1 /* 2 * Copyright (c) 1994, 2004, 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 * A data output stream lets an application write primitive Java data 30 * types to an output stream in a portable way. An application can 31 * then use a data input stream to read the data back in. 32 * 33 * @author unascribed 34 * @see java.io.DataInputStream 35 * @since JDK1.0 36 */ 37 public 38 class DataOutputStream extends FilterOutputStream implements DataOutput { 39 /** 40 * The number of bytes written to the data output stream so far. 41 * If this counter overflows, it will be wrapped to Integer.MAX_VALUE. 42 */ 43 protected int written; 44 45 /** 46 * bytearr is initialized on demand by writeUTF 47 */ 48 private byte[] bytearr = null; 49 50 /** 51 * Creates a new data output stream to write data to the specified 52 * underlying output stream. The counter <code>written</code> is 53 * set to zero. 54 * 55 * @param out the underlying output stream, to be saved for later 56 * use. 57 * @see java.io.FilterOutputStream#out 58 */ DataOutputStream(OutputStream out)59 public DataOutputStream(OutputStream out) { 60 super(out); 61 } 62 63 /** 64 * Increases the written counter by the specified value 65 * until it reaches Integer.MAX_VALUE. 66 */ incCount(int value)67 private void incCount(int value) { 68 int temp = written + value; 69 if (temp < 0) { 70 temp = Integer.MAX_VALUE; 71 } 72 written = temp; 73 } 74 75 /** 76 * Writes the specified byte (the low eight bits of the argument 77 * <code>b</code>) to the underlying output stream. If no exception 78 * is thrown, the counter <code>written</code> is incremented by 79 * <code>1</code>. 80 * <p> 81 * Implements the <code>write</code> method of <code>OutputStream</code>. 82 * 83 * @param b the <code>byte</code> to be written. 84 * @exception IOException if an I/O error occurs. 85 * @see java.io.FilterOutputStream#out 86 */ write(int b)87 public synchronized void write(int b) throws IOException { 88 out.write(b); 89 incCount(1); 90 } 91 92 /** 93 * Writes <code>len</code> bytes from the specified byte array 94 * starting at offset <code>off</code> to the underlying output stream. 95 * If no exception is thrown, the counter <code>written</code> is 96 * incremented by <code>len</code>. 97 * 98 * @param b the data. 99 * @param off the start offset in the data. 100 * @param len the number of bytes to write. 101 * @exception IOException if an I/O error occurs. 102 * @see java.io.FilterOutputStream#out 103 */ write(byte b[], int off, int len)104 public synchronized void write(byte b[], int off, int len) 105 throws IOException 106 { 107 out.write(b, off, len); 108 incCount(len); 109 } 110 111 /** 112 * Flushes this data output stream. This forces any buffered output 113 * bytes to be written out to the stream. 114 * <p> 115 * The <code>flush</code> method of <code>DataOutputStream</code> 116 * calls the <code>flush</code> method of its underlying output stream. 117 * 118 * @exception IOException if an I/O error occurs. 119 * @see java.io.FilterOutputStream#out 120 * @see java.io.OutputStream#flush() 121 */ flush()122 public void flush() throws IOException { 123 out.flush(); 124 } 125 126 /** 127 * Writes a <code>boolean</code> to the underlying output stream as 128 * a 1-byte value. The value <code>true</code> is written out as the 129 * value <code>(byte)1</code>; the value <code>false</code> is 130 * written out as the value <code>(byte)0</code>. If no exception is 131 * thrown, the counter <code>written</code> is incremented by 132 * <code>1</code>. 133 * 134 * @param v a <code>boolean</code> value to be written. 135 * @exception IOException if an I/O error occurs. 136 * @see java.io.FilterOutputStream#out 137 */ writeBoolean(boolean v)138 public final void writeBoolean(boolean v) throws IOException { 139 out.write(v ? 1 : 0); 140 incCount(1); 141 } 142 143 /** 144 * Writes out a <code>byte</code> to the underlying output stream as 145 * a 1-byte value. If no exception is thrown, the counter 146 * <code>written</code> is incremented by <code>1</code>. 147 * 148 * @param v a <code>byte</code> value to be written. 149 * @exception IOException if an I/O error occurs. 150 * @see java.io.FilterOutputStream#out 151 */ writeByte(int v)152 public final void writeByte(int v) throws IOException { 153 out.write(v); 154 incCount(1); 155 } 156 157 /** 158 * Writes a <code>short</code> to the underlying output stream as two 159 * bytes, high byte first. If no exception is thrown, the counter 160 * <code>written</code> is incremented by <code>2</code>. 161 * 162 * @param v a <code>short</code> to be written. 163 * @exception IOException if an I/O error occurs. 164 * @see java.io.FilterOutputStream#out 165 */ writeShort(int v)166 public final void writeShort(int v) throws IOException { 167 out.write((v >>> 8) & 0xFF); 168 out.write((v >>> 0) & 0xFF); 169 incCount(2); 170 } 171 172 /** 173 * Writes a <code>char</code> to the underlying output stream as a 174 * 2-byte value, high byte first. If no exception is thrown, the 175 * counter <code>written</code> is incremented by <code>2</code>. 176 * 177 * @param v a <code>char</code> value to be written. 178 * @exception IOException if an I/O error occurs. 179 * @see java.io.FilterOutputStream#out 180 */ writeChar(int v)181 public final void writeChar(int v) throws IOException { 182 out.write((v >>> 8) & 0xFF); 183 out.write((v >>> 0) & 0xFF); 184 incCount(2); 185 } 186 187 /** 188 * Writes an <code>int</code> to the underlying output stream as four 189 * bytes, high byte first. If no exception is thrown, the counter 190 * <code>written</code> is incremented by <code>4</code>. 191 * 192 * @param v an <code>int</code> to be written. 193 * @exception IOException if an I/O error occurs. 194 * @see java.io.FilterOutputStream#out 195 */ writeInt(int v)196 public final void writeInt(int v) throws IOException { 197 out.write((v >>> 24) & 0xFF); 198 out.write((v >>> 16) & 0xFF); 199 out.write((v >>> 8) & 0xFF); 200 out.write((v >>> 0) & 0xFF); 201 incCount(4); 202 } 203 204 private byte writeBuffer[] = new byte[8]; 205 206 /** 207 * Writes a <code>long</code> to the underlying output stream as eight 208 * bytes, high byte first. In no exception is thrown, the counter 209 * <code>written</code> is incremented by <code>8</code>. 210 * 211 * @param v a <code>long</code> to be written. 212 * @exception IOException if an I/O error occurs. 213 * @see java.io.FilterOutputStream#out 214 */ writeLong(long v)215 public final void writeLong(long v) throws IOException { 216 writeBuffer[0] = (byte)(v >>> 56); 217 writeBuffer[1] = (byte)(v >>> 48); 218 writeBuffer[2] = (byte)(v >>> 40); 219 writeBuffer[3] = (byte)(v >>> 32); 220 writeBuffer[4] = (byte)(v >>> 24); 221 writeBuffer[5] = (byte)(v >>> 16); 222 writeBuffer[6] = (byte)(v >>> 8); 223 writeBuffer[7] = (byte)(v >>> 0); 224 out.write(writeBuffer, 0, 8); 225 incCount(8); 226 } 227 228 /** 229 * Converts the float argument to an <code>int</code> using the 230 * <code>floatToIntBits</code> method in class <code>Float</code>, 231 * and then writes that <code>int</code> value to the underlying 232 * output stream as a 4-byte quantity, high byte first. If no 233 * exception is thrown, the counter <code>written</code> is 234 * incremented by <code>4</code>. 235 * 236 * @param v a <code>float</code> value to be written. 237 * @exception IOException if an I/O error occurs. 238 * @see java.io.FilterOutputStream#out 239 * @see java.lang.Float#floatToIntBits(float) 240 */ writeFloat(float v)241 public final void writeFloat(float v) throws IOException { 242 writeInt(Float.floatToIntBits(v)); 243 } 244 245 /** 246 * Converts the double argument to a <code>long</code> using the 247 * <code>doubleToLongBits</code> method in class <code>Double</code>, 248 * and then writes that <code>long</code> value to the underlying 249 * output stream as an 8-byte quantity, high byte first. If no 250 * exception is thrown, the counter <code>written</code> is 251 * incremented by <code>8</code>. 252 * 253 * @param v a <code>double</code> value to be written. 254 * @exception IOException if an I/O error occurs. 255 * @see java.io.FilterOutputStream#out 256 * @see java.lang.Double#doubleToLongBits(double) 257 */ writeDouble(double v)258 public final void writeDouble(double v) throws IOException { 259 writeLong(Double.doubleToLongBits(v)); 260 } 261 262 /** 263 * Writes out the string to the underlying output stream as a 264 * sequence of bytes. Each character in the string is written out, in 265 * sequence, by discarding its high eight bits. If no exception is 266 * thrown, the counter <code>written</code> is incremented by the 267 * length of <code>s</code>. 268 * 269 * @param s a string of bytes to be written. 270 * @exception IOException if an I/O error occurs. 271 * @see java.io.FilterOutputStream#out 272 */ writeBytes(String s)273 public final void writeBytes(String s) throws IOException { 274 int len = s.length(); 275 for (int i = 0 ; i < len ; i++) { 276 out.write((byte)s.charAt(i)); 277 } 278 incCount(len); 279 } 280 281 /** 282 * Writes a string to the underlying output stream as a sequence of 283 * characters. Each character is written to the data output stream as 284 * if by the <code>writeChar</code> method. If no exception is 285 * thrown, the counter <code>written</code> is incremented by twice 286 * the length of <code>s</code>. 287 * 288 * @param s a <code>String</code> value to be written. 289 * @exception IOException if an I/O error occurs. 290 * @see java.io.DataOutputStream#writeChar(int) 291 * @see java.io.FilterOutputStream#out 292 */ writeChars(String s)293 public final void writeChars(String s) throws IOException { 294 int len = s.length(); 295 for (int i = 0 ; i < len ; i++) { 296 int v = s.charAt(i); 297 out.write((v >>> 8) & 0xFF); 298 out.write((v >>> 0) & 0xFF); 299 } 300 incCount(len * 2); 301 } 302 303 /** 304 * Writes a string to the underlying output stream using 305 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a> 306 * encoding in a machine-independent manner. 307 * <p> 308 * First, two bytes are written to the output stream as if by the 309 * <code>writeShort</code> method giving the number of bytes to 310 * follow. This value is the number of bytes actually written out, 311 * not the length of the string. Following the length, each character 312 * of the string is output, in sequence, using the modified UTF-8 encoding 313 * for the character. If no exception is thrown, the counter 314 * <code>written</code> is incremented by the total number of 315 * bytes written to the output stream. This will be at least two 316 * plus the length of <code>str</code>, and at most two plus 317 * thrice the length of <code>str</code>. 318 * 319 * @param str a string to be written. 320 * @exception IOException if an I/O error occurs. 321 */ writeUTF(String str)322 public final void writeUTF(String str) throws IOException { 323 writeUTF(str, this); 324 } 325 326 /** 327 * Writes a string to the specified DataOutput using 328 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a> 329 * encoding in a machine-independent manner. 330 * <p> 331 * First, two bytes are written to out as if by the <code>writeShort</code> 332 * method giving the number of bytes to follow. This value is the number of 333 * bytes actually written out, not the length of the string. Following the 334 * length, each character of the string is output, in sequence, using the 335 * modified UTF-8 encoding for the character. If no exception is thrown, the 336 * counter <code>written</code> is incremented by the total number of 337 * bytes written to the output stream. This will be at least two 338 * plus the length of <code>str</code>, and at most two plus 339 * thrice the length of <code>str</code>. 340 * 341 * @param str a string to be written. 342 * @param out destination to write to 343 * @return The number of bytes written out. 344 * @exception IOException if an I/O error occurs. 345 */ writeUTF(String str, DataOutput out)346 static int writeUTF(String str, DataOutput out) throws IOException { 347 int strlen = str.length(); 348 int utflen = 0; 349 int c, count = 0; 350 351 /* use charAt instead of copying String to char array */ 352 for (int i = 0; i < strlen; i++) { 353 c = str.charAt(i); 354 if ((c >= 0x0001) && (c <= 0x007F)) { 355 utflen++; 356 } else if (c > 0x07FF) { 357 utflen += 3; 358 } else { 359 utflen += 2; 360 } 361 } 362 363 if (utflen > 65535) 364 throw new UTFDataFormatException( 365 "encoded string too long: " + utflen + " bytes"); 366 367 byte[] bytearr = null; 368 if (out instanceof DataOutputStream) { 369 DataOutputStream dos = (DataOutputStream)out; 370 if(dos.bytearr == null || (dos.bytearr.length < (utflen+2))) 371 dos.bytearr = new byte[(utflen*2) + 2]; 372 bytearr = dos.bytearr; 373 } else { 374 bytearr = new byte[utflen+2]; 375 } 376 377 bytearr[count++] = (byte) ((utflen >>> 8) & 0xFF); 378 bytearr[count++] = (byte) ((utflen >>> 0) & 0xFF); 379 380 int i=0; 381 for (i=0; i<strlen; i++) { 382 c = str.charAt(i); 383 if (!((c >= 0x0001) && (c <= 0x007F))) break; 384 bytearr[count++] = (byte) c; 385 } 386 387 for (;i < strlen; i++){ 388 c = str.charAt(i); 389 if ((c >= 0x0001) && (c <= 0x007F)) { 390 bytearr[count++] = (byte) c; 391 392 } else if (c > 0x07FF) { 393 bytearr[count++] = (byte) (0xE0 | ((c >> 12) & 0x0F)); 394 bytearr[count++] = (byte) (0x80 | ((c >> 6) & 0x3F)); 395 bytearr[count++] = (byte) (0x80 | ((c >> 0) & 0x3F)); 396 } else { 397 bytearr[count++] = (byte) (0xC0 | ((c >> 6) & 0x1F)); 398 bytearr[count++] = (byte) (0x80 | ((c >> 0) & 0x3F)); 399 } 400 } 401 out.write(bytearr, 0, utflen+2); 402 return utflen + 2; 403 } 404 405 /** 406 * Returns the current value of the counter <code>written</code>, 407 * the number of bytes written to this data output stream so far. 408 * If the counter overflows, it will be wrapped to Integer.MAX_VALUE. 409 * 410 * @return the value of the <code>written</code> field. 411 * @see java.io.DataOutputStream#written 412 */ size()413 public final int size() { 414 return written; 415 } 416 } 417