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| 1 | /* | ||
| 2 | * Copyright (c) 1996, 2006, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package java.io; | ||
| 27 | |||
| 28 | |||
| 29 | /** | ||
| 30 | * A buffered character-input stream that keeps track of line numbers. This | ||
| 31 | * class defines methods {@link #setLineNumber(int)} and {@link | ||
| 32 | * #getLineNumber()} for setting and getting the current line number | ||
| 33 | * respectively. | ||
| 34 | * | ||
| 35 | * <p> By default, line numbering begins at 0. This number increments at every | ||
| 36 | * <a href="#lt">line terminator</a> as the data is read, and can be changed | ||
| 37 | * with a call to <tt>setLineNumber(int)</tt>. Note however, that | ||
| 38 | * <tt>setLineNumber(int)</tt> does not actually change the current position in | ||
| 39 | * the stream; it only changes the value that will be returned by | ||
| 40 | * <tt>getLineNumber()</tt>. | ||
| 41 | * | ||
| 42 | * <p> A line is considered to be <a name="lt">terminated</a> by any one of a | ||
| 43 | * line feed ('\n'), a carriage return ('\r'), or a carriage return followed | ||
| 44 | * immediately by a linefeed. | ||
| 45 | * | ||
| 46 | * @author Mark Reinhold | ||
| 47 | * @since JDK1.1 | ||
| 48 | */ | ||
| 49 | |||
| 50 | public class LineNumberReader extends BufferedReader { | ||
| 51 | |||
| 52 | /** The current line number */ | ||
| 53 | private int lineNumber = 0; | ||
| 54 | |||
| 55 | /** The line number of the mark, if any */ | ||
| 56 | private int markedLineNumber; // Defaults to 0 | ||
| 57 | |||
| 58 | /** If the next character is a line feed, skip it */ | ||
| 59 | private boolean skipLF; | ||
| 60 | |||
| 61 | /** The skipLF flag when the mark was set */ | ||
| 62 | private boolean markedSkipLF; | ||
| 63 | |||
| 64 | /** | ||
| 65 | * Create a new line-numbering reader, using the default input-buffer | ||
| 66 | * size. | ||
| 67 | * | ||
| 68 | * @param in | ||
| 69 | * A Reader object to provide the underlying stream | ||
| 70 | */ | ||
| 71 | public LineNumberReader(Reader in) { | ||
| 72 | super(in); | ||
| 73 | } | ||
| 74 | |||
| 75 | /** | ||
| 76 | * Create a new line-numbering reader, reading characters into a buffer of | ||
| 77 | * the given size. | ||
| 78 | * | ||
| 79 | * @param in | ||
| 80 | * A Reader object to provide the underlying stream | ||
| 81 | * | ||
| 82 | * @param sz | ||
| 83 | * An int specifying the size of the buffer | ||
| 84 | */ | ||
| 85 | public LineNumberReader(Reader in, int sz) { | ||
| 86 | super(in, sz); | ||
| 87 | } | ||
| 88 | |||
| 89 | /** | ||
| 90 | * Set the current line number. | ||
| 91 | * | ||
| 92 | * @param lineNumber | ||
| 93 | * An int specifying the line number | ||
| 94 | * | ||
| 95 | * @see #getLineNumber | ||
| 96 | */ | ||
| 97 | public void setLineNumber(int lineNumber) { | ||
| 98 | this.lineNumber = lineNumber; | ||
| 99 | } | ||
| 100 | |||
| 101 | /** | ||
| 102 | * Get the current line number. | ||
| 103 | * | ||
| 104 | * @return The current line number | ||
| 105 | * | ||
| 106 | * @see #setLineNumber | ||
| 107 | */ | ||
| 108 | public int getLineNumber() { | ||
| 109 | return lineNumber; | ||
| 110 | } | ||
| 111 | |||
| 112 | /** | ||
| 113 | * Read a single character. <a href="#lt">Line terminators</a> are | ||
| 114 | * compressed into single newline ('\n') characters. Whenever a line | ||
| 115 | * terminator is read the current line number is incremented. | ||
| 116 | * | ||
| 117 | * @return The character read, or -1 if the end of the stream has been | ||
| 118 | * reached | ||
| 119 | * | ||
| 120 | * @throws IOException | ||
| 121 | * If an I/O error occurs | ||
| 122 | */ | ||
| 123 | public int read() throws IOException { | ||
| 124 | synchronized (lock) { | ||
| 125 | int c = super.read(); | ||
| 126 | if (skipLF) { | ||
| 127 | if (c == '\n') | ||
| 128 | c = super.read(); | ||
| 129 | skipLF = false; | ||
| 130 | } | ||
| 131 | switch (c) { | ||
| 132 | case '\r': | ||
| 133 | skipLF = true; | ||
| 134 | case '\n': /* Fall through */ | ||
| 135 | lineNumber++; | ||
| 136 | return '\n'; | ||
| 137 | } | ||
| 138 | return c; | ||
| 139 | } | ||
| 140 | } | ||
| 141 | |||
| 142 | /** | ||
| 143 | * Read characters into a portion of an array. Whenever a <a | ||
| 144 | * href="#lt">line terminator</a> is read the current line number is | ||
| 145 | * incremented. | ||
| 146 | * | ||
| 147 | * @param cbuf | ||
| 148 | * Destination buffer | ||
| 149 | * | ||
| 150 | * @param off | ||
| 151 | * Offset at which to start storing characters | ||
| 152 | * | ||
| 153 | * @param len | ||
| 154 | * Maximum number of characters to read | ||
| 155 | * | ||
| 156 | * @return The number of bytes read, or -1 if the end of the stream has | ||
| 157 | * already been reached | ||
| 158 | * | ||
| 159 | * @throws IOException | ||
| 160 | * If an I/O error occurs | ||
| 161 | */ | ||
| 162 | public int read(char cbuf[], int off, int len) throws IOException { | ||
| 163 | synchronized (lock) { | ||
| 164 | int n = super.read(cbuf, off, len); | ||
| 165 | |||
| 166 | for (int i = off; i < off + n; i++) { | ||
| 167 | int c = cbuf[i]; | ||
| 168 | if (skipLF) { | ||
| 169 | skipLF = false; | ||
| 170 | if (c == '\n') | ||
| 171 | continue; | ||
| 172 | } | ||
| 173 | switch (c) { | ||
| 174 | case '\r': | ||
| 175 | skipLF = true; | ||
| 176 | case '\n': /* Fall through */ | ||
| 177 | lineNumber++; | ||
| 178 | break; | ||
| 179 | } | ||
| 180 | } | ||
| 181 | |||
| 182 | return n; | ||
| 183 | } | ||
| 184 | } | ||
| 185 | |||
| 186 | /** | ||
| 187 | * Read a line of text. Whenever a <a href="#lt">line terminator</a> is | ||
| 188 | * read the current line number is incremented. | ||
| 189 | * | ||
| 190 | * @return A String containing the contents of the line, not including | ||
| 191 | * any <a href="#lt">line termination characters</a>, or | ||
| 192 | * <tt>null</tt> if the end of the stream has been reached | ||
| 193 | * | ||
| 194 | * @throws IOException | ||
| 195 | * If an I/O error occurs | ||
| 196 | */ | ||
| 197 | public String readLine() throws IOException { | ||
| 198 | synchronized (lock) { | ||
| 199 | String l = super.readLine(skipLF); | ||
| 200 | skipLF = false; | ||
| 201 | if (l != null) | ||
| 202 | lineNumber++; | ||
| 203 | return l; | ||
| 204 | } | ||
| 205 | } | ||
| 206 | |||
| 207 | /** Maximum skip-buffer size */ | ||
| 208 | private static final int maxSkipBufferSize = 8192; | ||
| 209 | |||
| 210 | /** Skip buffer, null until allocated */ | ||
| 211 | private char skipBuffer[] = null; | ||
| 212 | |||
| 213 | /** | ||
| 214 | * Skip characters. | ||
| 215 | * | ||
| 216 | * @param n | ||
| 217 | * The number of characters to skip | ||
| 218 | * | ||
| 219 | * @return The number of characters actually skipped | ||
| 220 | * | ||
| 221 | * @throws IOException | ||
| 222 | * If an I/O error occurs | ||
| 223 | * | ||
| 224 | * @throws IllegalArgumentException | ||
| 225 | * If <tt>n</tt> is negative | ||
| 226 | */ | ||
| 227 | public long skip(long n) throws IOException { | ||
| 228 | if (n < 0) | ||
| 229 | throw new IllegalArgumentException("skip() value is negative"); | ||
| 230 | int nn = (int) Math.min(n, maxSkipBufferSize); | ||
| 231 | synchronized (lock) { | ||
| 232 | if ((skipBuffer == null) || (skipBuffer.length < nn)) | ||
| 233 | skipBuffer = new char[nn]; | ||
| 234 | long r = n; | ||
| 235 | while (r > 0) { | ||
| 236 | int nc = read(skipBuffer, 0, (int) Math.min(r, nn)); | ||
| 237 | if (nc == -1) | ||
| 238 | break; | ||
| 239 | r -= nc; | ||
| 240 | } | ||
| 241 | return n - r; | ||
| 242 | } | ||
| 243 | } | ||
| 244 | |||
| 245 | /** | ||
| 246 | * Mark the present position in the stream. Subsequent calls to reset() | ||
| 247 | * will attempt to reposition the stream to this point, and will also reset | ||
| 248 | * the line number appropriately. | ||
| 249 | * | ||
| 250 | * @param readAheadLimit | ||
| 251 | * Limit on the number of characters that may be read while still | ||
| 252 | * preserving the mark. After reading this many characters, | ||
| 253 | * attempting to reset the stream may fail. | ||
| 254 | * | ||
| 255 | * @throws IOException | ||
| 256 | * If an I/O error occurs | ||
| 257 | */ | ||
| 258 | public void mark(int readAheadLimit) throws IOException { | ||
| 259 | synchronized (lock) { | ||
| 260 | super.mark(readAheadLimit); | ||
| 261 | markedLineNumber = lineNumber; | ||
| 262 | markedSkipLF = skipLF; | ||
| 263 | } | ||
| 264 | } | ||
| 265 | |||
| 266 | /** | ||
| 267 | * Reset the stream to the most recent mark. | ||
| 268 | * | ||
| 269 | * @throws IOException | ||
| 270 | * If the stream has not been marked, or if the mark has been | ||
| 271 | * invalidated | ||
| 272 | */ | ||
| 273 | public void reset() throws IOException { | ||
| 274 | synchronized (lock) { | ||
| 275 | super.reset(); | ||
| 276 | lineNumber = markedLineNumber; | ||
| 277 | skipLF = markedSkipLF; | ||
| 278 | } | ||
| 279 | } | ||
| 280 | |||
| 281 | } | ||