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implement lastIndexOf

This commit is contained in:
XenoAmess 2020-06-01 02:26:14 +08:00 committed by Rob Tompkins
parent dee8f6fb84
commit 217da1e6aa
2 changed files with 25 additions and 29 deletions
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31
src/main/java/org/apache/commons/lang3/CharSequenceUtils.java
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@ -266,22 +266,33 @@ public class CharSequenceUtils {
start = len1 - len2; start = len1 - len2;
} }
if (check(cs, searchChar, len2, start)) { char char0 = searchChar.charAt(0);
return start;
}
for (int i = start - 1; i >= 0; i--) { int i = start;
if (check(cs, searchChar, len2, i)) { while (true) {
while (cs.charAt(i) != char0) {
i--;
if (i < 0) {
return -1;
}
}
if (checkLaterThan1(cs, searchChar, len2, i)) {
return i; return i;
} else {
i--;
if (i < 0) {
return -1;
}
} }
} }
return -1;
} }
private static boolean check(final CharSequence cs, final CharSequence searchChar, int len2, int start1) { private static boolean checkLaterThan1(final CharSequence cs, final CharSequence searchChar, int len2, int start1) {
for (int i = 0; i < len2; i++) { for (int i = 1, j = len2 - 1; i <= j; i++, j--) {
if (cs.charAt(start1 + i) != searchChar.charAt(i)) { if (cs.charAt(start1 + i) != searchChar.charAt(i)
||
cs.charAt(start1 + j) != searchChar.charAt(j)
) {
return false; return false;
} }
} }

23
src/test/java/org/apache/commons/lang3/CharSequenceUtilsTest.java
View File

@ -16,23 +16,14 @@
*/ */
package org.apache.commons.lang3; package org.apache.commons.lang3;
import static java.nio.CharBuffer.wrap; import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import java.lang.reflect.Constructor; import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier; import java.lang.reflect.Modifier;
import java.nio.CharBuffer;
import java.util.Random; import java.util.Random;
import java.util.stream.IntStream; import java.util.stream.IntStream;
import org.apache.commons.lang3.text.StrBuilder; import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.Test;
/** /**
* Tests CharSequenceUtils * Tests CharSequenceUtils
@ -258,7 +249,7 @@ public class CharSequenceUtilsTest {
private void testNewLastIndexOfSingle(CharSequence a, CharSequence b) { private void testNewLastIndexOfSingle(CharSequence a, CharSequence b) {
int maxa = Math.max(a.length(), b.length()); int maxa = Math.max(a.length(), b.length());
for (int i = -maxa-10; i <= maxa+10; i++) { for (int i = -maxa - 10; i <= maxa + 10; i++) {
testNewLastIndexOfSingle(a, b, i); testNewLastIndexOfSingle(a, b, i);
} }
} }
@ -269,14 +260,8 @@ public class CharSequenceUtilsTest {
} }
private void testNewLastIndexOfSingleSingle(CharSequence a, CharSequence b, int start) { private void testNewLastIndexOfSingleSingle(CharSequence a, CharSequence b, int start) {
int expected = a.toString().lastIndexOf(b.toString(), start);
// assertEquals(
// expected,
// lastIndexOf(new WrapperString(a), b, start),
// "testNewLastIndexOf fails! original : " + a + " seg : " + b + " start : " + start
// );
assertEquals( assertEquals(
expected, a.toString().lastIndexOf(b.toString(), start),
CharSequenceUtils.lastIndexOf(new WrapperString(a.toString()), b.toString(), start), CharSequenceUtils.lastIndexOf(new WrapperString(a.toString()), b.toString(), start),
"testNewLastIndexOf fails! original : " + a + " seg : " + b + " start : " + start "testNewLastIndexOf fails! original : " + a + " seg : " + b + " start : " + start
); );