38 * @author Arthur van Hoff
39 * @see java.io.DataOutputStream
40 * @since 1.0
41 */
42 public
43 class DataInputStream extends FilterInputStream implements DataInput {
44
45 /**
46 * Creates a DataInputStream that uses the specified
47 * underlying InputStream.
48 *
49 * @param in the specified input stream
50 */
51 public DataInputStream(InputStream in) {
52 super(in);
53 }
54
55 /**
56 * working arrays initialized on demand by readUTF
57 */
58 private byte bytearr[] = new byte[80];
59 private char chararr[] = new char[80];
60
61 /**
62 * Reads some number of bytes from the contained input stream and
63 * stores them into the buffer array <code>b</code>. The number of
64 * bytes actually read is returned as an integer. This method blocks
65 * until input data is available, end of file is detected, or an
66 * exception is thrown.
67 *
68 * <p>If <code>b</code> is null, a <code>NullPointerException</code> is
69 * thrown. If the length of <code>b</code> is zero, then no bytes are
70 * read and <code>0</code> is returned; otherwise, there is an attempt
71 * to read at least one byte. If no byte is available because the
72 * stream is at end of file, the value <code>-1</code> is returned;
73 * otherwise, at least one byte is read and stored into <code>b</code>.
74 *
75 * <p>The first byte read is stored into element <code>b[0]</code>, the
76 * next one into <code>b[1]</code>, and so on. The number of bytes read
77 * is, at most, equal to the length of <code>b</code>. Let <code>k</code>
78 * be the number of bytes actually read; these bytes will be stored in
79 * elements <code>b[0]</code> through <code>b[k-1]</code>, leaving
80 * elements <code>b[k]</code> through <code>b[b.length-1]</code>
81 * unaffected.
82 *
83 * <p>The <code>read(b)</code> method has the same effect as:
84 * <blockquote><pre>
85 * read(b, 0, b.length)
86 * </pre></blockquote>
87 *
88 * @param b the buffer into which the data is read.
89 * @return the total number of bytes read into the buffer, or
90 * <code>-1</code> if there is no more data because the end
91 * of the stream has been reached.
92 * @exception IOException if the first byte cannot be read for any reason
93 * other than end of file, the stream has been closed and the underlying
94 * input stream does not support reading after close, or another I/O
95 * error occurs.
96 * @see java.io.FilterInputStream#in
97 * @see java.io.InputStream#read(byte[], int, int)
98 */
99 public final int read(byte b[]) throws IOException {
100 return in.read(b, 0, b.length);
101 }
102
103 /**
104 * Reads up to <code>len</code> bytes of data from the contained
105 * input stream into an array of bytes. An attempt is made to read
106 * as many as <code>len</code> bytes, but a smaller number may be read,
107 * possibly zero. The number of bytes actually read is returned as an
108 * integer.
109 *
110 * <p> This method blocks until input data is available, end of file is
111 * detected, or an exception is thrown.
112 *
113 * <p> If <code>len</code> is zero, then no bytes are read and
114 * <code>0</code> is returned; otherwise, there is an attempt to read at
115 * least one byte. If no byte is available because the stream is at end of
116 * file, the value <code>-1</code> is returned; otherwise, at least one
117 * byte is read and stored into <code>b</code>.
118 *
119 * <p> The first byte read is stored into element <code>b[off]</code>, the
128 * <code>b[off]</code> and elements <code>b[off+len]</code> through
129 * <code>b[b.length-1]</code> are unaffected.
130 *
131 * @param b the buffer into which the data is read.
132 * @param off the start offset in the destination array <code>b</code>
133 * @param len the maximum number of bytes read.
134 * @return the total number of bytes read into the buffer, or
135 * <code>-1</code> if there is no more data because the end
136 * of the stream has been reached.
137 * @exception NullPointerException If <code>b</code> is <code>null</code>.
138 * @exception IndexOutOfBoundsException If <code>off</code> is negative,
139 * <code>len</code> is negative, or <code>len</code> is greater than
140 * <code>b.length - off</code>
141 * @exception IOException if the first byte cannot be read for any reason
142 * other than end of file, the stream has been closed and the underlying
143 * input stream does not support reading after close, or another I/O
144 * error occurs.
145 * @see java.io.FilterInputStream#in
146 * @see java.io.InputStream#read(byte[], int, int)
147 */
148 public final int read(byte b[], int off, int len) throws IOException {
149 return in.read(b, off, len);
150 }
151
152 /**
153 * See the general contract of the {@code readFully}
154 * method of {@code DataInput}.
155 * <p>
156 * Bytes
157 * for this operation are read from the contained
158 * input stream.
159 *
160 * @param b the buffer into which the data is read.
161 * @throws NullPointerException if {@code b} is {@code null}.
162 * @throws EOFException if this input stream reaches the end before
163 * reading all the bytes.
164 * @throws IOException the stream has been closed and the contained
165 * input stream does not support reading after close, or
166 * another I/O error occurs.
167 * @see java.io.FilterInputStream#in
168 */
169 public final void readFully(byte b[]) throws IOException {
170 readFully(b, 0, b.length);
171 }
172
173 /**
174 * See the general contract of the {@code readFully}
175 * method of {@code DataInput}.
176 * <p>
177 * Bytes
178 * for this operation are read from the contained
179 * input stream.
180 *
181 * @param b the buffer into which the data is read.
182 * @param off the start offset in the data array {@code b}.
183 * @param len the number of bytes to read.
184 * @exception NullPointerException if {@code b} is {@code null}.
185 * @exception IndexOutOfBoundsException if {@code off} is negative,
186 * {@code len} is negative, or {@code len} is greater than
187 * {@code b.length - off}.
188 * @exception EOFException if this input stream reaches the end before
189 * reading all the bytes.
190 * @exception IOException the stream has been closed and the contained
191 * input stream does not support reading after close, or
192 * another I/O error occurs.
193 * @see java.io.FilterInputStream#in
194 */
195 public final void readFully(byte b[], int off, int len) throws IOException {
196 if (len < 0)
197 throw new IndexOutOfBoundsException();
198 int n = 0;
199 while (n < len) {
200 int count = in.read(b, off + n, len - n);
201 if (count < 0)
202 throw new EOFException();
203 n += count;
204 }
205 }
206
207 /**
208 * See the general contract of the <code>skipBytes</code>
209 * method of <code>DataInput</code>.
210 * <p>
211 * Bytes for this operation are read from the contained
212 * input stream.
213 *
214 * @param n the number of bytes to be skipped.
215 * @return the actual number of bytes skipped.
381 *
382 * @return the next four bytes of this input stream, interpreted as an
383 * <code>int</code>.
384 * @exception EOFException if this input stream reaches the end before
385 * reading four bytes.
386 * @exception IOException the stream has been closed and the contained
387 * input stream does not support reading after close, or
388 * another I/O error occurs.
389 * @see java.io.FilterInputStream#in
390 */
391 public final int readInt() throws IOException {
392 int ch1 = in.read();
393 int ch2 = in.read();
394 int ch3 = in.read();
395 int ch4 = in.read();
396 if ((ch1 | ch2 | ch3 | ch4) < 0)
397 throw new EOFException();
398 return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
399 }
400
401 private byte readBuffer[] = new byte[8];
402
403 /**
404 * See the general contract of the <code>readLong</code>
405 * method of <code>DataInput</code>.
406 * <p>
407 * Bytes
408 * for this operation are read from the contained
409 * input stream.
410 *
411 * @return the next eight bytes of this input stream, interpreted as a
412 * <code>long</code>.
413 * @exception EOFException if this input stream reaches the end before
414 * reading eight bytes.
415 * @exception IOException the stream has been closed and the contained
416 * input stream does not support reading after close, or
417 * another I/O error occurs.
418 * @see java.io.FilterInputStream#in
419 */
420 public final long readLong() throws IOException {
421 readFully(readBuffer, 0, 8);
456 * method of <code>DataInput</code>.
457 * <p>
458 * Bytes
459 * for this operation are read from the contained
460 * input stream.
461 *
462 * @return the next eight bytes of this input stream, interpreted as a
463 * <code>double</code>.
464 * @exception EOFException if this input stream reaches the end before
465 * reading eight bytes.
466 * @exception IOException the stream has been closed and the contained
467 * input stream does not support reading after close, or
468 * another I/O error occurs.
469 * @see java.io.DataInputStream#readLong()
470 * @see java.lang.Double#longBitsToDouble(long)
471 */
472 public final double readDouble() throws IOException {
473 return Double.longBitsToDouble(readLong());
474 }
475
476 private char lineBuffer[];
477
478 /**
479 * See the general contract of the <code>readLine</code>
480 * method of <code>DataInput</code>.
481 * <p>
482 * Bytes
483 * for this operation are read from the contained
484 * input stream.
485 *
486 * @deprecated This method does not properly convert bytes to characters.
487 * As of JDK 1.1, the preferred way to read lines of text is via the
488 * <code>BufferedReader.readLine()</code> method. Programs that use the
489 * <code>DataInputStream</code> class to read lines can be converted to use
490 * the <code>BufferedReader</code> class by replacing code of the form:
491 * <blockquote><pre>
492 * DataInputStream d = new DataInputStream(in);
493 * </pre></blockquote>
494 * with:
495 * <blockquote><pre>
496 * BufferedReader d
497 * = new BufferedReader(new InputStreamReader(in));
498 * </pre></blockquote>
499 *
500 * @return the next line of text from this input stream.
501 * @exception IOException if an I/O error occurs.
502 * @see java.io.BufferedReader#readLine()
503 * @see java.io.FilterInputStream#in
504 */
505 @Deprecated
506 public final String readLine() throws IOException {
507 char buf[] = lineBuffer;
508
509 if (buf == null) {
510 buf = lineBuffer = new char[128];
511 }
512
513 int room = buf.length;
514 int offset = 0;
515 int c;
516
517 loop: while (true) {
518 switch (c = in.read()) {
519 case -1:
520 case '\n':
521 break loop;
522
523 case '\r':
524 int c2 = in.read();
525 if ((c2 != '\n') && (c2 != -1)) {
526 if (!(in instanceof PushbackInputStream)) {
527 this.in = new PushbackInputStream(in);
|
38 * @author Arthur van Hoff
39 * @see java.io.DataOutputStream
40 * @since 1.0
41 */
42 public
43 class DataInputStream extends FilterInputStream implements DataInput {
44
45 /**
46 * Creates a DataInputStream that uses the specified
47 * underlying InputStream.
48 *
49 * @param in the specified input stream
50 */
51 public DataInputStream(InputStream in) {
52 super(in);
53 }
54
55 /**
56 * working arrays initialized on demand by readUTF
57 */
58 private byte[] bytearr = new byte[80];
59 private char[] chararr = new char[80];
60
61 /**
62 * Reads some number of bytes from the contained input stream and
63 * stores them into the buffer array <code>b</code>. The number of
64 * bytes actually read is returned as an integer. This method blocks
65 * until input data is available, end of file is detected, or an
66 * exception is thrown.
67 *
68 * <p>If <code>b</code> is null, a <code>NullPointerException</code> is
69 * thrown. If the length of <code>b</code> is zero, then no bytes are
70 * read and <code>0</code> is returned; otherwise, there is an attempt
71 * to read at least one byte. If no byte is available because the
72 * stream is at end of file, the value <code>-1</code> is returned;
73 * otherwise, at least one byte is read and stored into <code>b</code>.
74 *
75 * <p>The first byte read is stored into element <code>b[0]</code>, the
76 * next one into <code>b[1]</code>, and so on. The number of bytes read
77 * is, at most, equal to the length of <code>b</code>. Let <code>k</code>
78 * be the number of bytes actually read; these bytes will be stored in
79 * elements <code>b[0]</code> through <code>b[k-1]</code>, leaving
80 * elements <code>b[k]</code> through <code>b[b.length-1]</code>
81 * unaffected.
82 *
83 * <p>The <code>read(b)</code> method has the same effect as:
84 * <blockquote><pre>
85 * read(b, 0, b.length)
86 * </pre></blockquote>
87 *
88 * @param b the buffer into which the data is read.
89 * @return the total number of bytes read into the buffer, or
90 * <code>-1</code> if there is no more data because the end
91 * of the stream has been reached.
92 * @exception IOException if the first byte cannot be read for any reason
93 * other than end of file, the stream has been closed and the underlying
94 * input stream does not support reading after close, or another I/O
95 * error occurs.
96 * @see java.io.FilterInputStream#in
97 * @see java.io.InputStream#read(byte[], int, int)
98 */
99 public final int read(byte[] b) throws IOException {
100 return in.read(b, 0, b.length);
101 }
102
103 /**
104 * Reads up to <code>len</code> bytes of data from the contained
105 * input stream into an array of bytes. An attempt is made to read
106 * as many as <code>len</code> bytes, but a smaller number may be read,
107 * possibly zero. The number of bytes actually read is returned as an
108 * integer.
109 *
110 * <p> This method blocks until input data is available, end of file is
111 * detected, or an exception is thrown.
112 *
113 * <p> If <code>len</code> is zero, then no bytes are read and
114 * <code>0</code> is returned; otherwise, there is an attempt to read at
115 * least one byte. If no byte is available because the stream is at end of
116 * file, the value <code>-1</code> is returned; otherwise, at least one
117 * byte is read and stored into <code>b</code>.
118 *
119 * <p> The first byte read is stored into element <code>b[off]</code>, the
128 * <code>b[off]</code> and elements <code>b[off+len]</code> through
129 * <code>b[b.length-1]</code> are unaffected.
130 *
131 * @param b the buffer into which the data is read.
132 * @param off the start offset in the destination array <code>b</code>
133 * @param len the maximum number of bytes read.
134 * @return the total number of bytes read into the buffer, or
135 * <code>-1</code> if there is no more data because the end
136 * of the stream has been reached.
137 * @exception NullPointerException If <code>b</code> is <code>null</code>.
138 * @exception IndexOutOfBoundsException If <code>off</code> is negative,
139 * <code>len</code> is negative, or <code>len</code> is greater than
140 * <code>b.length - off</code>
141 * @exception IOException if the first byte cannot be read for any reason
142 * other than end of file, the stream has been closed and the underlying
143 * input stream does not support reading after close, or another I/O
144 * error occurs.
145 * @see java.io.FilterInputStream#in
146 * @see java.io.InputStream#read(byte[], int, int)
147 */
148 public final int read(byte[] b, int off, int len) throws IOException {
149 return in.read(b, off, len);
150 }
151
152 /**
153 * See the general contract of the {@code readFully}
154 * method of {@code DataInput}.
155 * <p>
156 * Bytes
157 * for this operation are read from the contained
158 * input stream.
159 *
160 * @param b the buffer into which the data is read.
161 * @throws NullPointerException if {@code b} is {@code null}.
162 * @throws EOFException if this input stream reaches the end before
163 * reading all the bytes.
164 * @throws IOException the stream has been closed and the contained
165 * input stream does not support reading after close, or
166 * another I/O error occurs.
167 * @see java.io.FilterInputStream#in
168 */
169 public final void readFully(byte[] b) throws IOException {
170 readFully(b, 0, b.length);
171 }
172
173 /**
174 * See the general contract of the {@code readFully}
175 * method of {@code DataInput}.
176 * <p>
177 * Bytes
178 * for this operation are read from the contained
179 * input stream.
180 *
181 * @param b the buffer into which the data is read.
182 * @param off the start offset in the data array {@code b}.
183 * @param len the number of bytes to read.
184 * @exception NullPointerException if {@code b} is {@code null}.
185 * @exception IndexOutOfBoundsException if {@code off} is negative,
186 * {@code len} is negative, or {@code len} is greater than
187 * {@code b.length - off}.
188 * @exception EOFException if this input stream reaches the end before
189 * reading all the bytes.
190 * @exception IOException the stream has been closed and the contained
191 * input stream does not support reading after close, or
192 * another I/O error occurs.
193 * @see java.io.FilterInputStream#in
194 */
195 public final void readFully(byte[] b, int off, int len) throws IOException {
196 if (len < 0)
197 throw new IndexOutOfBoundsException();
198 int n = 0;
199 while (n < len) {
200 int count = in.read(b, off + n, len - n);
201 if (count < 0)
202 throw new EOFException();
203 n += count;
204 }
205 }
206
207 /**
208 * See the general contract of the <code>skipBytes</code>
209 * method of <code>DataInput</code>.
210 * <p>
211 * Bytes for this operation are read from the contained
212 * input stream.
213 *
214 * @param n the number of bytes to be skipped.
215 * @return the actual number of bytes skipped.
381 *
382 * @return the next four bytes of this input stream, interpreted as an
383 * <code>int</code>.
384 * @exception EOFException if this input stream reaches the end before
385 * reading four bytes.
386 * @exception IOException the stream has been closed and the contained
387 * input stream does not support reading after close, or
388 * another I/O error occurs.
389 * @see java.io.FilterInputStream#in
390 */
391 public final int readInt() throws IOException {
392 int ch1 = in.read();
393 int ch2 = in.read();
394 int ch3 = in.read();
395 int ch4 = in.read();
396 if ((ch1 | ch2 | ch3 | ch4) < 0)
397 throw new EOFException();
398 return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
399 }
400
401 private byte[] readBuffer = new byte[8];
402
403 /**
404 * See the general contract of the <code>readLong</code>
405 * method of <code>DataInput</code>.
406 * <p>
407 * Bytes
408 * for this operation are read from the contained
409 * input stream.
410 *
411 * @return the next eight bytes of this input stream, interpreted as a
412 * <code>long</code>.
413 * @exception EOFException if this input stream reaches the end before
414 * reading eight bytes.
415 * @exception IOException the stream has been closed and the contained
416 * input stream does not support reading after close, or
417 * another I/O error occurs.
418 * @see java.io.FilterInputStream#in
419 */
420 public final long readLong() throws IOException {
421 readFully(readBuffer, 0, 8);
456 * method of <code>DataInput</code>.
457 * <p>
458 * Bytes
459 * for this operation are read from the contained
460 * input stream.
461 *
462 * @return the next eight bytes of this input stream, interpreted as a
463 * <code>double</code>.
464 * @exception EOFException if this input stream reaches the end before
465 * reading eight bytes.
466 * @exception IOException the stream has been closed and the contained
467 * input stream does not support reading after close, or
468 * another I/O error occurs.
469 * @see java.io.DataInputStream#readLong()
470 * @see java.lang.Double#longBitsToDouble(long)
471 */
472 public final double readDouble() throws IOException {
473 return Double.longBitsToDouble(readLong());
474 }
475
476 private char[] lineBuffer;
477
478 /**
479 * See the general contract of the <code>readLine</code>
480 * method of <code>DataInput</code>.
481 * <p>
482 * Bytes
483 * for this operation are read from the contained
484 * input stream.
485 *
486 * @deprecated This method does not properly convert bytes to characters.
487 * As of JDK 1.1, the preferred way to read lines of text is via the
488 * <code>BufferedReader.readLine()</code> method. Programs that use the
489 * <code>DataInputStream</code> class to read lines can be converted to use
490 * the <code>BufferedReader</code> class by replacing code of the form:
491 * <blockquote><pre>
492 * DataInputStream d = new DataInputStream(in);
493 * </pre></blockquote>
494 * with:
495 * <blockquote><pre>
496 * BufferedReader d
497 * = new BufferedReader(new InputStreamReader(in));
498 * </pre></blockquote>
499 *
500 * @return the next line of text from this input stream.
501 * @exception IOException if an I/O error occurs.
502 * @see java.io.BufferedReader#readLine()
503 * @see java.io.FilterInputStream#in
504 */
505 @Deprecated
506 public final String readLine() throws IOException {
507 char[] buf = lineBuffer;
508
509 if (buf == null) {
510 buf = lineBuffer = new char[128];
511 }
512
513 int room = buf.length;
514 int offset = 0;
515 int c;
516
517 loop: while (true) {
518 switch (c = in.read()) {
519 case -1:
520 case '\n':
521 break loop;
522
523 case '\r':
524 int c2 = in.read();
525 if ((c2 != '\n') && (c2 != -1)) {
526 if (!(in instanceof PushbackInputStream)) {
527 this.in = new PushbackInputStream(in);
|