UTF8ByteArrayUtils.java
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上传日期:2018-01-08
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文件大小:3k
- /**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements. See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership. The ASF licenses this file
- * to you 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 org.apache.hadoop.util;
- public class UTF8ByteArrayUtils {
- /**
- * Find the first occurrence of the given byte b in a UTF-8 encoded string
- * @param utf a byte array containing a UTF-8 encoded string
- * @param start starting offset
- * @param end ending position
- * @param b the byte to find
- * @return position that first byte occures otherwise -1
- */
- public static int findByte(byte [] utf, int start, int end, byte b) {
- for(int i=start; i<end; i++) {
- if (utf[i]==b) {
- return i;
- }
- }
- return -1;
- }
- /**
- * Find the first occurrence of the given bytes b in a UTF-8 encoded string
- * @param utf a byte array containing a UTF-8 encoded string
- * @param start starting offset
- * @param end ending position
- * @param b the bytes to find
- * @return position that first byte occures otherwise -1
- */
- public static int findBytes(byte [] utf, int start, int end, byte[] b) {
- int matchEnd = end - b.length;
- for(int i=start; i<=matchEnd; i++) {
- boolean matched = true;
- for(int j=0; j<b.length; j++) {
- if (utf[i+j] != b[j]) {
- matched = false;
- break;
- }
- }
- if (matched) {
- return i;
- }
- }
- return -1;
- }
-
- /**
- * Find the nth occurrence of the given byte b in a UTF-8 encoded string
- * @param utf a byte array containing a UTF-8 encoded string
- * @param start starting offset
- * @param length the length of byte array
- * @param b the byte to find
- * @param n the desired occurrence of the given byte
- * @return position that nth occurrence of the given byte if exists; otherwise -1
- */
- public static int findNthByte(byte [] utf, int start, int length, byte b, int n) {
- int pos = -1;
- int nextStart = start;
- for (int i = 0; i < n; i++) {
- pos = findByte(utf, nextStart, length, b);
- if (pos < 0) {
- return pos;
- }
- nextStart = pos + 1;
- }
- return pos;
- }
-
- /**
- * Find the nth occurrence of the given byte b in a UTF-8 encoded string
- * @param utf a byte array containing a UTF-8 encoded string
- * @param b the byte to find
- * @param n the desired occurrence of the given byte
- * @return position that nth occurrence of the given byte if exists; otherwise -1
- */
- public static int findNthByte(byte [] utf, byte b, int n) {
- return findNthByte(utf, 0, utf.length, b, n);
- }
- }