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8315789: Minor HexFormat performance improvements

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Reviewed-by: rriggs
This commit is contained in:
Claes Redestad 2023-09-13 20:58:23 +00:00
parent ce93d27fe5
commit 92ad4a2399
2 changed files with 201 additions and 28 deletions
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73
src/java.base/share/classes/java/util/HexFormat.java
View File

@ -140,14 +140,6 @@ public final class HexFormat {
// Access to create strings from a byte array.
private static final JavaLangAccess jla = SharedSecrets.getJavaLangAccess();
private static final byte[] UPPERCASE_DIGITS = {
'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'A', 'B', 'C', 'D', 'E', 'F',
};
private static final byte[] LOWERCASE_DIGITS = {
'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f',
};
// Analysis has shown that generating the whole array allows the JIT to generate
// better code compared to a slimmed down array, such as one cutting off after 'f'
private static final byte[] DIGITS = {
@ -173,14 +165,22 @@ public final class HexFormat {
* The hexadecimal characters are from lowercase alpha digits.
*/
private static final HexFormat HEX_FORMAT =
new HexFormat("", "", "", LOWERCASE_DIGITS);
new HexFormat("", "", "", Case.LOWERCASE);
private static final HexFormat HEX_UPPER_FORMAT =
new HexFormat("", "", "", Case.UPPERCASE);
private static final byte[] EMPTY_BYTES = {};
private final String delimiter;
private final String prefix;
private final String suffix;
private final byte[] digits;
private final Case digitCase;
private enum Case {
LOWERCASE,
UPPERCASE
}
/**
* Returns a HexFormat with a delimiter, prefix, suffix, and array of digits.
@ -188,14 +188,14 @@ public final class HexFormat {
* @param delimiter a delimiter, non-null
* @param prefix a prefix, non-null
* @param suffix a suffix, non-null
* @param digits byte array of digits indexed by low nibble, non-null
* @param digitCase enum indicating how to case digits
* @throws NullPointerException if any argument is null
*/
private HexFormat(String delimiter, String prefix, String suffix, byte[] digits) {
private HexFormat(String delimiter, String prefix, String suffix, Case digitCase) {
this.delimiter = Objects.requireNonNull(delimiter, "delimiter");
this.prefix = Objects.requireNonNull(prefix, "prefix");
this.suffix = Objects.requireNonNull(suffix, "suffix");
this.digits = digits;
this.digitCase = digitCase;
}
/**
@ -224,7 +224,7 @@ public final class HexFormat {
* @return a {@link HexFormat} with the delimiter and lowercase characters
*/
public static HexFormat ofDelimiter(String delimiter) {
return new HexFormat(delimiter, "", "", LOWERCASE_DIGITS);
return new HexFormat(delimiter, "", "", Case.LOWERCASE);
}
/**
@ -233,7 +233,7 @@ public final class HexFormat {
* @return a copy of this {@code HexFormat} with the delimiter
*/
public HexFormat withDelimiter(String delimiter) {
return new HexFormat(delimiter, this.prefix, this.suffix, this.digits);
return new HexFormat(delimiter, this.prefix, this.suffix, this.digitCase);
}
/**
@ -243,7 +243,7 @@ public final class HexFormat {
* @return a copy of this {@code HexFormat} with the prefix
*/
public HexFormat withPrefix(String prefix) {
return new HexFormat(this.delimiter, prefix, this.suffix, this.digits);
return new HexFormat(this.delimiter, prefix, this.suffix, this.digitCase);
}
/**
@ -253,7 +253,7 @@ public final class HexFormat {
* @return a copy of this {@code HexFormat} with the suffix
*/
public HexFormat withSuffix(String suffix) {
return new HexFormat(this.delimiter, this.prefix, suffix, this.digits);
return new HexFormat(this.delimiter, this.prefix, suffix, this.digitCase);
}
/**
@ -263,7 +263,9 @@ public final class HexFormat {
* @return a copy of this {@code HexFormat} with uppercase hexadecimal characters
*/
public HexFormat withUpperCase() {
return new HexFormat(this.delimiter, this.prefix, this.suffix, UPPERCASE_DIGITS);
if (this == HEX_FORMAT)
return HEX_UPPER_FORMAT;
return new HexFormat(this.delimiter, this.prefix, this.suffix, Case.UPPERCASE);
}
/**
@ -273,7 +275,7 @@ public final class HexFormat {
* @return a copy of this {@code HexFormat} with lowercase hexadecimal characters
*/
public HexFormat withLowerCase() {
return new HexFormat(this.delimiter, this.prefix, this.suffix, LOWERCASE_DIGITS);
return new HexFormat(this.delimiter, this.prefix, this.suffix, Case.LOWERCASE);
}
/**
@ -311,7 +313,7 @@ public final class HexFormat {
* otherwise {@code false}
*/
public boolean isUpperCase() {
return Arrays.equals(digits, UPPERCASE_DIGITS);
return digitCase == Case.UPPERCASE;
}
/**
@ -401,16 +403,17 @@ public final class HexFormat {
int length = toIndex - fromIndex;
if (length > 0) {
try {
String between = suffix + delimiter + prefix;
out.append(prefix);
toHexDigits(out, bytes[fromIndex]);
if (between.isEmpty()) {
if (suffix.isEmpty() && delimiter.isEmpty() && prefix.isEmpty()) {
for (int i = 1; i < length; i++) {
toHexDigits(out, bytes[fromIndex + i]);
}
} else {
for (int i = 1; i < length; i++) {
out.append(between);
out.append(suffix);
out.append(delimiter);
out.append(prefix);
toHexDigits(out, bytes[fromIndex + i]);
}
}
@ -631,7 +634,14 @@ public final class HexFormat {
* @return the hexadecimal character for the low 4 bits {@code 0-3} of the value
*/
public char toLowHexDigit(int value) {
return (char)digits[value & 0xf];
value = value & 0xf;
if (value < 10) {
return (char)('0' + value);
}
if (digitCase == Case.LOWERCASE) {
return (char)('a' - 10 + value);
}
return (char)('A' - 10 + value);
}
/**
@ -645,7 +655,14 @@ public final class HexFormat {
* @return the hexadecimal character for the bits {@code 4-7} of the value
*/
public char toHighHexDigit(int value) {
return (char)digits[(value >> 4) & 0xf];
value = (value >> 4) & 0xf;
if (value < 10) {
return (char)('0' + value);
}
if (digitCase == Case.LOWERCASE) {
return (char)('a' - 10 + value);
}
return (char)('A' - 10 + value);
}
/**
@ -1052,7 +1069,7 @@ public final class HexFormat {
if (o == null || getClass() != o.getClass())
return false;
HexFormat otherHex = (HexFormat) o;
return Arrays.equals(digits, otherHex.digits) &&
return digitCase == otherHex.digitCase &&
delimiter.equals(otherHex.delimiter) &&
prefix.equals(otherHex.prefix) &&
suffix.equals(otherHex.suffix);
@ -1066,7 +1083,7 @@ public final class HexFormat {
@Override
public int hashCode() {
int result = Objects.hash(delimiter, prefix, suffix);
result = 31 * result + Boolean.hashCode(Arrays.equals(digits, UPPERCASE_DIGITS));
result = 31 * result + Boolean.hashCode(digitCase == Case.UPPERCASE);
return result;
}
@ -1078,7 +1095,7 @@ public final class HexFormat {
*/
@Override
public String toString() {
return escapeNL("uppercase: " + Arrays.equals(digits, UPPERCASE_DIGITS) +
return escapeNL("uppercase: " + (digitCase == Case.UPPERCASE) +
", delimiter: \"" + delimiter +
"\", prefix: \"" + prefix +
"\", suffix: \"" + suffix + "\"");

156
test/micro/org/openjdk/bench/java/util/HexFormatBench.java Normal file
View File

@ -0,0 +1,156 @@
/*
* Copyright (c) 2014, Oracle and/or its affiliates. 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.
*
* 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 org.openjdk.bench.java.util;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.infra.Blackhole;
import java.util.HexFormat;
import java.util.Random;
import java.util.concurrent.TimeUnit;
/**
* Tests java.net.URLEncoder.encode and Decoder.decode.
*/
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@State(Scope.Thread)
@Warmup(iterations = 5, time = 1)
@Measurement(iterations = 5, time = 1)
@Fork(value = 3)
public class HexFormatBench {
@Param({"512"})
public int size;
public byte[] bytes;
public StringBuilder builder = new StringBuilder(size * 2);
HexFormat LOWER_FORMATTER = HexFormat.of();
HexFormat UPPER_FORMATTER = HexFormat.of().withUpperCase();
@Setup
public void setupStrings() {
Random random = new Random(3);
bytes = new byte[size];
for (int i = 0; i < size; i++) {
bytes[i] = (byte)random.nextInt(16);
}
}
@Benchmark
public StringBuilder appenderLower() {
builder.setLength(0);
return HexFormat.of().formatHex(builder, bytes);
}
@Benchmark
public StringBuilder appenderUpper() {
builder.setLength(0);
return HexFormat.of().withUpperCase().formatHex(builder, bytes);
}
@Benchmark
public StringBuilder appenderLowerCached() {
builder.setLength(0);
return LOWER_FORMATTER.formatHex(builder, bytes);
}
@Benchmark
public StringBuilder appenderUpperCached() {
builder.setLength(0);
return UPPER_FORMATTER.formatHex(builder, bytes);
}
@Benchmark
public void toHexLower(Blackhole bh) {
for (byte b : bytes) {
bh.consume(HexFormat.of().toHighHexDigit(b));
bh.consume(HexFormat.of().toLowHexDigit(b));
}
}
@Benchmark
public void toHexUpper(Blackhole bh) {
for (byte b : bytes) {
bh.consume(HexFormat.of().withUpperCase().toHighHexDigit(b));
bh.consume(HexFormat.of().withUpperCase().toLowHexDigit(b));
}
}
@Benchmark
public void toHexLowerCached(Blackhole bh) {
for (byte b : bytes) {
bh.consume(LOWER_FORMATTER.toHighHexDigit(b));
bh.consume(LOWER_FORMATTER.toLowHexDigit(b));
}
}
@Benchmark
public void toHexUpperCached(Blackhole bh) {
for (byte b : bytes) {
bh.consume(UPPER_FORMATTER.toHighHexDigit(b));
bh.consume(UPPER_FORMATTER.toLowHexDigit(b));
}
}
@Benchmark
public void toHexDigitsByte(Blackhole bh) {
for (byte b : bytes) {
bh.consume(LOWER_FORMATTER.toHexDigits(b));
}
}
@Benchmark
public void toHexDigitsShort(Blackhole bh) {
for (short b : bytes) {
bh.consume(LOWER_FORMATTER.toHexDigits(b));
}
}
@Benchmark
public void toHexDigitsInt(Blackhole bh) {
for (int b : bytes) {
bh.consume(LOWER_FORMATTER.toHexDigits(b));
}
}
@Benchmark
public void toHexDigitsLong(Blackhole bh) {
for (long b : bytes) {
bh.consume(LOWER_FORMATTER.toHexDigits(b));
}
}
}