/*******************************************************************************
* Copyright (c) 2009, 2010 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.equinox.p2.internal.repository.comparator.java;
public final class CharOperation {
public static final char[] This = "this".toCharArray(); //$NON-NLS-1$
public static final char[] JAVA_LANG_ANNOTATION_DOCUMENTED = "Ljava/lang/annotation/Documented;".toCharArray(); //$NON-NLS-1$
public static final char[] JAVA_LANG_ANNOTATION_ELEMENTTYPE = "Ljava/lang/annotation/ElementType;".toCharArray(); //$NON-NLS-1$
public static final char[] JAVA_LANG_ANNOTATION_RETENTION = "Ljava/lang/annotation/Retention;".toCharArray(); //$NON-NLS-1$
public static final char[] JAVA_LANG_ANNOTATION_RETENTIONPOLICY = "Ljava/lang/annotation/RetentionPolicy;".toCharArray(); //$NON-NLS-1$
public static final char[] JAVA_LANG_ANNOTATION_TARGET = "Ljava/lang/annotation/Target;".toCharArray(); //$NON-NLS-1$
public static final char[] JAVA_LANG_DEPRECATED = "Ljava/lang/Deprecated;".toCharArray(); //$NON-NLS-1$
public static final char[] JAVA_LANG_ANNOTATION_INHERITED = "Ljava/lang/annotation/Inherited;".toCharArray(); //$NON-NLS-1$
/**
* Constant for an empty char array
*/
public static final char[] NO_CHAR = new char[0];
/**
* Constant for an empty char array with two dimensions.
*/
public static final char[][] NO_CHAR_CHAR = new char[0][];
/**
* Answers a hashcode for the array
*
* @param array the array for which a hashcode is required
* @return the hashcode
* @throws NullPointerException if array is null
*/
public static final int hashCode(char[] array) {
int length = array.length;
int hash = length == 0 ? 31 : array[0];
if (length < 8) {
for (int i = length; --i > 0;)
hash = (hash * 31) + array[i];
} else {
// 8 characters is enough to compute a decent hash code, don't waste time examining every character
for (int i = length - 1, last = i > 16 ? i - 16 : 0; i > last; i -= 2)
hash = (hash * 31) + array[i];
}
return hash & 0x7FFFFFFF;
}
/**
* Answers the last index in the array for which the corresponding character is
* equal to toBeFound starting from the end of the array.
* Answers -1 if no occurrence of this character is found.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* toBeFound = 'c'
* array = { ' a', 'b', 'c', 'd' , 'c', 'e' }
* result => 4
* </pre>
* </li>
* <li><pre>
* toBeFound = 'e'
* array = { ' a', 'b', 'c', 'd' }
* result => -1
* </pre>
* </li>
* </ol>
*
* @param toBeFound the character to search
* @param array the array to be searched
* @return the last index in the array for which the corresponding character is
* equal to toBeFound starting from the end of the array, -1 otherwise
* @throws NullPointerException if array is null
*/
public static final int lastIndexOf(char toBeFound, char[] array) {
for (int i = array.length; --i >= 0;)
if (toBeFound == array[i])
return i;
return -1;
}
/**
* Return a new array which is the split of the given array using the given divider.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* divider = 'b'
* array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
* result => { { 'a' }, { }, { 'a' }, { 'a' } }
* </pre>
* </li>
* <li><pre>
* divider = 'c'
* array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
* result => { { 'a', 'b', 'b', 'a', 'b', 'a' } }
* </pre>
* </li>
* <li><pre>
* divider = 'c'
* array = { ' ', ' ', 'a' , 'b', 'b', 'a', 'b', 'a', ' ' }
* result => { { ' ', 'a', 'b', 'b', 'a', 'b', 'a', ' ' } }
* </pre>
* </li>
* </ol>
*
* @param divider the given divider
* @param array the given array
* @return a new array which is the split of the given array using the given divider
*/
public static final char[][] splitOn(char divider, char[] array) {
int length = array == null ? 0 : array.length;
if (length == 0)
return NO_CHAR_CHAR;
int wordCount = 1;
for (int i = 0; i < length; i++)
if (array[i] == divider)
wordCount++;
char[][] split = new char[wordCount][];
int last = 0, currentWord = 0;
for (int i = 0; i < length; i++) {
if (array[i] == divider) {
split[currentWord] = new char[i - last];
System.arraycopy(array, last, split[currentWord++], 0, i - last);
last = i + 1;
}
}
split[currentWord] = new char[length - last];
System.arraycopy(array, last, split[currentWord], 0, length - last);
return split;
}
/**
* Answers the first index in the array for which the corresponding character is
* equal to toBeFound starting the search at index start.
* Answers -1 if no occurrence of this character is found.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* toBeFound = 'c'
* array = { ' a', 'b', 'c', 'd' }
* start = 2
* result => 2
* </pre>
* </li>
* <li><pre>
* toBeFound = 'c'
* array = { ' a', 'b', 'c', 'd' }
* start = 3
* result => -1
* </pre>
* </li>
* <li><pre>
* toBeFound = 'e'
* array = { ' a', 'b', 'c', 'd' }
* start = 1
* result => -1
* </pre>
* </li>
* </ol>
*
* @param toBeFound the character to search
* @param array the array to be searched
* @param start the starting index
* @return the first index in the array for which the corresponding character is
* equal to toBeFound, -1 otherwise
* @throws NullPointerException if array is null
* @throws ArrayIndexOutOfBoundsException if start is lower than 0
*/
public static final int indexOf(char toBeFound, char[] array, int start) {
for (int i = start; i < array.length; i++)
if (toBeFound == array[i])
return i;
return -1;
}
/**
* Answers a new array with prepending the prefix character and appending the suffix
* character at the end of the array. If array is null, it answers a new array containing the
* prefix and the suffix characters.
* <br>
* <br>
* For example:<br>
* <ol>
* <li><pre>
* prefix = 'a'
* array = { 'b' }
* suffix = 'c'
* => result = { 'a', 'b' , 'c' }
* </pre>
* </li>
* <li><pre>
* prefix = 'a'
* array = null
* suffix = 'c'
* => result = { 'a', 'c' }
* </pre></li>
* </ol>
*
* @param prefix the prefix character
* @param array the array that is concatenated with the prefix and suffix characters
* @param suffix the suffix character
* @return the new array
*/
public static final char[] concat(char prefix, char[] array, char suffix) {
if (array == null)
return new char[] {prefix, suffix};
int length = array.length;
char[] result = new char[length + 2];
result[0] = prefix;
System.arraycopy(array, 0, result, 1, length);
result[length + 1] = suffix;
return result;
}
/**
* Answers the concatenation of the three arrays. It answers null if the three arrays are null.
* If first is null, it answers the concatenation of second and third.
* If second is null, it answers the concatenation of first and third.
* If third is null, it answers the concatenation of first and second.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* first = null
* second = { 'a' }
* third = { 'b' }
* => result = { ' a', 'b' }
* </pre>
* </li>
* <li><pre>
* first = { 'a' }
* second = null
* third = { 'b' }
* => result = { ' a', 'b' }
* </pre>
* </li>
* <li><pre>
* first = { 'a' }
* second = { 'b' }
* third = null
* => result = { ' a', 'b' }
* </pre>
* </li>
* <li><pre>
* first = null
* second = null
* third = null
* => result = null
* </pre>
* </li>
* <li><pre>
* first = { 'a' }
* second = { 'b' }
* third = { 'c' }
* => result = { 'a', 'b', 'c' }
* </pre>
* </li>
* </ol>
*
* @param first the first array to concatenate
* @param second the second array to concatenate
* @param third the third array to concatenate
*
* @return the concatenation of the three arrays, or null if the three arrays are null.
*/
public static final char[] concat(char[] first, char[] second, char[] third) {
if (first == null)
return concat(second, third);
if (second == null)
return concat(first, third);
if (third == null)
return concat(first, second);
int length1 = first.length;
int length2 = second.length;
int length3 = third.length;
char[] result = new char[length1 + length2 + length3];
System.arraycopy(first, 0, result, 0, length1);
System.arraycopy(second, 0, result, length1, length2);
System.arraycopy(third, 0, result, length1 + length2, length3);
return result;
}
/**
* Answers the concatenation of the two arrays. It answers null if the two arrays are null.
* If the first array is null, then the second array is returned.
* If the second array is null, then the first array is returned.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* first = null
* second = { 'a' }
* => result = { ' a' }
* </pre>
* </li>
* <li><pre>
* first = { ' a' }
* second = null
* => result = { ' a' }
* </pre>
* </li>
* <li><pre>
* first = { ' a' }
* second = { ' b' }
* => result = { ' a' , ' b' }
* </pre>
* </li>
* </ol>
*
* @param first the first array to concatenate
* @param second the second array to concatenate
* @return the concatenation of the two arrays, or null if the two arrays are null.
*/
public static final char[] concat(char[] first, char[] second) {
if (first == null)
return second;
if (second == null)
return first;
int length1 = first.length;
int length2 = second.length;
char[] result = new char[length1 + length2];
System.arraycopy(first, 0, result, 0, length1);
System.arraycopy(second, 0, result, length1, length2);
return result;
}
/**
* Replace all occurrence of the character to be replaced with the replacement character in the
* given array.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
* toBeReplaced = 'b'
* replacementChar = 'a'
* result => No returned value, but array is now equals to { 'a' , 'a', 'a', 'a', 'a', 'a' }
* </pre>
* </li>
* <li><pre>
* array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
* toBeReplaced = 'c'
* replacementChar = 'a'
* result => No returned value, but array is now equals to { 'a' , 'b', 'b', 'a', 'b', 'a' }
* </pre>
* </li>
* </ol>
*
* @param array the given array
* @param toBeReplaced the character to be replaced
* @param replacementChar the replacement character
* @throws NullPointerException if the given array is null
*/
public static final void replace(char[] array, char toBeReplaced, char replacementChar) {
if (toBeReplaced != replacementChar) {
for (int i = 0, max = array.length; i < max; i++) {
if (array[i] == toBeReplaced)
array[i] = replacementChar;
}
}
}
/**
* Replace all occurrence of the character to be replaced with the replacement character
* in a copy of the given array. Returns the given array if no occurrences of the character
* to be replaced are found.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
* toBeReplaced = 'b'
* replacementChar = 'a'
* result => A new array that is equals to { 'a' , 'a', 'a', 'a', 'a', 'a' }
* </pre>
* </li>
* <li><pre>
* array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
* toBeReplaced = 'c'
* replacementChar = 'a'
* result => The original array that remains unchanged.
* </pre>
* </li>
* </ol>
*
* @param array the given array
* @param toBeReplaced the character to be replaced
* @param replacementChar the replacement character
* @throws NullPointerException if the given array is null
* @since 3.1
*/
public static final char[] replaceOnCopy(char[] array, char toBeReplaced, char replacementChar) {
char[] result = null;
for (int i = 0, length = array.length; i < length; i++) {
char c = array[i];
if (c == toBeReplaced) {
if (result == null) {
result = new char[length];
System.arraycopy(array, 0, result, 0, i);
}
result[i] = replacementChar;
} else if (result != null) {
result[i] = c;
}
}
if (result == null)
return array;
return result;
}
/**
* Answers the first index in the array for which the corresponding character is
* equal to toBeFound. Answers -1 if no occurrence of this character is found.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* toBeFound = 'c'
* array = { ' a', 'b', 'c', 'd' }
* result => 2
* </pre>
* </li>
* <li><pre>
* toBeFound = 'e'
* array = { ' a', 'b', 'c', 'd' }
* result => -1
* </pre>
* </li>
* </ol>
*
* @param toBeFound the character to search
* @param array the array to be searched
* @return the first index in the array for which the corresponding character is
* equal to toBeFound, -1 otherwise
* @throws NullPointerException if array is null
*/
public static final int indexOf(char toBeFound, char[] array) {
return indexOf(toBeFound, array, 0);
}
/**
* Answers a new array which is a copy of the given array starting at the given start and
* ending at the given end. The given start is inclusive and the given end is exclusive.
* Answers null if start is greater than end, if start is lower than 0 or if end is greater
* than the length of the given array. If end equals -1, it is converted to the array length.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* array = { 'a' , 'b' }
* start = 0
* end = 1
* result => { 'a' }
* </pre>
* </li>
* <li><pre>
* array = { 'a', 'b' }
* start = 0
* end = -1
* result => { 'a' , 'b' }
* </pre>
* </li>
* </ol>
*
* @param array the given array
* @param start the given starting index
* @param end the given ending index
* @return a new array which is a copy of the given array starting at the given start and
* ending at the given end
* @throws NullPointerException if the given array is null
*/
public static final char[] subarray(char[] array, int start, int end) {
if (end == -1)
end = array.length;
if (start > end)
return null;
if (start < 0)
return null;
if (end > array.length)
return null;
char[] result = new char[end - start];
System.arraycopy(array, start, result, 0, end - start);
return result;
}
/**
* Answers a new array which is a copy of the given array starting at the given start and
* ending at the given end. The given start is inclusive and the given end is exclusive.
* Answers null if start is greater than end, if start is lower than 0 or if end is greater
* than the length of the given array. If end equals -1, it is converted to the array length.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* array = { { 'a' } , { 'b' } }
* start = 0
* end = 1
* result => { { 'a' } }
* </pre>
* </li>
* <li><pre>
* array = { { 'a' } , { 'b' } }
* start = 0
* end = -1
* result => { { 'a' }, { 'b' } }
* </pre>
* </li>
* </ol>
*
* @param array the given array
* @param start the given starting index
* @param end the given ending index
* @return a new array which is a copy of the given array starting at the given start and
* ending at the given end
* @throws NullPointerException if the given array is null
*/
public static final char[][] subarray(char[][] array, int start, int end) {
if (end == -1)
end = array.length;
if (start > end)
return null;
if (start < 0)
return null;
if (end > array.length)
return null;
char[][] result = new char[end - start][];
System.arraycopy(array, start, result, 0, end - start);
return result;
}
/**
* Return a new array which is the split of the given array using the given divider. The given end
* is exclusive and the given start is inclusive.
* <br>
* <br>
* For example:
* <ol>
* <li><pre>
* divider = 'b'
* array = { 'a' , 'b', 'b', 'a', 'b', 'a' }
* start = 2
* end = 5
* result => { { }, { 'a' }, { } }
* </pre>
* </li>
* </ol>
*
* @param divider the given divider
* @param array the given array
* @param start the given starting index
* @param end the given ending index
* @return a new array which is the split of the given array using the given divider
* @throws ArrayIndexOutOfBoundsException if start is lower than 0 or end is greater than the array length
*/
public static final char[][] splitOn(char divider, char[] array, int start, int end) {
int length = array == null ? 0 : array.length;
if (length == 0 || start > end)
return NO_CHAR_CHAR;
int wordCount = 1;
for (int i = start; i < end; i++)
if (array[i] == divider)
wordCount++;
char[][] split = new char[wordCount][];
int last = start, currentWord = 0;
for (int i = start; i < end; i++) {
if (array[i] == divider) {
split[currentWord] = new char[i - last];
System.arraycopy(array, last, split[currentWord++], 0, i - last);
last = i + 1;
}
}
split[currentWord] = new char[end - last];
System.arraycopy(array, last, split[currentWord], 0, end - last);
return split;
}
}