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      1 /*
      2  * Copyright 2013, Google Inc.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are
      7  * met:
      8  *
      9  *     * Redistributions of source code must retain the above copyright
     10  * notice, this list of conditions and the following disclaimer.
     11  *     * Redistributions in binary form must reproduce the above
     12  * copyright notice, this list of conditions and the following disclaimer
     13  * in the documentation and/or other materials provided with the
     14  * distribution.
     15  *     * Neither the name of Google Inc. nor the names of its
     16  * contributors may be used to endorse or promote products derived from
     17  * this software without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 package org.jf.util;
     33 
     34 import javax.annotation.Nonnull;
     35 import javax.annotation.Nullable;
     36 
     37 public class StringWrapper {
     38     /**
     39      * Splits the given string into lines using on any embedded newlines, and wrapping the text as needed to conform to
     40      * the given maximum line width.
     41      *
     42      * This uses and assumes unix-style newlines
     43      *
     44      * @param str The string to split
     45      * @param maxWidth The maximum length of any line
     46      * @param output If given, try to use this array as the return value. If there are more values than will fit
     47      *               into the array, a new array will be allocated and returned, while the given array will be filled
     48      *               with as many lines as would fit.
     49      * @return The split lines from the original, as an array of Strings. The returned array may be larger than the
     50      *         number of lines. If this is the case, the end of the split lines will be denoted by a null entry in the
     51      *         array. If there is no null entry, then the size of the array exactly matches the number of lines.
     52      *         The returned lines will not contain an ending newline
     53      */
     54     public static String[] wrapString(@Nonnull String str, int maxWidth, @Nullable String[] output) {
     55         if (output == null) {
     56             output = new String[(int)((str.length() / maxWidth) * 1.5d + 1)];
     57         }
     58 
     59         int lineStart = 0;
     60         int arrayIndex = 0;
     61         int i;
     62         for (i=0; i<str.length(); i++) {
     63             char c = str.charAt(i);
     64 
     65             if (c == '\n') {
     66                 output = addString(output, str.substring(lineStart, i), arrayIndex++);
     67                 lineStart = i+1;
     68             } else if (i - lineStart == maxWidth) {
     69                 output = addString(output, str.substring(lineStart, i), arrayIndex++);
     70                 lineStart = i;
     71             }
     72         }
     73         if (lineStart != i || i == 0) {
     74             output = addString(output, str.substring(lineStart), arrayIndex++, output.length+1);
     75         }
     76 
     77         if (arrayIndex < output.length) {
     78             output[arrayIndex] = null;
     79         }
     80         return output;
     81     }
     82 
     83     private static String[] addString(@Nonnull String[] arr, String str, int index) {
     84         if (index >= arr.length) {
     85             arr = enlargeArray(arr, (int)(Math.ceil((arr.length + 1) * 1.5)));
     86         }
     87 
     88         arr[index] = str;
     89         return arr;
     90     }
     91 
     92     private static String[] addString(@Nonnull String[] arr, String str, int index, int newLength) {
     93         if (index >= arr.length) {
     94             arr = enlargeArray(arr, newLength);
     95         }
     96 
     97         arr[index] = str;
     98         return arr;
     99     }
    100 
    101     private static String[] enlargeArray(String[] arr, int newLength) {
    102         String[] newArr = new String[newLength];
    103         System.arraycopy(arr, 0, newArr, 0, arr.length);
    104         return newArr;
    105     }
    106 }
    107