | ((c >> 6) & 0x1F));
bytearr[count++] = (byte) (0x80 | ((c >> 0) & 0x3F));
}
for (int i = countNonZeroAscii; i < strlen;) {
count = putChar(bytearr, count, str.charAt(i++));
}
out.write(bytearr, 0, utflen + 2);
return utflen + 2;