--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.base/share/classes/java/io/DataInput.java Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,589 @@
+/*
+ * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.io;
+
+/**
+ * The {@code DataInput} interface provides
+ * for reading bytes from a binary stream and
+ * reconstructing from them data in any of
+ * the Java primitive types. There is also
+ * a
+ * facility for reconstructing a {@code String}
+ * from data in
+ * <a href="#modified-utf-8">modified UTF-8</a>
+ * format.
+ * <p>
+ * It is generally true of all the reading
+ * routines in this interface that if end of
+ * file is reached before the desired number
+ * of bytes has been read, an {@code EOFException}
+ * (which is a kind of {@code IOException})
+ * is thrown. If any byte cannot be read for
+ * any reason other than end of file, an {@code IOException}
+ * other than {@code EOFException} is
+ * thrown. In particular, an {@code IOException}
+ * may be thrown if the input stream has been
+ * closed.
+ *
+ * <h3><a name="modified-utf-8">Modified UTF-8</a></h3>
+ * <p>
+ * Implementations of the DataInput and DataOutput interfaces represent
+ * Unicode strings in a format that is a slight modification of UTF-8.
+ * (For information regarding the standard UTF-8 format, see section
+ * <i>3.9 Unicode Encoding Forms</i> of <i>The Unicode Standard, Version
+ * 4.0</i>).
+ * Note that in the following table, the most significant bit appears in the
+ * far left-hand column.
+ *
+ * <blockquote>
+ * <table border="1" cellspacing="0" cellpadding="8"
+ * summary="Bit values and bytes">
+ * <tr>
+ * <th colspan="9"><span style="font-weight:normal">
+ * All characters in the range {@code '\u005Cu0001'} to
+ * {@code '\u005Cu007F'} are represented by a single byte:</span></th>
+ * </tr>
+ * <tr>
+ * <td></td>
+ * <th colspan="8" id="bit_a">Bit Values</th>
+ * </tr>
+ * <tr>
+ * <th id="byte1_a">Byte 1</th>
+ * <td><center>0</center>
+ * <td colspan="7"><center>bits 6-0</center>
+ * </tr>
+ * <tr>
+ * <th colspan="9"><span style="font-weight:normal">
+ * The null character {@code '\u005Cu0000'} and characters
+ * in the range {@code '\u005Cu0080'} to {@code '\u005Cu07FF'} are
+ * represented by a pair of bytes:</span></th>
+ * </tr>
+ * <tr>
+ * <td></td>
+ * <th colspan="8" id="bit_b">Bit Values</th>
+ * </tr>
+ * <tr>
+ * <th id="byte1_b">Byte 1</th>
+ * <td><center>1</center>
+ * <td><center>1</center>
+ * <td><center>0</center>
+ * <td colspan="5"><center>bits 10-6</center>
+ * </tr>
+ * <tr>
+ * <th id="byte2_a">Byte 2</th>
+ * <td><center>1</center>
+ * <td><center>0</center>
+ * <td colspan="6"><center>bits 5-0</center>
+ * </tr>
+ * <tr>
+ * <th colspan="9"><span style="font-weight:normal">
+ * {@code char} values in the range {@code '\u005Cu0800'}
+ * to {@code '\u005CuFFFF'} are represented by three bytes:</span></th>
+ * </tr>
+ * <tr>
+ * <td></td>
+ * <th colspan="8"id="bit_c">Bit Values</th>
+ * </tr>
+ * <tr>
+ * <th id="byte1_c">Byte 1</th>
+ * <td><center>1</center>
+ * <td><center>1</center>
+ * <td><center>1</center>
+ * <td><center>0</center>
+ * <td colspan="4"><center>bits 15-12</center>
+ * </tr>
+ * <tr>
+ * <th id="byte2_b">Byte 2</th>
+ * <td><center>1</center>
+ * <td><center>0</center>
+ * <td colspan="6"><center>bits 11-6</center>
+ * </tr>
+ * <tr>
+ * <th id="byte3">Byte 3</th>
+ * <td><center>1</center>
+ * <td><center>0</center>
+ * <td colspan="6"><center>bits 5-0</center>
+ * </tr>
+ * </table>
+ * </blockquote>
+ * <p>
+ * The differences between this format and the
+ * standard UTF-8 format are the following:
+ * <ul>
+ * <li>The null byte {@code '\u005Cu0000'} is encoded in 2-byte format
+ * rather than 1-byte, so that the encoded strings never have
+ * embedded nulls.
+ * <li>Only the 1-byte, 2-byte, and 3-byte formats are used.
+ * <li><a href="../lang/Character.html#unicode">Supplementary characters</a>
+ * are represented in the form of surrogate pairs.
+ * </ul>
+ * @author Frank Yellin
+ * @see java.io.DataInputStream
+ * @see java.io.DataOutput
+ * @since 1.0
+ */
+public
+interface DataInput {
+ /**
+ * Reads some bytes from an input
+ * stream and stores them into the buffer
+ * array {@code b}. The number of bytes
+ * read is equal
+ * to the length of {@code b}.
+ * <p>
+ * This method blocks until one of the
+ * following conditions occurs:
+ * <ul>
+ * <li>{@code b.length}
+ * bytes of input data are available, in which
+ * case a normal return is made.
+ *
+ * <li>End of
+ * file is detected, in which case an {@code EOFException}
+ * is thrown.
+ *
+ * <li>An I/O error occurs, in
+ * which case an {@code IOException} other
+ * than {@code EOFException} is thrown.
+ * </ul>
+ * <p>
+ * If {@code b} is {@code null},
+ * a {@code NullPointerException} is thrown.
+ * If {@code b.length} is zero, then
+ * no bytes are read. Otherwise, the first
+ * byte read is stored into element {@code b[0]},
+ * the next one into {@code b[1]}, and
+ * so on.
+ * If an exception is thrown from
+ * this method, then it may be that some but
+ * not all bytes of {@code b} have been
+ * updated with data from the input stream.
+ *
+ * @param b the buffer into which the data is read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ void readFully(byte b[]) throws IOException;
+
+ /**
+ *
+ * Reads {@code len}
+ * bytes from
+ * an input stream.
+ * <p>
+ * This method
+ * blocks until one of the following conditions
+ * occurs:
+ * <ul>
+ * <li>{@code len} bytes
+ * of input data are available, in which case
+ * a normal return is made.
+ *
+ * <li>End of file
+ * is detected, in which case an {@code EOFException}
+ * is thrown.
+ *
+ * <li>An I/O error occurs, in
+ * which case an {@code IOException} other
+ * than {@code EOFException} is thrown.
+ * </ul>
+ * <p>
+ * If {@code b} is {@code null},
+ * a {@code NullPointerException} is thrown.
+ * If {@code off} is negative, or {@code len}
+ * is negative, or {@code off+len} is
+ * greater than the length of the array {@code b},
+ * then an {@code IndexOutOfBoundsException}
+ * is thrown.
+ * If {@code len} is zero,
+ * then no bytes are read. Otherwise, the first
+ * byte read is stored into element {@code b[off]},
+ * the next one into {@code b[off+1]},
+ * and so on. The number of bytes read is,
+ * at most, equal to {@code len}.
+ *
+ * @param b the buffer into which the data is read.
+ * @param off an int specifying the offset into the data.
+ * @param len an int specifying the number of bytes to read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ void readFully(byte b[], int off, int len) throws IOException;
+
+ /**
+ * Makes an attempt to skip over
+ * {@code n} bytes
+ * of data from the input
+ * stream, discarding the skipped bytes. However,
+ * it may skip
+ * over some smaller number of
+ * bytes, possibly zero. This may result from
+ * any of a
+ * number of conditions; reaching
+ * end of file before {@code n} bytes
+ * have been skipped is
+ * only one possibility.
+ * This method never throws an {@code EOFException}.
+ * The actual
+ * number of bytes skipped is returned.
+ *
+ * @param n the number of bytes to be skipped.
+ * @return the number of bytes actually skipped.
+ * @exception IOException if an I/O error occurs.
+ */
+ int skipBytes(int n) throws IOException;
+
+ /**
+ * Reads one input byte and returns
+ * {@code true} if that byte is nonzero,
+ * {@code false} if that byte is zero.
+ * This method is suitable for reading
+ * the byte written by the {@code writeBoolean}
+ * method of interface {@code DataOutput}.
+ *
+ * @return the {@code boolean} value read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ boolean readBoolean() throws IOException;
+
+ /**
+ * Reads and returns one input byte.
+ * The byte is treated as a signed value in
+ * the range {@code -128} through {@code 127},
+ * inclusive.
+ * This method is suitable for
+ * reading the byte written by the {@code writeByte}
+ * method of interface {@code DataOutput}.
+ *
+ * @return the 8-bit value read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ byte readByte() throws IOException;
+
+ /**
+ * Reads one input byte, zero-extends
+ * it to type {@code int}, and returns
+ * the result, which is therefore in the range
+ * {@code 0}
+ * through {@code 255}.
+ * This method is suitable for reading
+ * the byte written by the {@code writeByte}
+ * method of interface {@code DataOutput}
+ * if the argument to {@code writeByte}
+ * was intended to be a value in the range
+ * {@code 0} through {@code 255}.
+ *
+ * @return the unsigned 8-bit value read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ int readUnsignedByte() throws IOException;
+
+ /**
+ * Reads two input bytes and returns
+ * a {@code short} value. Let {@code a}
+ * be the first byte read and {@code b}
+ * be the second byte. The value
+ * returned
+ * is:
+ * <pre>{@code (short)((a << 8) | (b & 0xff))
+ * }</pre>
+ * This method
+ * is suitable for reading the bytes written
+ * by the {@code writeShort} method of
+ * interface {@code DataOutput}.
+ *
+ * @return the 16-bit value read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ short readShort() throws IOException;
+
+ /**
+ * Reads two input bytes and returns
+ * an {@code int} value in the range {@code 0}
+ * through {@code 65535}. Let {@code a}
+ * be the first byte read and
+ * {@code b}
+ * be the second byte. The value returned is:
+ * <pre>{@code (((a & 0xff) << 8) | (b & 0xff))
+ * }</pre>
+ * This method is suitable for reading the bytes
+ * written by the {@code writeShort} method
+ * of interface {@code DataOutput} if
+ * the argument to {@code writeShort}
+ * was intended to be a value in the range
+ * {@code 0} through {@code 65535}.
+ *
+ * @return the unsigned 16-bit value read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ int readUnsignedShort() throws IOException;
+
+ /**
+ * Reads two input bytes and returns a {@code char} value.
+ * Let {@code a}
+ * be the first byte read and {@code b}
+ * be the second byte. The value
+ * returned is:
+ * <pre>{@code (char)((a << 8) | (b & 0xff))
+ * }</pre>
+ * This method
+ * is suitable for reading bytes written by
+ * the {@code writeChar} method of interface
+ * {@code DataOutput}.
+ *
+ * @return the {@code char} value read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ char readChar() throws IOException;
+
+ /**
+ * Reads four input bytes and returns an
+ * {@code int} value. Let {@code a-d}
+ * be the first through fourth bytes read. The value returned is:
+ * <pre>{@code
+ * (((a & 0xff) << 24) | ((b & 0xff) << 16) |
+ * ((c & 0xff) << 8) | (d & 0xff))
+ * }</pre>
+ * This method is suitable
+ * for reading bytes written by the {@code writeInt}
+ * method of interface {@code DataOutput}.
+ *
+ * @return the {@code int} value read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ int readInt() throws IOException;
+
+ /**
+ * Reads eight input bytes and returns
+ * a {@code long} value. Let {@code a-h}
+ * be the first through eighth bytes read.
+ * The value returned is:
+ * <pre>{@code
+ * (((long)(a & 0xff) << 56) |
+ * ((long)(b & 0xff) << 48) |
+ * ((long)(c & 0xff) << 40) |
+ * ((long)(d & 0xff) << 32) |
+ * ((long)(e & 0xff) << 24) |
+ * ((long)(f & 0xff) << 16) |
+ * ((long)(g & 0xff) << 8) |
+ * ((long)(h & 0xff)))
+ * }</pre>
+ * <p>
+ * This method is suitable
+ * for reading bytes written by the {@code writeLong}
+ * method of interface {@code DataOutput}.
+ *
+ * @return the {@code long} value read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ long readLong() throws IOException;
+
+ /**
+ * Reads four input bytes and returns
+ * a {@code float} value. It does this
+ * by first constructing an {@code int}
+ * value in exactly the manner
+ * of the {@code readInt}
+ * method, then converting this {@code int}
+ * value to a {@code float} in
+ * exactly the manner of the method {@code Float.intBitsToFloat}.
+ * This method is suitable for reading
+ * bytes written by the {@code writeFloat}
+ * method of interface {@code DataOutput}.
+ *
+ * @return the {@code float} value read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ float readFloat() throws IOException;
+
+ /**
+ * Reads eight input bytes and returns
+ * a {@code double} value. It does this
+ * by first constructing a {@code long}
+ * value in exactly the manner
+ * of the {@code readLong}
+ * method, then converting this {@code long}
+ * value to a {@code double} in exactly
+ * the manner of the method {@code Double.longBitsToDouble}.
+ * This method is suitable for reading
+ * bytes written by the {@code writeDouble}
+ * method of interface {@code DataOutput}.
+ *
+ * @return the {@code double} value read.
+ * @exception EOFException if this stream reaches the end before reading
+ * all the bytes.
+ * @exception IOException if an I/O error occurs.
+ */
+ double readDouble() throws IOException;
+
+ /**
+ * Reads the next line of text from the input stream.
+ * It reads successive bytes, converting
+ * each byte separately into a character,
+ * until it encounters a line terminator or
+ * end of
+ * file; the characters read are then
+ * returned as a {@code String}. Note
+ * that because this
+ * method processes bytes,
+ * it does not support input of the full Unicode
+ * character set.
+ * <p>
+ * If end of file is encountered
+ * before even one byte can be read, then {@code null}
+ * is returned. Otherwise, each byte that is
+ * read is converted to type {@code char}
+ * by zero-extension. If the character {@code '\n'}
+ * is encountered, it is discarded and reading
+ * ceases. If the character {@code '\r'}
+ * is encountered, it is discarded and, if
+ * the following byte converts  to the
+ * character {@code '\n'}, then that is
+ * discarded also; reading then ceases. If
+ * end of file is encountered before either
+ * of the characters {@code '\n'} and
+ * {@code '\r'} is encountered, reading
+ * ceases. Once reading has ceased, a {@code String}
+ * is returned that contains all the characters
+ * read and not discarded, taken in order.
+ * Note that every character in this string
+ * will have a value less than {@code \u005Cu0100},
+ * that is, {@code (char)256}.
+ *
+ * @return the next line of text from the input stream,
+ * or {@code null} if the end of file is
+ * encountered before a byte can be read.
+ * @exception IOException if an I/O error occurs.
+ */
+ String readLine() throws IOException;
+
+ /**
+ * Reads in a string that has been encoded using a
+ * <a href="#modified-utf-8">modified UTF-8</a>
+ * format.
+ * The general contract of {@code readUTF}
+ * is that it reads a representation of a Unicode
+ * character string encoded in modified
+ * UTF-8 format; this string of characters
+ * is then returned as a {@code String}.
+ * <p>
+ * First, two bytes are read and used to
+ * construct an unsigned 16-bit integer in
+ * exactly the manner of the {@code readUnsignedShort}
+ * method . This integer value is called the
+ * <i>UTF length</i> and specifies the number
+ * of additional bytes to be read. These bytes
+ * are then converted to characters by considering
+ * them in groups. The length of each group
+ * is computed from the value of the first
+ * byte of the group. The byte following a
+ * group, if any, is the first byte of the
+ * next group.
+ * <p>
+ * If the first byte of a group
+ * matches the bit pattern {@code 0xxxxxxx}
+ * (where {@code x} means "may be {@code 0}
+ * or {@code 1}"), then the group consists
+ * of just that byte. The byte is zero-extended
+ * to form a character.
+ * <p>
+ * If the first byte
+ * of a group matches the bit pattern {@code 110xxxxx},
+ * then the group consists of that byte {@code a}
+ * and a second byte {@code b}. If there
+ * is no byte {@code b} (because byte
+ * {@code a} was the last of the bytes
+ * to be read), or if byte {@code b} does
+ * not match the bit pattern {@code 10xxxxxx},
+ * then a {@code UTFDataFormatException}
+ * is thrown. Otherwise, the group is converted
+ * to the character:
+ * <pre>{@code (char)(((a & 0x1F) << 6) | (b & 0x3F))
+ * }</pre>
+ * If the first byte of a group
+ * matches the bit pattern {@code 1110xxxx},
+ * then the group consists of that byte {@code a}
+ * and two more bytes {@code b} and {@code c}.
+ * If there is no byte {@code c} (because
+ * byte {@code a} was one of the last
+ * two of the bytes to be read), or either
+ * byte {@code b} or byte {@code c}
+ * does not match the bit pattern {@code 10xxxxxx},
+ * then a {@code UTFDataFormatException}
+ * is thrown. Otherwise, the group is converted
+ * to the character:
+ * <pre>{@code
+ * (char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))
+ * }</pre>
+ * If the first byte of a group matches the
+ * pattern {@code 1111xxxx} or the pattern
+ * {@code 10xxxxxx}, then a {@code UTFDataFormatException}
+ * is thrown.
+ * <p>
+ * If end of file is encountered
+ * at any time during this entire process,
+ * then an {@code EOFException} is thrown.
+ * <p>
+ * After every group has been converted to
+ * a character by this process, the characters
+ * are gathered, in the same order in which
+ * their corresponding groups were read from
+ * the input stream, to form a {@code String},
+ * which is returned.
+ * <p>
+ * The {@code writeUTF}
+ * method of interface {@code DataOutput}
+ * may be used to write data that is suitable
+ * for reading by this method.
+ * @return a Unicode string.
+ * @exception EOFException if this stream reaches the end
+ * before reading all the bytes.
+ * @exception IOException if an I/O error occurs.
+ * @exception UTFDataFormatException if the bytes do not represent a
+ * valid modified UTF-8 encoding of a string.
+ */
+ String readUTF() throws IOException;
+}