diff --git a/src/java.base/share/classes/java/lang/String.java b/src/java.base/share/classes/java/lang/String.java
index 1897a06cd60..1b5b5efb72b 100644
--- a/src/java.base/share/classes/java/lang/String.java
+++ b/src/java.base/share/classes/java/lang/String.java
@@ -51,6 +51,7 @@ import java.util.stream.IntStream;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
+import jdk.internal.util.ArraysSupport;
import jdk.internal.util.Preconditions;
import jdk.internal.vm.annotation.ForceInline;
import jdk.internal.vm.annotation.IntrinsicCandidate;
@@ -1272,8 +1273,7 @@ public final class String
}
private static void throwUnmappable(byte[] val) {
- int dp = 0;
- while (dp < val.length && val[dp] >=0) { dp++; }
+ int dp = StringCoding.countPositives(val, 0, val.length);
throwUnmappable(dp);
}
@@ -1870,23 +1870,17 @@ public final class String
if (len != sb.length()) {
return false;
}
- byte v1[] = value;
- byte v2[] = sb.getValue();
+ byte[] v1 = value;
+ byte[] v2 = sb.getValue();
byte coder = coder();
if (coder == sb.getCoder()) {
- int n = v1.length;
- for (int i = 0; i < n; i++) {
- if (v1[i] != v2[i]) {
- return false;
- }
- }
+ return v1.length <= v2.length && ArraysSupport.mismatch(v1, v2, v1.length) < 0;
} else {
if (coder != LATIN1) { // utf16 str and latin1 abs can never be "equal"
return false;
}
return StringUTF16.contentEquals(v1, v2, len);
}
- return true;
}
/**
@@ -2024,8 +2018,8 @@ public final class String
* lexicographically greater than the string argument.
*/
public int compareTo(String anotherString) {
- byte v1[] = value;
- byte v2[] = anotherString.value;
+ byte[] v1 = value;
+ byte[] v2 = anotherString.value;
byte coder = coder();
if (coder == anotherString.coder()) {
return coder == LATIN1 ? StringLatin1.compareTo(v1, v2)
@@ -2060,8 +2054,8 @@ public final class String
private static final long serialVersionUID = 8575799808933029326L;
public int compare(String s1, String s2) {
- byte v1[] = s1.value;
- byte v2[] = s2.value;
+ byte[] v1 = s1.value;
+ byte[] v2 = s2.value;
byte coder = s1.coder();
if (coder == s2.coder()) {
return coder == LATIN1 ? StringLatin1.compareToCI(v1, v2)
@@ -2136,26 +2130,23 @@ public final class String
* {@code false} otherwise.
*/
public boolean regionMatches(int toffset, String other, int ooffset, int len) {
- byte tv[] = value;
- byte ov[] = other.value;
// Note: toffset, ooffset, or len might be near -1>>>1.
if ((ooffset < 0) || (toffset < 0) ||
(toffset > (long)length() - len) ||
(ooffset > (long)other.length() - len)) {
return false;
}
+ byte[] tv = value;
+ byte[] ov = other.value;
byte coder = coder();
if (coder == other.coder()) {
- if (!isLatin1() && (len > 0)) {
- toffset = toffset << 1;
- ooffset = ooffset << 1;
- len = len << 1;
- }
- while (len-- > 0) {
- if (tv[toffset++] != ov[ooffset++]) {
- return false;
- }
+ if (coder == UTF16) {
+ toffset <<= UTF16;
+ ooffset <<= UTF16;
+ len <<= UTF16;
}
+ return ArraysSupport.mismatch(tv, toffset,
+ ov, ooffset, len) < 0;
} else {
if (coder == LATIN1) {
while (len-- > 0) {
@@ -2235,8 +2226,8 @@ public final class String
|| (ooffset > (long)other.length() - len)) {
return false;
}
- byte tv[] = value;
- byte ov[] = other.value;
+ byte[] tv = value;
+ byte[] ov = other.value;
byte coder = coder();
if (coder == other.coder()) {
return coder == LATIN1
@@ -2270,18 +2261,17 @@ public final class String
if (toffset < 0 || toffset > length() - prefix.length()) {
return false;
}
- byte ta[] = value;
- byte pa[] = prefix.value;
+ byte[] ta = value;
+ byte[] pa = prefix.value;
int po = 0;
int pc = pa.length;
byte coder = coder();
if (coder == prefix.coder()) {
- int to = (coder == LATIN1) ? toffset : toffset << 1;
- while (po < pc) {
- if (ta[to++] != pa[po++]) {
- return false;
- }
+ if (coder == UTF16) {
+ toffset <<= UTF16;
}
+ return ArraysSupport.mismatch(ta, toffset,
+ pa, 0, pc) < 0;
} else {
if (coder == LATIN1) { // && pcoder == UTF16
return false;
diff --git a/src/java.base/share/classes/java/lang/StringLatin1.java b/src/java.base/share/classes/java/lang/StringLatin1.java
index 526d752f058..7749597a24a 100644
--- a/src/java.base/share/classes/java/lang/StringLatin1.java
+++ b/src/java.base/share/classes/java/lang/StringLatin1.java
@@ -109,12 +109,8 @@ final class StringLatin1 {
public static int compareTo(byte[] value, byte[] other, int len1, int len2) {
int lim = Math.min(len1, len2);
- for (int k = 0; k < lim; k++) {
- if (value[k] != other[k]) {
- return getChar(value, k) - getChar(other, k);
- }
- }
- return len1 - len2;
+ int k = ArraysSupport.mismatch(value, other, lim);
+ return (k < 0) ? len1 - len2 : getChar(value, k) - getChar(other, k);
}
@IntrinsicCandidate
diff --git a/test/micro/org/openjdk/bench/java/lang/StringBuilders.java b/test/micro/org/openjdk/bench/java/lang/StringBuilders.java
index e2a72a9ecb8..40f41659e7c 100644
--- a/test/micro/org/openjdk/bench/java/lang/StringBuilders.java
+++ b/test/micro/org/openjdk/bench/java/lang/StringBuilders.java
@@ -51,7 +51,9 @@ public class StringBuilders {
private String[] str3p9p8;
private String[] str22p40p31;
private StringBuilder sbLatin1;
+ private StringBuilder sbLatin2;
private StringBuilder sbUtf16;
+ private StringBuilder sbUtf17;
@Setup
public void setup() {
@@ -64,7 +66,9 @@ public class StringBuilders {
str3p9p8 = new String[]{"123", "123456789", "12345678"};
str22p40p31 = new String[]{"1234567890123456789012", "1234567890123456789012345678901234567890", "1234567890123456789012345678901"};
sbLatin1 = new StringBuilder("Latin1 string");
+ sbLatin2 = new StringBuilder("Latin1 string");
sbUtf16 = new StringBuilder("UTF-\uFF11\uFF16 string");
+ sbUtf17 = new StringBuilder("UTF-\uFF11\uFF16 string");
}
@Benchmark
@@ -250,6 +254,15 @@ public class StringBuilders {
return result.toString();
}
+ @Benchmark
+ public int compareToLatin1() {
+ return sbLatin1.compareTo(sbLatin2);
+ }
+
+ @Benchmark
+ public int compareToUTF16() {
+ return sbUtf16.compareTo(sbUtf17);
+ }
@Benchmark
public String toStringCharWithMixed8() {
diff --git a/test/micro/org/openjdk/bench/java/lang/StringComparisons.java b/test/micro/org/openjdk/bench/java/lang/StringComparisons.java
new file mode 100644
index 00000000000..b18b56bee2a
--- /dev/null
+++ b/test/micro/org/openjdk/bench/java/lang/StringComparisons.java
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2023, 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.lang;
+
+import org.openjdk.jmh.annotations.*;
+
+import java.util.concurrent.TimeUnit;
+
+/*
+ * This benchmark naively explores String::startsWith and other String
+ * comparison methods
+ */
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@State(Scope.Benchmark)
+@Warmup(iterations = 5, time = 1)
+@Measurement(iterations = 5, time = 1)
+@Fork(value = 3)
+public class StringComparisons {
+
+ @Param({"6", "15", "1024"})
+ public int size;
+
+ @Param({"true", "false"})
+ public boolean utf16;
+
+ public String string;
+ public String equalString;
+ public String endsWithA;
+ public String endsWithB;
+ public String startsWithA;
+
+ @Setup
+ public void setup() {
+ String c = utf16 ? "\uff11" : "c";
+ string = c.repeat(size);
+ equalString = c.repeat(size);
+ endsWithA = c.repeat(size).concat("A");
+ endsWithB = c.repeat(size).concat("B");
+ startsWithA = "A" + (c.repeat(size));
+ }
+
+ @Benchmark
+ public boolean startsWith() {
+ return endsWithA.startsWith(string);
+ }
+
+ @Benchmark
+ public boolean endsWith() {
+ return startsWithA.endsWith(string);
+ }
+
+ @Benchmark
+ public boolean regionMatches() {
+ return endsWithA.regionMatches(0, endsWithB, 0, endsWithB.length());
+ }
+
+ @Benchmark
+ public boolean regionMatchesRange() {
+ return startsWithA.regionMatches(1, endsWithB, 0, endsWithB.length() - 1);
+ }
+
+ @Benchmark
+ public boolean regionMatchesCI() {
+ return endsWithA.regionMatches(true, 0, endsWithB, 0, endsWithB.length());
+ }
+}
diff --git a/test/micro/org/openjdk/bench/java/lang/StringOther.java b/test/micro/org/openjdk/bench/java/lang/StringOther.java
index e6bee3f0376..99ebca8c3d1 100644
--- a/test/micro/org/openjdk/bench/java/lang/StringOther.java
+++ b/test/micro/org/openjdk/bench/java/lang/StringOther.java
@@ -49,17 +49,9 @@ public class StringOther {
private String testString;
private Random rnd;
- private String str1, str2, str3, str4;
- private String str1UP;
-
@Setup
public void setup() {
testString = "Idealism is what precedes experience; cynicism is what follows.";
- str1 = "vm-guld vm-guld vm-guld";
- str1UP = str1.toUpperCase(Locale.ROOT);
- str2 = "vm-guld vm-guld vm-guldx";
- str3 = "vm-guld vm-guld vm-guldx";
- str4 = "adadaskasdjierudks";
rnd = new Random();
}
@@ -70,15 +62,6 @@ public class StringOther {
}
}
- @Benchmark
- public int compareTo() {
- int total = 0;
- total += str1.compareTo(str2);
- total += str2.compareTo(str3);
- total += str3.compareTo(str4);
- return total;
- }
-
/**
* Creates (hopefully) unique Strings and internizes them, creating a zillion forgettable strings in the JVMs string
* pool.
@@ -94,10 +77,4 @@ public class StringOther {
return String.valueOf(rnd.nextInt()).intern();
}
- @Benchmark
- public void regionMatchesLatin1(Blackhole bh) {
- bh.consume(str1.regionMatches(true, 0, str2, 0, str1.length()));
- bh.consume(str2.regionMatches(true, 16, str1UP, 0, 8));
- bh.consume(str3.regionMatches(true, 6, str4, 1, 2));
- }
}