1/* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17/* 18 * As per the Apache license requirements, this file has been modified 19 * from its original state. 20 * 21 * Such modifications are Copyright (C) 2010 Ben Gruver, and are released 22 * under the original license 23 */ 24 25package org.jf.dexlib.Util; 26 27import java.io.FilterWriter; 28import java.io.IOException; 29import java.io.Writer; 30 31/** 32 * Writer that wraps another writer and passes width-limited and 33 * optionally-prefixed output to its subordinate. When lines are 34 * wrapped they are automatically indented based on the start of the 35 * line. 36 */ 37public final class IndentingWriter extends FilterWriter { 38 /** null-ok; optional prefix for every line */ 39 private final String prefix; 40 41 /** > 0; the maximum output width */ 42 private final int width; 43 44 /** > 0; the maximum indent */ 45 private final int maxIndent; 46 47 /** >= 0; current output column (zero-based) */ 48 private int column; 49 50 /** whether indent spaces are currently being collected */ 51 private boolean collectingIndent; 52 53 /** >= 0; current indent amount */ 54 private int indent; 55 56 /** 57 * Constructs an instance. 58 * 59 * @param out non-null; writer to send final output to 60 * @param width >= 0; the maximum output width (not including 61 * <code>prefix</code>), or <code>0</code> for no maximum 62 * @param prefix non-null; the prefix for each line 63 */ 64 public IndentingWriter(Writer out, int width, String prefix) { 65 super(out); 66 67 if (out == null) { 68 throw new NullPointerException("out == null"); 69 } 70 71 if (width < 0) { 72 throw new IllegalArgumentException("width < 0"); 73 } 74 75 if (prefix == null) { 76 throw new NullPointerException("prefix == null"); 77 } 78 79 this.width = (width != 0) ? width : Integer.MAX_VALUE; 80 this.maxIndent = width >> 1; 81 this.prefix = (prefix.length() == 0) ? null : prefix; 82 83 bol(); 84 } 85 86 /** 87 * Constructs a no-prefix instance. 88 * 89 * @param out non-null; writer to send final output to 90 * @param width >= 0; the maximum output width (not including 91 * <code>prefix</code>), or <code>0</code> for no maximum 92 */ 93 public IndentingWriter(Writer out, int width) { 94 this(out, width, ""); 95 } 96 97 /** {@inheritDoc} */ 98 @Override 99 public void write(int c) throws IOException { 100 synchronized (lock) { 101 if (collectingIndent) { 102 if (c == ' ') { 103 indent++; 104 if (indent >= maxIndent) { 105 indent = maxIndent; 106 collectingIndent = false; 107 } 108 } else { 109 collectingIndent = false; 110 } 111 } 112 113 if ((column == width) && (c != '\n')) { 114 out.write('\n'); 115 column = 0; 116 /* 117 * Note: No else, so this should fall through to the next 118 * if statement. 119 */ 120 } 121 122 if (column == 0) { 123 if (prefix != null) { 124 out.write(prefix); 125 } 126 127 if (!collectingIndent) { 128 for (int i = 0; i < indent; i++) { 129 out.write(' '); 130 } 131 column = indent; 132 } 133 } 134 135 out.write(c); 136 137 if (c == '\n') { 138 bol(); 139 } else { 140 column++; 141 } 142 } 143 } 144 145 /** {@inheritDoc} */ 146 @Override 147 public void write(char[] cbuf, int off, int len) throws IOException { 148 synchronized (lock) { 149 while (len > 0) { 150 write(cbuf[off]); 151 off++; 152 len--; 153 } 154 } 155 } 156 157 /** {@inheritDoc} */ 158 @Override 159 public void write(String str, int off, int len) throws IOException { 160 synchronized (lock) { 161 while (len > 0) { 162 write(str.charAt(off)); 163 off++; 164 len--; 165 } 166 } 167 } 168 169 /** 170 * Indicates that output is at the beginning of a line. 171 */ 172 private void bol() { 173 column = 0; 174 collectingIndent = (maxIndent != 0); 175 indent = 0; 176 } 177} 178