diff options
| -rw-r--r-- | service/java/com/android/server/wifi/util/StringUtil.java | 48 | ||||
| -rw-r--r-- | tests/wifitests/src/com/android/server/wifi/util/StringUtilTest.java | 119 |
2 files changed, 167 insertions, 0 deletions
diff --git a/service/java/com/android/server/wifi/util/StringUtil.java b/service/java/com/android/server/wifi/util/StringUtil.java new file mode 100644 index 000000000..813b85b95 --- /dev/null +++ b/service/java/com/android/server/wifi/util/StringUtil.java @@ -0,0 +1,48 @@ +/* + * Copyright (C) 2016 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 com.android.server.wifi.util; + +/** Basic string utilities */ +public class StringUtil { + static final byte ASCII_PRINTABLE_MIN = ' '; + static final byte ASCII_PRINTABLE_MAX = '~'; + + /** Returns true if-and-only-if |byteArray| can be safely printed as ASCII. */ + public static boolean isAsciiPrintable(byte[] byteArray) { + if (byteArray == null) { + return true; + } + + for (byte b : byteArray) { + switch (b) { + // Control characters which actually are printable. Fall-throughs are deliberate. + case 0x07: // bell ('\a' not recognized in Java) + case '\f': // form feed + case '\n': // new line + case '\t': // horizontal tab + case 0x0b: // vertical tab ('\v' not recognized in Java) + continue; + } + + if (b < ASCII_PRINTABLE_MIN || b > ASCII_PRINTABLE_MAX) { + return false; + } + } + + return true; + } +} diff --git a/tests/wifitests/src/com/android/server/wifi/util/StringUtilTest.java b/tests/wifitests/src/com/android/server/wifi/util/StringUtilTest.java new file mode 100644 index 000000000..1ec69bd69 --- /dev/null +++ b/tests/wifitests/src/com/android/server/wifi/util/StringUtilTest.java @@ -0,0 +1,119 @@ +/* + * Copyright (C) 2016 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 com.android.server.wifi.util; + +import static org.junit.Assert.assertFalse; +import static org.junit.Assert.assertTrue; + +import android.test.suitebuilder.annotation.SmallTest; + +import org.junit.Test; + +/** + * Unit tests for {@link com.android.server.wifi.util.StringUtil}. + */ +@SmallTest +public class StringUtilTest { + static final byte ASCII_UNIT_SEPARATOR = 31; + static final byte ASCII_DEL = 127; + + /** Verifies that isAsciiPrintable() does not crash when passed a null array. */ + @Test + public void nullArrayDoesNotCauseCrash() { + assertTrue(StringUtil.isAsciiPrintable(null)); + } + + /** Verifies that isAsciiPrintable() considers an empty array to be printable. */ + @Test + public void emptyArrayIsPrintable() { + assertTrue(StringUtil.isAsciiPrintable(new byte[]{})); + } + + /** Verifies that isAsciiPrintable() considers a single printable byte to be printable. */ + @Test + public void arrayWithSinglePrintableByteIsPrintable() { + assertTrue(StringUtil.isAsciiPrintable(new byte[]{'a'})); + } + + /** + * Verifies that isAsciiPrintable() considers an array of multiple printable bytes to be + * printable. + */ + @Test + public void arrayWithMultiplePrintableBytesIsPrintable() { + assertTrue(StringUtil.isAsciiPrintable(new byte[]{'a', 'b'})); + } + + /** + * Verifies that isAsciiPrintable() considers bell, form feed, newline, horizontal tab, + * and vertical tab to be printable. + */ + @Test + public void printableControlCharactersAreConsideredPrintable() { + assertTrue(StringUtil.isAsciiPrintable(new byte[]{0x07})); // bell + assertTrue(StringUtil.isAsciiPrintable(new byte[]{'\f'})); // form feed + assertTrue(StringUtil.isAsciiPrintable(new byte[]{'\n'})); + assertTrue(StringUtil.isAsciiPrintable(new byte[]{'\t'})); + assertTrue(StringUtil.isAsciiPrintable(new byte[]{0x0b})); // vertical tab + } + + /** Verifies that isAsciiPrintable() considers a newline to be printable. */ + @Test + public void arrayWithNewlineIsPrintable() { + assertTrue(StringUtil.isAsciiPrintable(new byte[]{'\n'})); + } + + /** Verifies that isAsciiPrintable() considers a space to be printable. */ + @Test + public void arrayWithSpaceIsPrintable() { + assertTrue(StringUtil.isAsciiPrintable(new byte[]{' '})); + } + + /** Verifies that isAsciiPrintable() considers a tilde to be printable. */ + @Test + public void arrayWithTildeIsPrintable() { + assertTrue(StringUtil.isAsciiPrintable(new byte[]{'~'})); + } + + /** Verifies that isAsciiPrintable() considers a null to be unprintable. */ + @Test + public void arrayWithNullByteIsNotPrintable() { + assertFalse(StringUtil.isAsciiPrintable(new byte[]{0})); + } + + /** Verifies that isAsciiPrintable() considers (space-1) to be unprintable. */ + @Test + public void arrayWithUnitSeparatorIsNotPrintable() { + assertFalse(StringUtil.isAsciiPrintable(new byte[]{ASCII_UNIT_SEPARATOR})); + } + + /** Verifies that isAsciiPrintable() considers (tilde+1) to be unprintable. */ + @Test + public void arrayWithDelIsNotPrintable() { + assertFalse(StringUtil.isAsciiPrintable(new byte[]{ASCII_DEL})); + } + + /** + * Verifies that isAsciiPrintable() considers negative bytes to be unprintable. + * (In unsigned representation, these are values greater than DEL.) + */ + @Test + public void arrayWithNegativeByteIsNotPrintable() { + assertFalse(StringUtil.isAsciiPrintable(new byte[]{-128})); + assertFalse(StringUtil.isAsciiPrintable(new byte[]{-1})); + } +} |