- /*
- * @(#)ImageInputStream.java 1.44 03/01/23
- *
- * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
- * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
- */
-
- package javax.imageio.stream;
-
- import java.io.DataInput;
- import java.io.IOException;
- import java.nio.ByteOrder;
-
- /**
- * 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
- *
- * @version 0.5
- */
- public interface ImageInputStream extends DataInput {
-
- /**
- * 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
- * <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.
- *
- * <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 <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 <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 <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 <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 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
- * <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 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 <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 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 <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 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 <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 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 <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 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 <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 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 <code>0xffffffff</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 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 <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 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 <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 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 <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 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
- * <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 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>\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 <code>readUTF</code> is that
- * it reads a representation of a Unicode character string encoded
- * in Java 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& 0x1F) << 6) | (b & 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 & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 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>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.
- *
- * @return a UTF-encoded String from the stream.
- *
- * @exception EOFException if this stream reaches the end
- * before reading all the bytes.
- * @exception UTFDataFormatException if the bytes do not represent a
- * valid UTF-8 encoding of a string.
- * @exception IOException if an I/O error occurs.
- */
- String readUTF() throws IOException;
-
- /**
- * 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>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 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 <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>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 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 <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>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 withinb 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 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 <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>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 withinb 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 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 <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>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 withinb 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 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 <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>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 withinb 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 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 <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>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 withinb 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 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 <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>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 withinb 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 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.
- *
- * @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 <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
- * <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
- * <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 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
- * <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>
- * 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>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 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,
- * <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.
- *
- * @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 <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.
- *
- * <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>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 <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> <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>.
- */
- void mark();
-
- /**
- * Returns the file 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 postion. 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
- * file 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
- * <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
- * <code>flushBefore</code>.
- *
- * @return the earliest legal position for seeking, as a
- * <code>long</code>.
- */
- long getFlushedPosition();
-
- /**
- * 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 <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 <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 <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;
- }