Simple alternative to String.format(). (af7c5f95) · Commits · e / os / android_frameworks_base

apct-tests/perftests/core/src/android/text/TextUtilsPerfTest.java

0 → 100644

+109 −0

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		/*
		* Copyright (C) 2020 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package android.text;

		import android.perftests.utils.BenchmarkState;
		import android.perftests.utils.PerfStatusReporter;

		import androidx.test.filters.LargeTest;
		import androidx.test.runner.AndroidJUnit4;

		import org.junit.Rule;
		import org.junit.Test;
		import org.junit.runner.RunWith;

		import java.util.function.Supplier;

		@RunWith(AndroidJUnit4.class)
		@LargeTest
		public class TextUtilsPerfTest {
		@Rule
		public PerfStatusReporter mPerfStatusReporter = new PerfStatusReporter();

		public static final String TEMPLATE = "Template that combines %s and %d together";

		public String mVar1 = "example";
		public int mVar2 = 42;

		/**
		* Measure overhead of formatting a string via {@link String#format}.
		*/
		@Test
		public void timeFormatUpstream() {
		final BenchmarkState state = mPerfStatusReporter.getBenchmarkState();
		while (state.keepRunning()) {
		String res = String.format(TEMPLATE, mVar1, mVar2);
		}
		}

		/**
		* Measure overhead of formatting a string via
		* {@link TextUtils#formatSimple}.
		*/
		@Test
		public void timeFormatLocal() {
		final BenchmarkState state = mPerfStatusReporter.getBenchmarkState();
		while (state.keepRunning()) {
		String res = TextUtils.formatSimple(TEMPLATE, mVar1, mVar2);
		}
		}

		/**
		* Measure overhead of formatting a string inline.
		*/
		@Test
		public void timeFormatInline() {
		final BenchmarkState state = mPerfStatusReporter.getBenchmarkState();
		while (state.keepRunning()) {
		String res = "Template that combines " + mVar1 + " and " + mVar2 + " together";
		}
		}

		/**
		* Measure overhead of a passing null-check that uses a lambda to
		* communicate a custom error message.
		*/
		@Test
		public void timeFormat_Skip_Lambda() {
		final BenchmarkState state = mPerfStatusReporter.getBenchmarkState();
		while (state.keepRunning()) {
		requireNonNull(this, () -> {
		return String.format(TEMPLATE, mVar1, mVar2);
		});
		}
		}

		/**
		* Measure overhead of a passing null-check that uses varargs to communicate
		* a custom error message.
		*/
		@Test
		public void timeFormat_Skip_Varargs() {
		final BenchmarkState state = mPerfStatusReporter.getBenchmarkState();
		while (state.keepRunning()) {
		requireNonNull(this, TEMPLATE, mVar1, mVar2);
		}
		}

		private static <T> T requireNonNull(T obj, Supplier<String> messageSupplier) {
		return obj;
		}

		private static <T> T requireNonNull(T obj, String format, Object... args) {
		return obj;
		}
		}

core/java/android/text/TextUtils.java

+88 −0

Original line number	Diff line number	Diff line
		@@ -2079,6 +2079,94 @@ public class TextUtils {
		return Resources.getSystem().getQuantityString(R.plurals.selected_count, count, count);
		}

		/**
		* Simple alternative to {@link String#format} which purposefully supports
		* only a small handful of substitutions to improve execution speed.
		* Benchmarking reveals this optimized alternative performs 6.5x faster for
		* a typical format string.
		* <p>
		* Below is a summary of the limited grammar supported by this method; if
		* you need advanced features, please continue using {@link String#format}.
		* <ul>
		* <li>{@code %b} for {@code boolean}
		* <li>{@code %c} for {@code char}
		* <li>{@code %d} for {@code int} or {@code long}
		* <li>{@code %f} for {@code float} or {@code double}
		* <li>{@code %s} for {@code String}
		* <li>{@code %x} for hex representation of {@code int} or {@code long}
		* <li>{@code %%} for literal {@code %}
		* </ul>
		*
		* @throws IllegalArgumentException if the format string or arguments don't
		* match the supported grammar described above.
		* @hide
		*/
		public static @NonNull String formatSimple(@NonNull String format, Object... args) {
		final StringBuilder sb = new StringBuilder(format);
		int j = 0;
		for (int i = 0; i < sb.length(); ) {
		if (sb.charAt(i) == '%') {
		final String repl;
		final char code = sb.charAt(i + 1);
		switch (code) {
		case 'b': {
		if (j == args.length) {
		throw new IllegalArgumentException("Too few arguments");
		}
		final Object arg = args[j++];
		if (arg instanceof Boolean) {
		repl = Boolean.toString((boolean) arg);
		} else {
		repl = Boolean.toString(arg != null);
		}
		break;
		}
		case 'c':
		case 'd':
		case 'f':
		case 's': {
		if (j == args.length) {
		throw new IllegalArgumentException("Too few arguments");
		}
		final Object arg = args[j++];
		repl = String.valueOf(arg);
		break;
		}
		case 'x': {
		if (j == args.length) {
		throw new IllegalArgumentException("Too few arguments");
		}
		final Object arg = args[j++];
		if (arg instanceof Integer) {
		repl = Integer.toHexString((int) arg);
		} else if (arg instanceof Long) {
		repl = Long.toHexString((long) arg);
		} else {
		throw new IllegalArgumentException(
		"Unsupported hex type " + arg.getClass());
		}
		break;
		}
		case '%': {
		repl = "%";
		break;
		}
		default: {
		throw new IllegalArgumentException("Unsupported format code " + code);
		}
		}
		sb.replace(i, i + 2, repl);
		i += repl.length();
		} else {
		i++;
		}
		}
		if (j != args.length) {
		throw new IllegalArgumentException("Too many arguments");
		}
		return sb.toString();
		}

		/**
		* Returns whether or not the specified spanned text has a style span.
		* @hide

core/java/com/android/internal/util/Preconditions.java

+57 −9

Original line number	Diff line number	Diff line
		@@ -31,6 +31,12 @@ import java.util.Objects;
		*/
		public class Preconditions {

		/**
		* Ensures that an expression checking an argument is true.
		*
		* @param expression the expression to check
		* @throws IllegalArgumentException if {@code expression} is false
		*/
		@UnsupportedAppUsage
		public static void checkArgument(boolean expression) {
		if (!expression) {
		@@ -62,8 +68,9 @@ public class Preconditions {
		* @param messageArgs arguments for {@code messageTemplate}
		* @throws IllegalArgumentException if {@code expression} is false
		*/
		public static void checkArgument(boolean expression,
		final String messageTemplate,
		public static void checkArgument(
		final boolean expression,
		final @NonNull String messageTemplate,
		final Object... messageArgs) {
		if (!expression) {
		throw new IllegalArgumentException(String.format(messageTemplate, messageArgs));
		@@ -114,7 +121,9 @@ public class Preconditions {
		* @throws IllegalArgumentException if {@code string} is empty
		*/
		public static @NonNull <T extends CharSequence> T checkStringNotEmpty(
		final T string, final String messageTemplate, final Object... messageArgs) {
		final T string,
		final @NonNull String messageTemplate,
		final Object... messageArgs) {
		if (TextUtils.isEmpty(string)) {
		throw new IllegalArgumentException(String.format(messageTemplate, messageArgs));
		}
		@@ -159,18 +168,50 @@ public class Preconditions {
		return reference;
		}

		/**
		* Ensures that an object reference passed as a parameter to the calling
		* method is not null.
		*
		* @param messageTemplate a printf-style message template to use if the check fails; will
		* be converted to a string using {@link String#format(String, Object...)}
		* @param messageArgs arguments for {@code messageTemplate}
		* @throws NullPointerException if {@code reference} is null
		*/
		public static @NonNull <T> T checkNotNull(
		final T reference,
		final @NonNull String messageTemplate,
		final Object... messageArgs) {
		if (reference == null) {
		throw new NullPointerException(String.format(messageTemplate, messageArgs));
		}
		return reference;
		}

		/**
		* Ensures the truth of an expression involving the state of the calling
		* instance, but not involving any parameters to the calling method.
		*
		* @param expression a boolean expression
		* @param message exception message
		* @throws IllegalStateException if {@code expression} is false
		*/
		@UnsupportedAppUsage
		public static void checkState(final boolean expression, String message) {
		public static void checkState(final boolean expression) {
		checkState(expression, null);
		}

		/**
		* Ensures the truth of an expression involving the state of the calling
		* instance, but not involving any parameters to the calling method.
		*
		* @param expression a boolean expression
		* @param errorMessage the exception message to use if the check fails; will
		* be converted to a string using {@link String#valueOf(Object)}
		* @throws IllegalStateException if {@code expression} is false
		*/
		@UnsupportedAppUsage
		public static void checkState(final boolean expression, String errorMessage) {
		if (!expression) {
		throw new IllegalStateException(message);
		throw new IllegalStateException(errorMessage);
		}
		}

		@@ -179,11 +220,18 @@ public class Preconditions {
		* instance, but not involving any parameters to the calling method.
		*
		* @param expression a boolean expression
		* @param messageTemplate a printf-style message template to use if the check fails; will
		* be converted to a string using {@link String#format(String, Object...)}
		* @param messageArgs arguments for {@code messageTemplate}
		* @throws IllegalStateException if {@code expression} is false
		*/
		@UnsupportedAppUsage
		public static void checkState(final boolean expression) {
		checkState(expression, null);
		public static void checkState(
		final boolean expression,
		final @NonNull String messageTemplate,
		final Object... messageArgs) {
		if (!expression) {
		throw new IllegalStateException(String.format(messageTemplate, messageArgs));
		}
		}

		/**

core/tests/coretests/src/android/text/TextUtilsTest.java

+51 −0

Original line number	Diff line number	Diff line
		@@ -16,6 +16,8 @@

		package android.text;

		import static android.text.TextUtils.formatSimple;

		import static org.junit.Assert.assertEquals;
		import static org.junit.Assert.assertFalse;
		import static org.junit.Assert.assertNotNull;
		@@ -793,4 +795,53 @@ public class TextUtilsTest {
		assertEquals("ABC", TextUtils.trimToLengthWithEllipsis("ABC", 3));
		assertEquals("", TextUtils.trimToLengthWithEllipsis("", 3));
		}

		@Test
		public void testFormatSimple_Types() {
		assertEquals("true", formatSimple("%b", true));
		assertEquals("false", formatSimple("%b", false));
		assertEquals("true", formatSimple("%b", this));
		assertEquals("false", formatSimple("%b", new Object[] { null }));

		assertEquals("!", formatSimple("%c", '!'));

		assertEquals("42", formatSimple("%d", 42));
		assertEquals("281474976710656", formatSimple("%d", 281474976710656L));

		assertEquals("3.14159", formatSimple("%f", 3.14159));
		assertEquals("NaN", formatSimple("%f", Float.NaN));

		assertEquals("example", formatSimple("%s", "example"));
		assertEquals("null", formatSimple("%s", new Object[] { null }));

		assertEquals("2a", formatSimple("%x", 42));
		assertEquals("1000000000000", formatSimple("%x", 281474976710656L));

		assertEquals("%", formatSimple("%%"));
		}

		@Test
		public void testFormatSimple_Empty() {
		assertEquals("", formatSimple(""));
		}

		@Test
		public void testFormatSimple_Typical() {
		assertEquals("String foobar and %% number -42 together",
		formatSimple("String %s%s and %%%% number %d%d together", "foo", "bar", -4, 2));
		}

		@Test
		public void testFormatSimple_Mismatch() {
		try {
		formatSimple("%s");
		fail();
		} catch (IllegalArgumentException expected) {
		}
		try {
		formatSimple("%s", "foo", "bar");
		fail();
		} catch (IllegalArgumentException expected) {
		}
		}
		}