jdk/src/java.base/share/classes/java/lang/StringCoding.java
Shaojin Wen cb9f5c5791 8339290: Optimize ClassFile Utf8EntryImpl#writeTo
Reviewed-by: redestad, liach
2024-09-05 11:45:49 +00:00

127 lines
4 KiB
Java

/*
* Copyright (c) 2000, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.lang;
import jdk.internal.vm.annotation.IntrinsicCandidate;
/**
* Utility class for string encoding and decoding.
*/
class StringCoding {
private StringCoding() { }
/**
* Count the number of leading non-zero ascii chars in the range.
*/
public static int countNonZeroAscii(String s) {
byte[] value = s.value();
if (s.isLatin1()) {
return countNonZeroAsciiLatin1(value, 0, value.length);
} else {
return countNonZeroAsciiUTF16(value, 0, s.length());
}
}
/**
* Count the number of non-zero ascii chars in the range.
*/
public static int countNonZeroAsciiLatin1(byte[] ba, int off, int len) {
int limit = off + len;
for (int i = off; i < limit; i++) {
if (ba[i] <= 0) {
return i - off;
}
}
return len;
}
/**
* Count the number of leading non-zero ascii chars in the range.
*/
public static int countNonZeroAsciiUTF16(byte[] ba, int off, int strlen) {
int limit = off + strlen;
for (int i = off; i < limit; i++) {
char c = StringUTF16.charAt(ba, i);
if (c == 0 || c > 0x7F) {
return i - off;
}
}
return strlen;
}
public static boolean hasNegatives(byte[] ba, int off, int len) {
return countPositives(ba, off, len) != len;
}
/**
* Count the number of leading positive bytes in the range.
*
* @implSpec the implementation must return len if there are no negative
* bytes in the range. If there are negative bytes, the implementation must return
* a value that is less than or equal to the index of the first negative byte
* in the range.
*/
@IntrinsicCandidate
public static int countPositives(byte[] ba, int off, int len) {
int limit = off + len;
for (int i = off; i < limit; i++) {
if (ba[i] < 0) {
return i - off;
}
}
return len;
}
@IntrinsicCandidate
public static int implEncodeISOArray(byte[] sa, int sp,
byte[] da, int dp, int len) {
int i = 0;
for (; i < len; i++) {
char c = StringUTF16.getChar(sa, sp++);
if (c > '\u00FF')
break;
da[dp++] = (byte)c;
}
return i;
}
@IntrinsicCandidate
public static int implEncodeAsciiArray(char[] sa, int sp,
byte[] da, int dp, int len)
{
int i = 0;
for (; i < len; i++) {
char c = sa[sp++];
if (c >= '\u0080')
break;
da[dp++] = (byte)c;
}
return i;
}
}