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/*
* Copyright (C) 2007 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.internal.util;
/**
* {@link CharSequence} utility methods.
*/
public class CharSequences {
/**
* Adapts {@link CharSequence} to an array of ASCII (7-bits per character)
* bytes.
*
* @param bytes ASCII bytes
*/
public static CharSequence forAsciiBytes(final byte[] bytes) {
return new CharSequence() {
public char charAt(int index) {
return (char) bytes[index];
}
public int length() {
return bytes.length;
}
public CharSequence subSequence(int start, int end) {
return forAsciiBytes(bytes, start, end);
}
public String toString() {
return new String(bytes);
}
};
}
/**
* Adapts {@link CharSequence} to an array of ASCII (7-bits per character)
* bytes.
*
* @param bytes ASCII bytes
* @param start index, inclusive
* @param end index, exclusive
*
* @throws IndexOutOfBoundsException if start or end are negative, if end
* is greater than length(), or if start is greater than end
*/
public static CharSequence forAsciiBytes(final byte[] bytes,
final int start, final int end) {
validate(start, end, bytes.length);
return new CharSequence() {
public char charAt(int index) {
return (char) bytes[index + start];
}
public int length() {
return end - start;
}
public CharSequence subSequence(int newStart, int newEnd) {
newStart -= start;
newEnd -= start;
validate(newStart, newEnd, length());
return forAsciiBytes(bytes, newStart, newEnd);
}
public String toString() {
return new String(bytes, start, length());
}
};
}
static void validate(int start, int end, int length) {
if (start < 0) throw new IndexOutOfBoundsException();
if (end < 0) throw new IndexOutOfBoundsException();
if (end > length) throw new IndexOutOfBoundsException();
if (start > end) throw new IndexOutOfBoundsException();
}
/**
* Compares two character sequences for equality.
*/
public static boolean equals(CharSequence a, CharSequence b) {
if (a.length() != b.length()) {
return false;
}
int length = a.length();
for (int i = 0; i < length; i++) {
if (a.charAt(i) != b.charAt(i)) {
return false;
}
}
return true;
}
/**
* Compares two character sequences with API like {@link Comparable#compareTo}.
*
* @param me The CharSequence that receives the compareTo call.
* @param another The other CharSequence.
* @return See {@link Comparable#compareTo}.
*/
public static int compareToIgnoreCase(CharSequence me, CharSequence another) {
// Code adapted from String#compareTo
int myLen = me.length(), anotherLen = another.length();
int myPos = 0, anotherPos = 0, result;
int end = (myLen < anotherLen) ? myLen : anotherLen;
while (myPos < end) {
if ((result = Character.toLowerCase(me.charAt(myPos++))
- Character.toLowerCase(another.charAt(anotherPos++))) != 0) {
return result;
}
}
return myLen - anotherLen;
}
}
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