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 * Copyright (c) 1999, 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,
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 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package javax.imageio.stream;

import java.io.Closeable;
import java.io.DataInput;
import java.io.IOException;
import java.nio.ByteOrder;


A seekable input stream interface for use by
ImageReaders.  Various input sources, such as
InputStreams and Files,
as well as future fast I/O sources may be "wrapped" by a suitable
implementation of this interface for use by the Image I/O API.

See Also:
/**
 * A seekable input stream interface for use by
 * <code>ImageReader</code>s.  Various input sources, such as
 * <code>InputStream</code>s and <code>File</code>s,
 * as well as future fast I/O sources may be "wrapped" by a suitable
 * implementation of this interface for use by the Image I/O API.
 *
 * @see ImageInputStreamImpl
 * @see FileImageInputStream
 * @see FileCacheImageInputStream
 * @see MemoryCacheImageInputStream
 *
 */
public interface ImageInputStream extends DataInput, Closeable {

    
Sets the desired byte order for future reads of data values
from this stream.  For example, the sequence of bytes '0x01
0x02 0x03 0x04' if read as a 4-byte integer would have the
value '0x01020304' using network byte order and the value
'0x04030201' under the reverse byte order.

 The enumeration class java.nio.ByteOrder is
used to specify the byte order.  A value of
ByteOrder.BIG_ENDIAN specifies so-called
big-endian or network byte order, in which the high-order byte
comes first.  Motorola and Sparc processors store data in this
format, while Intel processors store data in the reverse
ByteOrder.LITTLE_ENDIAN order.

 The byte order has no effect on the results returned from
the readBits method (or the value written by
ImageOutputStream.writeBits).

Params:
  • byteOrder – one of ByteOrder.BIG_ENDIAN or
java.nio.ByteOrder.LITTLE_ENDIAN, indicating whether
network byte order or its reverse will be used for future
reads.
See Also:
/**
     * Sets the desired byte order for future reads of data values
     * from this stream.  For example, the sequence of bytes '0x01
     * 0x02 0x03 0x04' if read as a 4-byte integer would have the
     * value '0x01020304' using network byte order and the value
     * '0x04030201' under the reverse byte order.
     *
     * <p> The enumeration class <code>java.nio.ByteOrder</code> is
     * used to specify the byte order.  A value of
     * <code>ByteOrder.BIG_ENDIAN</code> specifies so-called
     * big-endian or network byte order, in which the high-order byte
     * comes first.  Motorola and Sparc processors store data in this
     * format, while Intel processors store data in the reverse
     * <code>ByteOrder.LITTLE_ENDIAN</code> order.
     *
     * <p> The byte order has no effect on the results returned from
     * the <code>readBits</code> method (or the value written by
     * <code>ImageOutputStream.writeBits</code>).
     *
     * @param byteOrder one of <code>ByteOrder.BIG_ENDIAN</code> or
     * <code>java.nio.ByteOrder.LITTLE_ENDIAN</code>, indicating whether
     * network byte order or its reverse will be used for future
     * reads.
     *
     * @see java.nio.ByteOrder
     * @see #getByteOrder
     * @see #readBits(int)
     */
    void setByteOrder(ByteOrder byteOrder);

    
Returns the byte order with which data values will be read from
this stream as an instance of the
java.nio.ByteOrder enumeration.

See Also:
Returns:one of ByteOrder.BIG_ENDIAN or
ByteOrder.LITTLE_ENDIAN, indicating which byte
order is being used.
/**
     * Returns the byte order with which data values will be read from
     * this stream as an instance of the
     * <code>java.nio.ByteOrder</code> enumeration.
     *
     * @return one of <code>ByteOrder.BIG_ENDIAN</code> or
     * <code>ByteOrder.LITTLE_ENDIAN</code>, indicating which byte
     * order is being used.
     *
     * @see java.nio.ByteOrder
     * @see #setByteOrder
     */
    ByteOrder getByteOrder();

    
Reads a single byte from the stream and returns it as an
integer between 0 and 255.  If the end of the stream is
reached, -1 is returned.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
Returns:a byte value from the stream, as an int, or -1 to
indicate EOF.
/**
     * Reads a single byte from the stream and returns it as an
     * integer between 0 and 255.  If the end of the stream is
     * reached, -1 is returned.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return a byte value from the stream, as an int, or -1 to
     * indicate EOF.
     *
     * @exception IOException if an I/O error occurs.
     */
    int read() throws IOException;

    
Reads up to b.length bytes from the stream, and
stores them into b starting at index 0.  The
number of bytes read is returned.  If no bytes can be read
because the end of the stream has been reached, -1 is returned.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • b – an array of bytes to be written to.
Throws:
Returns:the number of bytes actually read, or -1
to indicate EOF.
/**
     * Reads up to <code>b.length</code> bytes from the stream, and
     * stores them into <code>b</code> starting at index 0.  The
     * number of bytes read is returned.  If no bytes can be read
     * because the end of the stream has been reached, -1 is returned.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param b an array of bytes to be written to.
     *
     * @return the number of bytes actually read, or <code>-1</code>
     * to indicate EOF.
     *
     * @exception NullPointerException if <code>b</code> is
     * <code>null</code>.
     *
     * @exception IOException if an I/O error occurs.
     */
    int read(byte[] b) throws IOException;

    
Reads up to len bytes from the stream, and stores
them into b starting at index off.
The number of bytes read is returned.  If no bytes can be read
because the end of the stream has been reached, -1
is returned.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • b – an array of bytes to be written to.
  • off – the starting position within b to write to.
  • len – the maximum number of bytes to read.
Throws:
Returns:the number of bytes actually read, or -1
to indicate EOF.
/**
     * Reads up to <code>len</code> bytes from the stream, and stores
     * them into <code>b</code> starting at index <code>off</code>.
     * The number of bytes read is returned.  If no bytes can be read
     * because the end of the stream has been reached, <code>-1</code>
     * is returned.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param b an array of bytes to be written to.
     * @param off the starting position within <code>b</code> to write to.
     * @param len the maximum number of <code>byte</code>s to read.
     *
     * @return the number of bytes actually read, or <code>-1</code>
     * to indicate EOF.
     *
     * @exception NullPointerException if <code>b</code> is
     * <code>null</code>.
     * @exception IndexOutOfBoundsException if <code>off</code> is
     * negative, <code>len</code> is negative, or <code>off +
     * len</code> is greater than <code>b.length</code>.
     * @exception IOException if an I/O error occurs.
     */
    int read(byte[] b, int off, int len) throws IOException;

    
Reads up to len bytes from the stream, and
modifies the supplied IIOByteBuffer to indicate
the byte array, offset, and length where the data may be found.
The caller should not attempt to modify the data found in the
IIOByteBuffer.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • buf – an IIOByteBuffer object to be modified.
  • len – the maximum number of bytes to read.
Throws:
/**
     * Reads up to <code>len</code> bytes from the stream, and
     * modifies the supplied <code>IIOByteBuffer</code> to indicate
     * the byte array, offset, and length where the data may be found.
     * The caller should not attempt to modify the data found in the
     * <code>IIOByteBuffer</code>.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param buf an IIOByteBuffer object to be modified.
     * @param len the maximum number of <code>byte</code>s to read.
     *
     * @exception IndexOutOfBoundsException if <code>len</code> is
     * negative.
     * @exception NullPointerException if <code>buf</code> is
     * <code>null</code>.
     *
     * @exception IOException if an I/O error occurs.
     */
    void readBytes(IIOByteBuffer buf, int len) throws IOException;

    
Reads a byte from the stream and returns a boolean
value of true if it is nonzero, false
if it is zero.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
Returns:a boolean value from the stream.
/**
     * Reads a byte from the stream and returns a <code>boolean</code>
     * value of <code>true</code> if it is nonzero, <code>false</code>
     * if it is zero.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return a boolean value from the stream.
     *
     * @exception java.io.EOFException if the end of the stream is reached.
     * @exception IOException if an I/O error occurs.
     */
    boolean readBoolean() throws IOException;

    
Reads a byte from the stream and returns it as a
byte value.  Byte values between 0x00
and 0x7f represent integer values between
0 and 127.  Values between
0x80 and 0xff represent negative
values from -128 to /1.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
Returns:a signed byte value from the stream.
/**
     * Reads a byte from the stream and returns it as a
     * <code>byte</code> value.  Byte values between <code>0x00</code>
     * and <code>0x7f</code> represent integer values between
     * <code>0</code> and <code>127</code>.  Values between
     * <code>0x80</code> and <code>0xff</code> represent negative
     * values from <code>-128</code> to <code>/1</code>.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return a signed byte value from the stream.
     *
     * @exception java.io.EOFException if the end of the stream is reached.
     * @exception IOException if an I/O error occurs.
     */
    byte readByte() throws IOException;

    
Reads a byte from the stream, and (conceptually) converts it to
an int, masks it with 0xff in order to strip off
any sign-extension bits, and returns it as a byte
value.

 Thus, byte values between 0x00 and
0x7f are simply returned as integer values between
0 and 127.  Values between
0x80 and 0xff, which normally
represent negative bytevalues, will be mapped into
positive integers between 128 and
255.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
Returns:an unsigned byte value from the stream.
/**
     * Reads a byte from the stream, and (conceptually) converts it to
     * an int, masks it with <code>0xff</code> in order to strip off
     * any sign-extension bits, and returns it as a <code>byte</code>
     * value.
     *
     * <p> Thus, byte values between <code>0x00</code> and
     * <code>0x7f</code> are simply returned as integer values between
     * <code>0</code> and <code>127</code>.  Values between
     * <code>0x80</code> and <code>0xff</code>, which normally
     * represent negative <code>byte</code>values, will be mapped into
     * positive integers between <code>128</code> and
     * <code>255</code>.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return an unsigned byte value from the stream.
     *
     * @exception java.io.EOFException if the end of the stream is reached.
     * @exception IOException if an I/O error occurs.
     */
    int readUnsignedByte() throws IOException;

    
Reads two bytes from the stream, and (conceptually)
concatenates them according to the current byte order, and
returns the result as a short value.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
  • EOFException – if the stream reaches the end before
reading all the bytes.
  • IOException – if an I/O error occurs.
See Also:
Returns:a signed short value from the stream.
/**
     * Reads two bytes from the stream, and (conceptually)
     * concatenates them according to the current byte order, and
     * returns the result as a <code>short</code> value.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return a signed short value from the stream.
     *
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     *
     * @see #getByteOrder
     */
    short readShort() throws IOException;

    
Reads two bytes from the stream, and (conceptually)
concatenates them according to the current byte order, converts
the resulting value to an int, masks it with
0xffff in order to strip off any sign-extension
buts, and returns the result as an unsigned int
value.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
  • EOFException – if the stream reaches the end before
reading all the bytes.
  • IOException – if an I/O error occurs.
See Also:
Returns:an unsigned short value from the stream, as an int.
/**
     * Reads two bytes from the stream, and (conceptually)
     * concatenates them according to the current byte order, converts
     * the resulting value to an <code>int</code>, masks it with
     * <code>0xffff</code> in order to strip off any sign-extension
     * buts, and returns the result as an unsigned <code>int</code>
     * value.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return an unsigned short value from the stream, as an int.
     *
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     *
     * @see #getByteOrder
     */
    int readUnsignedShort() throws IOException;

    
Equivalent to readUnsignedShort, except that the
result is returned using the char datatype.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
  • EOFException – if the stream reaches the end before
reading all the bytes.
  • IOException – if an I/O error occurs.
See Also:
Returns:an unsigned char value from the stream.
/**
     * Equivalent to <code>readUnsignedShort</code>, except that the
     * result is returned using the <code>char</code> datatype.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return an unsigned char value from the stream.
     *
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     *
     * @see #readUnsignedShort
     */
    char readChar() throws IOException;

    
Reads 4 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as an int.

 The bit offset within the stream is ignored and treated as
though it were zero.

Throws:
  • EOFException – if the stream reaches the end before
reading all the bytes.
  • IOException – if an I/O error occurs.
See Also:
Returns:a signed int value from the stream.
/**
     * Reads 4 bytes from the stream, and (conceptually) concatenates
     * them according to the current byte order and returns the result
     * as an <code>int</code>.
     *
     * <p> The bit offset within the stream is ignored and treated as
     * though it were zero.
     *
     * @return a signed int value from the stream.
     *
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     *
     * @see #getByteOrder
     */
    int readInt() throws IOException;

    
Reads 4 bytes from the stream, and (conceptually) concatenates
them according to the current byte order, converts the result
to a long, masks it with 0xffffffffL in order to
strip off any sign-extension bits, and returns the result as an
unsigned long value.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
  • EOFException – if the stream reaches the end before
reading all the bytes.
  • IOException – if an I/O error occurs.
See Also:
Returns:an unsigned int value from the stream, as a long.
/**
     * Reads 4 bytes from the stream, and (conceptually) concatenates
     * them according to the current byte order, converts the result
     * to a long, masks it with <code>0xffffffffL</code> in order to
     * strip off any sign-extension bits, and returns the result as an
     * unsigned <code>long</code> value.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return an unsigned int value from the stream, as a long.
     *
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     *
     * @see #getByteOrder
     */
    long readUnsignedInt() throws IOException;

    
Reads 8 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as a long.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
  • EOFException – if the stream reaches the end before
reading all the bytes.
  • IOException – if an I/O error occurs.
See Also:
Returns:a signed long value from the stream.
/**
     * Reads 8 bytes from the stream, and (conceptually) concatenates
     * them according to the current byte order and returns the result
     * as a <code>long</code>.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return a signed long value from the stream.
     *
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     *
     * @see #getByteOrder
     */
    long readLong() throws IOException;

    
Reads 4 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as a float.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
  • EOFException – if the stream reaches the end before
reading all the bytes.
  • IOException – if an I/O error occurs.
See Also:
Returns:a float value from the stream.
/**
     * Reads 4 bytes from the stream, and (conceptually) concatenates
     * them according to the current byte order and returns the result
     * as a <code>float</code>.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return a float value from the stream.
     *
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     *
     * @see #getByteOrder
     */
    float readFloat() throws IOException;

    
Reads 8 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as a double.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
  • EOFException – if the stream reaches the end before
reading all the bytes.
  • IOException – if an I/O error occurs.
See Also:
Returns:a double value from the stream.
/**
     * Reads 8 bytes from the stream, and (conceptually) concatenates
     * them according to the current byte order and returns the result
     * as a <code>double</code>.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return a double value from the stream.
     *
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     *
     * @see #getByteOrder
     */
    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
String. Note that because this method processes
bytes, it does not support input of the full Unicode character
set.

 If end of file is encountered before even one byte can be
read, then null is returned. Otherwise, each byte
that is read is converted to type char by
zero-extension. If the character '\n' is
encountered, it is discarded and reading ceases. If the
character '\r' is encountered, it is discarded
and, if the following byte converts  to the character
'\n', then that is discarded also; reading then
ceases. If end of file is encountered before either of the
characters '\n' and '\r' is
encountered, reading ceases. Once reading has ceased, a
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
\u0100, that is, (char)256.

 The bit offset within the stream is reset to zero before
the read occurs.

Throws:
Returns:a String containing a line of text from the stream.
/**
     * 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</code>. 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</code> is returned. Otherwise, each byte
     * that is read is converted to type <code>char</code> by
     * zero-extension. If the character <code>'\n'</code> is
     * encountered, it is discarded and reading ceases. If the
     * character <code>'\r'</code> is encountered, it is discarded
     * and, if the following byte converts &#32;to the character
     * <code>'\n'</code>, then that is discarded also; reading then
     * ceases. If end of file is encountered before either of the
     * characters <code>'\n'</code> and <code>'\r'</code> is
     * encountered, reading ceases. Once reading has ceased, a
     * <code>String</code> 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>&#92;u0100</code>, that is, <code>(char)256</code>.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @return a String containing a line of text from the stream.
     *
     * @exception IOException if an I/O error occurs.
     */
    String readLine() throws IOException;

    
Reads in a string that has been encoded using a
modified
UTF-8
format.  The general contract of 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 String.

 First, two bytes are read and used to construct an unsigned
16-bit integer in the manner of the
readUnsignedShort method, using network byte order
(regardless of the current byte order setting). This integer
value is called the UTF length 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.

 If the first byte of a group matches the bit pattern
0xxxxxxx (where x means "may be
0 or 1"), then the group consists of
just that byte. The byte is zero-extended to form a character.

 If the first byte of a group matches the bit pattern
110xxxxx, then the group consists of that byte
a and a second byte b. If there is no
byte b (because byte a was the last
of the bytes to be read), or if byte b does not
match the bit pattern 10xxxxxx, then a
UTFDataFormatException is thrown. Otherwise, the
group is converted to the character:

 

(char)(((a& 0x1F) << 6) | (b & 0x3F))


If the first byte of a group matches the bit pattern
1110xxxx, then the group consists of that byte
a and two more bytes b and
c.  If there is no byte c (because
byte a was one of the last two of the bytes to be
read), or either byte b or byte c
does not match the bit pattern 10xxxxxx, then a
UTFDataFormatException is thrown. Otherwise, the
group is converted to the character:

 

(char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))


If the first byte of a group matches the pattern
1111xxxx or the pattern 10xxxxxx,
then a UTFDataFormatException is thrown.

 If end of file is encountered at any time during this
entire process, then an java.io.EOFException is thrown.

 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 String, which is returned.

 The current byte order setting is ignored.

 The bit offset within the stream is reset to zero before
the read occurs.

Note: This method should not be used in
the  implementation of image formats that use standard UTF-8,
because  the modified UTF-8 used here is incompatible with
standard UTF-8.

Throws:
Returns:a String read from the stream.
/**
     * Reads in a string that has been encoded using a
     * <a href="../../../java/io/DataInput.html#modified-utf-8">modified
     * UTF-8</a>
     * format.  The general contract of <code>readUTF</code> 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</code>.
     *
     * <p> First, two bytes are read and used to construct an unsigned
     * 16-bit integer in the manner of the
     * <code>readUnsignedShort</code> method, using network byte order
     * (regardless of the current byte order setting). 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</code> (where <code>x</code> means "may be
     * <code>0</code> or <code>1</code>"), 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</code>, then the group consists of that byte
     * <code>a</code> and a second byte <code>b</code>. If there is no
     * byte <code>b</code> (because byte <code>a</code> was the last
     * of the bytes to be read), or if byte <code>b</code> does not
     * match the bit pattern <code>10xxxxxx</code>, then a
     * <code>UTFDataFormatException</code> is thrown. Otherwise, the
     * group is converted to the character:
     *
     * <p> <pre><code>
     * (char)(((a&amp; 0x1F) &lt;&lt; 6) | (b &amp; 0x3F))
     * </code></pre>
     *
     * If the first byte of a group matches the bit pattern
     * <code>1110xxxx</code>, then the group consists of that byte
     * <code>a</code> and two more bytes <code>b</code> and
     * <code>c</code>.  If there is no byte <code>c</code> (because
     * byte <code>a</code> was one of the last two of the bytes to be
     * read), or either byte <code>b</code> or byte <code>c</code>
     * does not match the bit pattern <code>10xxxxxx</code>, then a
     * <code>UTFDataFormatException</code> is thrown. Otherwise, the
     * group is converted to the character:
     *
     * <p> <pre><code>
     * (char)(((a &amp; 0x0F) &lt;&lt; 12) | ((b &amp; 0x3F) &lt;&lt; 6) | (c &amp; 0x3F))
     * </code></pre>
     *
     * If the first byte of a group matches the pattern
     * <code>1111xxxx</code> or the pattern <code>10xxxxxx</code>,
     * then a <code>UTFDataFormatException</code> is thrown.
     *
     * <p> If end of file is encountered at any time during this
     * entire process, then an <code>java.io.EOFException</code> 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</code>, which is returned.
     *
     * <p> The current byte order setting is ignored.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * <p><strong>Note:</strong> This method should not be used in
     * the  implementation of image formats that use standard UTF-8,
     * because  the modified UTF-8 used here is incompatible with
     * standard UTF-8.
     *
     * @return a String read from the stream.
     *
     * @exception  java.io.EOFException  if this stream reaches the end
     * before reading all the bytes.
     * @exception  java.io.UTFDataFormatException if the bytes do not represent
     * a valid modified UTF-8 encoding of a string.
     * @exception IOException if an I/O error occurs.
     */
    String readUTF() throws IOException;

    
Reads len bytes from the stream, and stores them
into b starting at index off.
If the end of the stream is reached, an java.io.EOFException
will be thrown.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • b – an array of bytes to be written to.
  • off – the starting position within b to write to.
  • len – the maximum number of bytes to read.
Throws:
/**
     * Reads <code>len</code> bytes from the stream, and stores them
     * into <code>b</code> starting at index <code>off</code>.
     * If the end of the stream is reached, an <code>java.io.EOFException</code>
     * will be thrown.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param b an array of bytes to be written to.
     * @param off the starting position within <code>b</code> to write to.
     * @param len the maximum number of <code>byte</code>s to read.
     *
     * @exception IndexOutOfBoundsException if <code>off</code> is
     * negative, <code>len</code> is negative, or <code>off +
     * len</code> is greater than <code>b.length</code>.
     * @exception NullPointerException if <code>b</code> is
     * <code>null</code>.
     * @exception java.io.EOFException if the 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;

    
Reads b.length bytes from the stream, and stores them
into b starting at index 0.
If the end of the stream is reached, an java.io.EOFException
will be thrown.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • b – an array of bytes.
Throws:
/**
     * Reads <code>b.length</code> bytes from the stream, and stores them
     * into <code>b</code> starting at index <code>0</code>.
     * If the end of the stream is reached, an <code>java.io.EOFException</code>
     * will be thrown.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param b an array of <code>byte</code>s.
     *
     * @exception NullPointerException if <code>b</code> is
     * <code>null</code>.
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     */
    void readFully(byte[] b) throws IOException;

    
Reads len shorts (signed 16-bit integers) from the
stream according to the current byte order, and
stores them into s starting at index
off.  If the end of the stream is reached, an
java.io.EOFException will be thrown.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • s – an array of shorts to be written to.
  • off – the starting position within s to write to.
  • len – the maximum number of shorts to read.
Throws:
/**
     * Reads <code>len</code> shorts (signed 16-bit integers) from the
     * stream according to the current byte order, and
     * stores them into <code>s</code> starting at index
     * <code>off</code>.  If the end of the stream is reached, an
     * <code>java.io.EOFException</code> will be thrown.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param s an array of shorts to be written to.
     * @param off the starting position within <code>s</code> to write to.
     * @param len the maximum number of <code>short</code>s to read.
     *
     * @exception IndexOutOfBoundsException if <code>off</code> is
     * negative, <code>len</code> is negative, or <code>off +
     * len</code> is greater than <code>s.length</code>.
     * @exception NullPointerException if <code>s</code> is
     * <code>null</code>.
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     */
    void readFully(short[] s, int off, int len) throws IOException;

    
Reads len chars (unsigned 16-bit integers) from the
stream according to the current byte order, and
stores them into c starting at index
off.  If the end of the stream is reached, an
java.io.EOFException will be thrown.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • c – an array of chars to be written to.
  • off – the starting position within c to write to.
  • len – the maximum number of chars to read.
Throws:
/**
     * Reads <code>len</code> chars (unsigned 16-bit integers) from the
     * stream according to the current byte order, and
     * stores them into <code>c</code> starting at index
     * <code>off</code>.  If the end of the stream is reached, an
     * <code>java.io.EOFException</code> will be thrown.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param c an array of chars to be written to.
     * @param off the starting position within <code>c</code> to write to.
     * @param len the maximum number of <code>char</code>s to read.
     *
     * @exception IndexOutOfBoundsException if <code>off</code> is
     * negative, <code>len</code> is negative, or <code>off +
     * len</code> is greater than <code>c.length</code>.
     * @exception NullPointerException if <code>c</code> is
     * <code>null</code>.
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     */
    void readFully(char[] c, int off, int len) throws IOException;

    
Reads len ints (signed 32-bit integers) from the
stream according to the current byte order, and
stores them into i starting at index
off.  If the end of the stream is reached, an
java.io.EOFException will be thrown.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • i – an array of ints to be written to.
  • off – the starting position within i to write to.
  • len – the maximum number of ints to read.
Throws:
/**
     * Reads <code>len</code> ints (signed 32-bit integers) from the
     * stream according to the current byte order, and
     * stores them into <code>i</code> starting at index
     * <code>off</code>.  If the end of the stream is reached, an
     * <code>java.io.EOFException</code> will be thrown.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param i an array of ints to be written to.
     * @param off the starting position within <code>i</code> to write to.
     * @param len the maximum number of <code>int</code>s to read.
     *
     * @exception IndexOutOfBoundsException if <code>off</code> is
     * negative, <code>len</code> is negative, or <code>off +
     * len</code> is greater than <code>i.length</code>.
     * @exception NullPointerException if <code>i</code> is
     * <code>null</code>.
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     */
    void readFully(int[] i, int off, int len) throws IOException;

    
Reads len longs (signed 64-bit integers) from the
stream according to the current byte order, and
stores them into l starting at index
off.  If the end of the stream is reached, an
java.io.EOFException will be thrown.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • l – an array of longs to be written to.
  • off – the starting position within l to write to.
  • len – the maximum number of longs to read.
Throws:
/**
     * Reads <code>len</code> longs (signed 64-bit integers) from the
     * stream according to the current byte order, and
     * stores them into <code>l</code> starting at index
     * <code>off</code>.  If the end of the stream is reached, an
     * <code>java.io.EOFException</code> will be thrown.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param l an array of longs to be written to.
     * @param off the starting position within <code>l</code> to write to.
     * @param len the maximum number of <code>long</code>s to read.
     *
     * @exception IndexOutOfBoundsException if <code>off</code> is
     * negative, <code>len</code> is negative, or <code>off +
     * len</code> is greater than <code>l.length</code>.
     * @exception NullPointerException if <code>l</code> is
     * <code>null</code>.
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     */
    void readFully(long[] l, int off, int len) throws IOException;

    
Reads len floats (32-bit IEEE single-precision
floats) from the stream according to the current byte order,
and stores them into f starting at
index off.  If the end of the stream is reached,
an java.io.EOFException will be thrown.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • f – an array of floats to be written to.
  • off – the starting position within f to write to.
  • len – the maximum number of floats to read.
Throws:
/**
     * Reads <code>len</code> floats (32-bit IEEE single-precision
     * floats) from the stream according to the current byte order,
     * and stores them into <code>f</code> starting at
     * index <code>off</code>.  If the end of the stream is reached,
     * an <code>java.io.EOFException</code> will be thrown.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param f an array of floats to be written to.
     * @param off the starting position within <code>f</code> to write to.
     * @param len the maximum number of <code>float</code>s to read.
     *
     * @exception IndexOutOfBoundsException if <code>off</code> is
     * negative, <code>len</code> is negative, or <code>off +
     * len</code> is greater than <code>f.length</code>.
     * @exception NullPointerException if <code>f</code> is
     * <code>null</code>.
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     */
    void readFully(float[] f, int off, int len) throws IOException;

    
Reads len doubles (64-bit IEEE double-precision
floats) from the stream according to the current byte order,
and stores them into d starting at
index off.  If the end of the stream is reached,
an java.io.EOFException will be thrown.

 The bit offset within the stream is reset to zero before
the read occurs.

Params:
  • d – an array of doubles to be written to.
  • off – the starting position within d to write to.
  • len – the maximum number of doubles to read.
Throws:
/**
     * Reads <code>len</code> doubles (64-bit IEEE double-precision
     * floats) from the stream according to the current byte order,
     * and stores them into <code>d</code> starting at
     * index <code>off</code>.  If the end of the stream is reached,
     * an <code>java.io.EOFException</code> will be thrown.
     *
     * <p> The bit offset within the stream is reset to zero before
     * the read occurs.
     *
     * @param d an array of doubles to be written to.
     * @param off the starting position within <code>d</code> to write to.
     * @param len the maximum number of <code>double</code>s to read.
     *
     * @exception IndexOutOfBoundsException if <code>off</code> is
     * negative, <code>len</code> is negative, or <code>off +
     * len</code> is greater than <code>d.length</code>.
     * @exception NullPointerException if <code>d</code> is
     * <code>null</code>.
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bytes.
     * @exception IOException if an I/O error occurs.
     */
    void readFully(double[] d, int off, int len) throws IOException;

    
Returns the current byte position of the stream.  The next read
will take place starting at this offset.

Throws:
Returns:a long containing the position of the stream.
/**
     * Returns the current byte position of the stream.  The next read
     * will take place starting at this offset.
     *
     * @return a long containing the position of the stream.
     *
     * @exception IOException if an I/O error occurs.
     */
    long getStreamPosition() throws IOException;

    
Returns the current bit offset, as an integer between 0 and 7,
inclusive.  The bit offset is updated implicitly by calls to
the readBits method.  A value of 0 indicates the
most-significant bit, and a value of 7 indicates the least
significant bit, of the byte being read.

 The bit offset is set to 0 when a stream is first
opened, and is reset to 0 by calls to seek,
skipBytes, or any read or
readFully method.

Throws:
See Also:
Returns:an int containing the bit offset between
0 and 7, inclusive.
/**
     * Returns the current bit offset, as an integer between 0 and 7,
     * inclusive.  The bit offset is updated implicitly by calls to
     * the <code>readBits</code> method.  A value of 0 indicates the
     * most-significant bit, and a value of 7 indicates the least
     * significant bit, of the byte being read.
     *
     * <p> The bit offset is set to 0 when a stream is first
     * opened, and is reset to 0 by calls to <code>seek</code>,
     * <code>skipBytes</code>, or any <code>read</code> or
     * <code>readFully</code> method.
     *
     * @return an <code>int</code> containing the bit offset between
     * 0 and 7, inclusive.
     *
     * @exception IOException if an I/O error occurs.
     *
     * @see #setBitOffset
     */
    int getBitOffset() throws IOException;

    
Sets the bit offset to an integer between 0 and 7, inclusive.
The byte offset within the stream, as returned by
getStreamPosition, is left unchanged.
A value of 0 indicates the
most-significant bit, and a value of 7 indicates the least
significant bit, of the byte being read.

Params:
  • bitOffset – the desired offset, as an int
between 0 and 7, inclusive.
Throws:
See Also:
/**
     * Sets the bit offset to an integer between 0 and 7, inclusive.
     * The byte offset within the stream, as returned by
     * <code>getStreamPosition</code>, is left unchanged.
     * A value of 0 indicates the
     * most-significant bit, and a value of 7 indicates the least
     * significant bit, of the byte being read.
     *
     * @param bitOffset the desired offset, as an <code>int</code>
     * between 0 and 7, inclusive.
     *
     * @exception IllegalArgumentException if <code>bitOffset</code>
     * is not between 0 and 7, inclusive.
     * @exception IOException if an I/O error occurs.
     *
     * @see #getBitOffset
     */
    void setBitOffset(int bitOffset) throws IOException;

    
Reads a single bit from the stream and returns it as an
int with the value 0 or
1.  The bit offset is advanced by one and reduced
modulo 8.

Throws:
Returns:an int containing the value 0
or 1.
/**
     * Reads a single bit from the stream and returns it as an
     * <code>int</code> with the value <code>0</code> or
     * <code>1</code>.  The bit offset is advanced by one and reduced
     * modulo 8.
     *
     * @return an <code>int</code> containing the value <code>0</code>
     * or <code>1</code>.
     *
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bits.
     * @exception IOException if an I/O error occurs.
     */
    int readBit() throws IOException;

    
Reads a bitstring from the stream and returns it as a
long, with the first bit read becoming the most
significant bit of the output.  The read starts within the byte
indicated by getStreamPosition, at the bit given
by getBitOffset.  The bit offset is advanced by
numBits and reduced modulo 8.

 The byte order of the stream has no effect on this
method.  The return value of this method is constructed as
though the bits were read one at a time, and shifted into
the right side of the return value, as shown by the following
pseudo-code:


long accum = 0L;
for (int i = 0; i < numBits; i++) {
  accum <<= 1; // Shift left one bit to make room
  accum |= readBit();
 }


Note that the result of readBits(32) may thus not
be equal to that of readInt() if a reverse network
byte order is being used (i.e., getByteOrder() ==
false).

 If the end of the stream is encountered before all the bits
have been read, an java.io.EOFException is thrown.

Params:
  • numBits – the number of bits to read, as an int
between 0 and 64, inclusive.
Throws:
Returns:the bitstring, as a long with the last bit
read stored in the least significant bit.
/**
     * Reads a bitstring from the stream and returns it as a
     * <code>long</code>, with the first bit read becoming the most
     * significant bit of the output.  The read starts within the byte
     * indicated by <code>getStreamPosition</code>, at the bit given
     * by <code>getBitOffset</code>.  The bit offset is advanced by
     * <code>numBits</code> and reduced modulo 8.
     *
     * <p> The byte order of the stream has no effect on this
     * method.  The return value of this method is constructed as
     * though the bits were read one at a time, and shifted into
     * the right side of the return value, as shown by the following
     * pseudo-code:
     *
     * <pre>{@code
     * long accum = 0L;
     * for (int i = 0; i < numBits; i++) {
     *   accum <<= 1; // Shift left one bit to make room
     *   accum |= readBit();
     * }
     * }</pre>
     *
     * Note that the result of <code>readBits(32)</code> may thus not
     * be equal to that of <code>readInt()</code> if a reverse network
     * byte order is being used (i.e., <code>getByteOrder() ==
     * false</code>).
     *
     * <p> If the end of the stream is encountered before all the bits
     * have been read, an <code>java.io.EOFException</code> is thrown.
     *
     * @param numBits the number of bits to read, as an <code>int</code>
     * between 0 and 64, inclusive.
     * @return the bitstring, as a <code>long</code> with the last bit
     * read stored in the least significant bit.
     *
     * @exception IllegalArgumentException if <code>numBits</code>
     * is not between 0 and 64, inclusive.
     * @exception java.io.EOFException if the stream reaches the end before
     * reading all the bits.
     * @exception IOException if an I/O error occurs.
     */
    long readBits(int numBits) throws IOException;

    
Returns the total length of the stream, if known.  Otherwise,
-1 is returned.

Throws:
Returns:a long containing the length of the
stream, if known, or else -1.
/**
     * Returns the total length of the stream, if known.  Otherwise,
     * <code>-1</code> is returned.
     *
     * @return a <code>long</code> containing the length of the
     * stream, if known, or else <code>-1</code>.
     *
     * @exception IOException if an I/O error occurs.
     */
    long length() throws IOException;

    
Moves the stream position forward by a given number of bytes.  It
is possible that this method will only be able to skip forward
by a smaller number of bytes than requested, for example if the
end of the stream is reached.  In all cases, the actual number
of bytes skipped is returned.  The bit offset is set to zero
prior to advancing the position.

Params:
  • n – an int containing the number of bytes to
be skipped.
Throws:
Returns:an int representing the number of bytes skipped.
/**
     * Moves the stream position forward by a given number of bytes.  It
     * is possible that this method will only be able to skip forward
     * by a smaller number of bytes than requested, for example if the
     * end of the stream is reached.  In all cases, the actual number
     * of bytes skipped is returned.  The bit offset is set to zero
     * prior to advancing the position.
     *
     * @param n an <code>int</code> containing the number of bytes to
     * be skipped.
     *
     * @return an <code>int</code> representing the number of bytes skipped.
     *
     * @exception IOException if an I/O error occurs.
     */
    int skipBytes(int n) throws IOException;

    
Moves the stream position forward by a given number of bytes.
This method is identical to skipBytes(int) except
that it allows for a larger skip distance.

Params:
  • n – a long containing the number of bytes to
be skipped.
Throws:
Returns:a long representing the number of bytes
skipped.
/**
     * Moves the stream position forward by a given number of bytes.
     * This method is identical to <code>skipBytes(int)</code> except
     * that it allows for a larger skip distance.
     *
     * @param n a <code>long</code> containing the number of bytes to
     * be skipped.
     *
     * @return a <code>long</code> representing the number of bytes
     * skipped.
     *
     * @exception IOException if an I/O error occurs.
     */
    long skipBytes(long n) throws IOException;

    
Sets the current stream position to the desired location.  The
next read will occur at this location.  The bit offset is set
to 0.

 An IndexOutOfBoundsException will be thrown if
pos is smaller than the flushed position (as
returned by getflushedPosition).

 It is legal to seek past the end of the file; an
java.io.EOFException will be thrown only if a read is
performed.

Params:
  • pos – a long containing the desired file
pointer position.
Throws:
/**
     * Sets the current stream position to the desired location.  The
     * next read will occur at this location.  The bit offset is set
     * to 0.
     *
     * <p> An <code>IndexOutOfBoundsException</code> will be thrown if
     * <code>pos</code> is smaller than the flushed position (as
     * returned by <code>getflushedPosition</code>).
     *
     * <p> It is legal to seek past the end of the file; an
     * <code>java.io.EOFException</code> will be thrown only if a read is
     * performed.
     *
     * @param pos a <code>long</code> containing the desired file
     * pointer position.
     *
     * @exception IndexOutOfBoundsException if <code>pos</code> is smaller
     * than the flushed position.
     * @exception IOException if any other I/O error occurs.
     */
    void seek(long pos) throws IOException;

    
Marks a position in the stream to be returned to by a
subsequent call to reset.  Unlike a standard
InputStream, all ImageInputStreams
support marking.  Additionally, calls to mark and
reset may be nested arbitrarily.

 Unlike the mark methods declared by the
Reader and InputStream interfaces, no
readLimit parameter is used.  An arbitrary amount
of data may be read following the call to mark.

 The bit position used by the readBits method
is saved and restored by each pair of calls to
mark and reset.

 Note that it is valid for an ImageReader to call
flushBefore as part of a read operation.
Therefore, if an application calls mark prior to
passing that stream to an ImageReader, the application
should not assume that the marked position will remain valid after
the read operation has completed.

/**
     * Marks a position in the stream to be returned to by a
     * subsequent call to <code>reset</code>.  Unlike a standard
     * <code>InputStream</code>, all <code>ImageInputStream</code>s
     * support marking.  Additionally, calls to <code>mark</code> and
     * <code>reset</code> may be nested arbitrarily.
     *
     * <p> Unlike the <code>mark</code> methods declared by the
     * <code>Reader</code> and <code>InputStream</code> interfaces, no
     * <code>readLimit</code> parameter is used.  An arbitrary amount
     * of data may be read following the call to <code>mark</code>.
     *
     * <p> The bit position used by the <code>readBits</code> method
     * is saved and restored by each pair of calls to
     * <code>mark</code> and <code>reset</code>.
     *
     * <p> Note that it is valid for an <code>ImageReader</code> to call
     * <code>flushBefore</code> as part of a read operation.
     * Therefore, if an application calls <code>mark</code> prior to
     * passing that stream to an <code>ImageReader</code>, the application
     * should not assume that the marked position will remain valid after
     * the read operation has completed.
     */
    void mark();

    
Returns the stream pointer to its previous position, including
the bit offset, at the time of the most recent unmatched call
to mark.

 Calls to reset without a corresponding call
to mark have no effect.

 An IOException will be thrown if the previous
marked position lies in the discarded portion of the stream.

Throws:
  • IOException – if an I/O error occurs.
/**
     * Returns the stream pointer to its previous position, including
     * the bit offset, at the time of the most recent unmatched call
     * to <code>mark</code>.
     *
     * <p> Calls to <code>reset</code> without a corresponding call
     * to <code>mark</code> have no effect.
     *
     * <p> An <code>IOException</code> will be thrown if the previous
     * marked position lies in the discarded portion of the stream.
     *
     * @exception IOException if an I/O error occurs.
     */
    void reset() throws IOException;

    
Discards the initial portion of the stream prior to the
indicated position.  Attempting to seek to an offset within the
flushed portion of the stream will result in an
IndexOutOfBoundsException.

 Calling flushBefore may allow classes
implementing this interface to free up resources such as memory
or disk space that are being used to store data from the
stream.

Params:
  • pos – a long containing the length of the
stream prefix that may be flushed.
Throws:
/**
     * Discards the initial portion of the stream prior to the
     * indicated position.  Attempting to seek to an offset within the
     * flushed portion of the stream will result in an
     * <code>IndexOutOfBoundsException</code>.
     *
     * <p> Calling <code>flushBefore</code> may allow classes
     * implementing this interface to free up resources such as memory
     * or disk space that are being used to store data from the
     * stream.
     *
     * @param pos a <code>long</code> containing the length of the
     * stream prefix that may be flushed.
     *
     * @exception IndexOutOfBoundsException if <code>pos</code> lies
     * in the flushed portion of the stream or past the current stream
     * position.
     * @exception IOException if an I/O error occurs.
     */
    void flushBefore(long pos) throws IOException;

    
Discards the initial position of the stream prior to the current
stream position.  Equivalent to
flushBefore(getStreamPosition()).

Throws:
  • IOException – if an I/O error occurs.
/**
     * Discards the initial position of the stream prior to the current
     * stream position.  Equivalent to
     * <code>flushBefore(getStreamPosition())</code>.
     *
     * @exception IOException if an I/O error occurs.
     */
    void flush() throws IOException;

    
Returns the earliest position in the stream to which seeking
may be performed.  The returned value will be the maximum of
all values passed into previous calls to
flushBefore.

Returns:the earliest legal position for seeking, as a
long.
/**
     * Returns the earliest position in the stream to which seeking
     * may be performed.  The returned value will be the maximum of
     * all values passed into previous calls to
     * <code>flushBefore</code>.
     *
     * @return the earliest legal position for seeking, as a
     * <code>long</code>.
     */
    long getFlushedPosition();

    
Returns true if this ImageInputStream
caches data itself in order to allow seeking backwards.
Applications may consult this in order to decide how frequently,
or whether, to flush in order to conserve cache resources.

See Also:
Returns:true if this ImageInputStream
caches data.
/**
     * Returns <code>true</code> if this <code>ImageInputStream</code>
     * caches data itself in order to allow seeking backwards.
     * Applications may consult this in order to decide how frequently,
     * or whether, to flush in order to conserve cache resources.
     *
     * @return <code>true</code> if this <code>ImageInputStream</code>
     * caches data.
     *
     * @see #isCachedMemory
     * @see #isCachedFile
     */
    boolean isCached();

    
Returns true if this ImageInputStream
caches data itself in order to allow seeking backwards, and
the cache is kept in main memory.  Applications may consult
this in order to decide how frequently, or whether, to flush
in order to conserve cache resources.

See Also:
Returns:true if this ImageInputStream
caches data in main memory.
/**
     * Returns <code>true</code> if this <code>ImageInputStream</code>
     * caches data itself in order to allow seeking backwards, and
     * the cache is kept in main memory.  Applications may consult
     * this in order to decide how frequently, or whether, to flush
     * in order to conserve cache resources.
     *
     * @return <code>true</code> if this <code>ImageInputStream</code>
     * caches data in main memory.
     *
     * @see #isCached
     * @see #isCachedFile
     */
    boolean isCachedMemory();

    
Returns true if this ImageInputStream
caches data itself in order to allow seeking backwards, and
the cache is kept in a temporary file.  Applications may consult
this in order to decide how frequently, or whether, to flush
in order to conserve cache resources.

See Also:
Returns:true if this ImageInputStream
caches data in a temporary file.
/**
     * Returns <code>true</code> if this <code>ImageInputStream</code>
     * caches data itself in order to allow seeking backwards, and
     * the cache is kept in a temporary file.  Applications may consult
     * this in order to decide how frequently, or whether, to flush
     * in order to conserve cache resources.
     *
     * @return <code>true</code> if this <code>ImageInputStream</code>
     * caches data in a temporary file.
     *
     * @see #isCached
     * @see #isCachedMemory
     */
    boolean isCachedFile();

    
Closes the stream.  Attempts to access a stream that has been
closed may result in IOExceptions or incorrect
behavior.  Calling this method may allow classes implementing
this interface to release resources associated with the stream
such as memory, disk space, or file descriptors.

Throws:
  • IOException – if an I/O error occurs.
/**
     * Closes the stream.  Attempts to access a stream that has been
     * closed may result in <code>IOException</code>s or incorrect
     * behavior.  Calling this method may allow classes implementing
     * this interface to release resources associated with the stream
     * such as memory, disk space, or file descriptors.
     *
     * @exception IOException if an I/O error occurs.
     */
    void close() throws IOException;
}