118 lines
3.5 KiB
Java
118 lines
3.5 KiB
Java
/*
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* Copyright 2011 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.util.internal;
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import java.util.Formatter;
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/**
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* String utility class.
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*/
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public final class StringUtil {
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private StringUtil() {
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// Unused.
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}
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public static final String NEWLINE;
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static {
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String newLine = null;
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try {
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newLine = new Formatter().format("%n").toString();
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} catch (Exception e) {
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newLine = "\n";
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}
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NEWLINE = newLine;
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}
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/**
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* Strip an Object of it's ISO control characters.
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*
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* @param value
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* The Object that should be stripped. This objects toString method will
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* called and the result passed to {@link #stripControlCharacters(String)}.
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* @return {@code String}
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* A new String instance with its hexadecimal control characters replaced
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* by a space. Or the unmodified String if it does not contain any ISO
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* control characters.
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*/
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public static String stripControlCharacters(Object value) {
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if (value == null) {
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return null;
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}
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return stripControlCharacters(value.toString());
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}
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/**
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* Strip a String of it's ISO control characters.
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*
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* @param value
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* The String that should be stripped.
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* @return {@code String}
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* A new String instance with its hexadecimal control characters replaced
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* by a space. Or the unmodified String if it does not contain any ISO
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* control characters.
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*/
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public static String stripControlCharacters(String value) {
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if (value == null) {
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return null;
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}
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boolean hasControlChars = false;
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for (int i = value.length() - 1; i >= 0; i --) {
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if (Character.isISOControl(value.charAt(i))) {
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hasControlChars = true;
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break;
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}
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}
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if (!hasControlChars) {
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return value;
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}
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StringBuilder buf = new StringBuilder(value.length());
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int i = 0;
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// Skip initial control characters (i.e. left trim)
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for (; i < value.length(); i ++) {
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if (!Character.isISOControl(value.charAt(i))) {
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break;
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}
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}
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// Copy non control characters and substitute control characters with
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// a space. The last control characters are trimmed.
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boolean suppressingControlChars = false;
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for (; i < value.length(); i ++) {
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if (Character.isISOControl(value.charAt(i))) {
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suppressingControlChars = true;
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continue;
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} else {
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if (suppressingControlChars) {
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suppressingControlChars = false;
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buf.append(' ');
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}
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buf.append(value.charAt(i));
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}
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}
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return buf.toString();
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}
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}
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