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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 | +} | |