| /* |
| * 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, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package 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 |
| * {@code ImageReader}s. Various input sources, such as |
| * {@code InputStream}s and {@code File}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. |
| * |
| * <p> The enumeration class {@code java.nio.ByteOrder} is |
| * used to specify the byte order. A value of |
| * {@code 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 |
| * {@code ByteOrder.LITTLE_ENDIAN} order. |
| * |
| * <p> The byte order has no effect on the results returned from |
| * the {@code readBits} method (or the value written by |
| * {@code ImageOutputStream.writeBits}). |
| * |
| * @param byteOrder one of {@code ByteOrder.BIG_ENDIAN} or |
| * {@code java.nio.ByteOrder.LITTLE_ENDIAN}, 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} enumeration. |
| * |
| * @return one of {@code ByteOrder.BIG_ENDIAN} or |
| * {@code ByteOrder.LITTLE_ENDIAN}, 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} bytes from the stream, and |
| * stores them into {@code 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. |
| * |
| * <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} |
| * to indicate EOF. |
| * |
| * @exception NullPointerException if {@code b} is |
| * {@code null}. |
| * |
| * @exception IOException if an I/O error occurs. |
| */ |
| int read(byte[] b) throws IOException; |
| |
| /** |
| * Reads up to {@code len} bytes from the stream, and stores |
| * them into {@code b} starting at index {@code off}. |
| * The number of bytes read is returned. If no bytes can be read |
| * because the end of the stream has been reached, {@code -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. |
| * @param off the starting position within {@code b} to write to. |
| * @param len the maximum number of {@code byte}s to read. |
| * |
| * @return the number of bytes actually read, or {@code -1} |
| * to indicate EOF. |
| * |
| * @exception NullPointerException if {@code b} is |
| * {@code null}. |
| * @exception IndexOutOfBoundsException if {@code off} is |
| * negative, {@code len} is negative, or {@code off + len} |
| * is greater than {@code b.length}. |
| * @exception IOException if an I/O error occurs. |
| */ |
| int read(byte[] b, int off, int len) throws IOException; |
| |
| /** |
| * Reads up to {@code len} bytes from the stream, and |
| * modifies the supplied {@code 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 |
| * {@code IIOByteBuffer}. |
| * |
| * <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}s to read. |
| * |
| * @exception IndexOutOfBoundsException if {@code len} is |
| * negative. |
| * @exception NullPointerException if {@code buf} is |
| * {@code null}. |
| * |
| * @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} |
| * value of {@code true} if it is nonzero, {@code false} |
| * 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 |
| * {@code byte} value. Byte values between {@code 0x00} |
| * and {@code 0x7f} represent integer values between |
| * {@code 0} and {@code 127}. Values between |
| * {@code 0x80} and {@code 0xff} represent negative |
| * values from {@code -128} to {@code /1}. |
| * |
| * <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 {@code 0xff} in order to strip off |
| * any sign-extension bits, and returns it as a {@code byte} |
| * value. |
| * |
| * <p> Thus, byte values between {@code 0x00} and |
| * {@code 0x7f} are simply returned as integer values between |
| * {@code 0} and {@code 127}. Values between |
| * {@code 0x80} and {@code 0xff}, which normally |
| * represent negative {@code byte} values, will be mapped into |
| * positive integers between {@code 128} and |
| * {@code 255}. |
| * |
| * <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 {@code short} 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 {@code int}, masks it with |
| * {@code 0xffff} in order to strip off any sign-extension |
| * buts, and returns the result as an unsigned {@code int} |
| * 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 {@code readUnsignedShort}, except that the |
| * result is returned using the {@code char} 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 {@code int}. |
| * |
| * <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 {@code 0xffffffffL} in order to |
| * strip off any sign-extension bits, and returns the result as an |
| * unsigned {@code long} 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 {@code long}. |
| * |
| * <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 {@code float}. |
| * |
| * <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 {@code double}. |
| * |
| * <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 |
| * {@code String}. Note that because this method processes |
| * bytes, it does not support input of the full Unicode character |
| * set. |
| * |
| * <p> If end of file is encountered before even one byte can be |
| * read, then {@code null} is returned. Otherwise, each byte |
| * that is read is converted to type {@code char} by |
| * zero-extension. If the character {@code '\n'} is |
| * encountered, it is discarded and reading ceases. If the |
| * character {@code '\r'} is encountered, it is discarded |
| * and, if the following byte converts  to the character |
| * {@code '\n'}, then that is discarded also; reading then |
| * ceases. If end of file is encountered before either of the |
| * characters {@code '\n'} and {@code '\r'} is |
| * encountered, reading ceases. Once reading has ceased, a |
| * {@code String} is returned that contains all the |
| * characters read and not discarded, taken in order. Note that |
| * every character in this string will have a value less than |
| * <code>\u0100</code>, that is, {@code (char)256}. |
| * |
| * <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 |
| * <a href="../../../java/io/DataInput.html#modified-utf-8">modified |
| * UTF-8</a> |
| * format. The general contract of {@code readUTF} is that |
| * it reads a representation of a Unicode character string encoded |
| * in modified UTF-8 format; this string of characters is |
| * then returned as a {@code String}. |
| * |
| * <p> First, two bytes are read and used to construct an unsigned |
| * 16-bit integer in the manner of the |
| * {@code readUnsignedShort} 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} (where {@code x} means "may be |
| * {@code 0} or {@code 1}"), then the group consists of |
| * just that byte. The byte is zero-extended to form a character. |
| * |
| * <p> If the first byte of a group matches the bit pattern |
| * {@code 110xxxxx}, then the group consists of that byte |
| * {@code a} and a second byte {@code b}. If there is no |
| * byte {@code b} (because byte {@code a} was the last |
| * of the bytes to be read), or if byte {@code b} does not |
| * match the bit pattern {@code 10xxxxxx}, then a |
| * {@code UTFDataFormatException} is thrown. Otherwise, the |
| * group is converted to the character: |
| * |
| * <pre><code> |
| * (char)(((a& 0x1F) << 6) | (b & 0x3F)) |
| * </code></pre> |
| * |
| * If the first byte of a group matches the bit pattern |
| * {@code 1110xxxx}, then the group consists of that byte |
| * {@code a} and two more bytes {@code b} and |
| * {@code c}. If there is no byte {@code c} (because |
| * byte {@code a} was one of the last two of the bytes to be |
| * read), or either byte {@code b} or byte {@code c} |
| * does not match the bit pattern {@code 10xxxxxx}, then a |
| * {@code UTFDataFormatException} is thrown. Otherwise, the |
| * group is converted to the character: |
| * |
| * <pre><code> |
| * (char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F)) |
| * </code></pre> |
| * |
| * If the first byte of a group matches the pattern |
| * {@code 1111xxxx} or the pattern {@code 10xxxxxx}, |
| * then a {@code UTFDataFormatException} is thrown. |
| * |
| * <p> If end of file is encountered at any time during this |
| * entire process, then an {@code java.io.EOFException} is thrown. |
| * |
| * <p> After every group has been converted to a character by this |
| * process, the characters are gathered, in the same order in |
| * which their corresponding groups were read from the input |
| * stream, to form a {@code String}, which is returned. |
| * |
| * <p> The 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 {@code len} bytes from the stream, and stores them |
| * into {@code b} starting at index {@code off}. |
| * If the end of the stream is reached, an {@code java.io.EOFException} |
| * 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} to write to. |
| * @param len the maximum number of {@code byte}s to read. |
| * |
| * @exception IndexOutOfBoundsException if {@code off} is |
| * negative, {@code len} is negative, or {@code off + len} |
| * is greater than {@code b.length}. |
| * @exception NullPointerException if {@code b} is |
| * {@code null}. |
| * @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 {@code b.length} bytes from the stream, and stores them |
| * into {@code b} starting at index {@code 0}. |
| * If the end of the stream is reached, an {@code java.io.EOFException} |
| * 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}s. |
| * |
| * @exception NullPointerException if {@code b} is |
| * {@code null}. |
| * @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 {@code len} shorts (signed 16-bit integers) from the |
| * stream according to the current byte order, and |
| * stores them into {@code s} starting at index |
| * {@code off}. If the end of the stream is reached, an |
| * {@code java.io.EOFException} 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} to write to. |
| * @param len the maximum number of {@code short}s to read. |
| * |
| * @exception IndexOutOfBoundsException if {@code off} is |
| * negative, {@code len} is negative, or {@code off + len} |
| * is greater than {@code s.length}. |
| * @exception NullPointerException if {@code s} is |
| * {@code null}. |
| * @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 {@code len} chars (unsigned 16-bit integers) from the |
| * stream according to the current byte order, and |
| * stores them into {@code c} starting at index |
| * {@code off}. If the end of the stream is reached, an |
| * {@code java.io.EOFException} 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} to write to. |
| * @param len the maximum number of {@code char}s to read. |
| * |
| * @exception IndexOutOfBoundsException if {@code off} is |
| * negative, {@code len} is negative, or {@code off + len} |
| * is greater than {@code c.length}. |
| * @exception NullPointerException if {@code c} is |
| * {@code null}. |
| * @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 {@code len} ints (signed 32-bit integers) from the |
| * stream according to the current byte order, and |
| * stores them into {@code i} starting at index |
| * {@code off}. If the end of the stream is reached, an |
| * {@code java.io.EOFException} 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} to write to. |
| * @param len the maximum number of {@code int}s to read. |
| * |
| * @exception IndexOutOfBoundsException if {@code off} is |
| * negative, {@code len} is negative, or {@code off + len} |
| * is greater than {@code i.length}. |
| * @exception NullPointerException if {@code i} is |
| * {@code null}. |
| * @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 {@code len} longs (signed 64-bit integers) from the |
| * stream according to the current byte order, and |
| * stores them into {@code l} starting at index |
| * {@code off}. If the end of the stream is reached, an |
| * {@code java.io.EOFException} 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} to write to. |
| * @param len the maximum number of {@code long}s to read. |
| * |
| * @exception IndexOutOfBoundsException if {@code off} is |
| * negative, {@code len} is negative, or {@code off + len} |
| * is greater than {@code l.length}. |
| * @exception NullPointerException if {@code l} is |
| * {@code null}. |
| * @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 {@code len} floats (32-bit IEEE single-precision |
| * floats) from the stream according to the current byte order, |
| * and stores them into {@code f} starting at |
| * index {@code off}. If the end of the stream is reached, |
| * an {@code java.io.EOFException} 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} to write to. |
| * @param len the maximum number of {@code float}s to read. |
| * |
| * @exception IndexOutOfBoundsException if {@code off} is |
| * negative, {@code len} is negative, or {@code off + len} |
| * is greater than {@code f.length}. |
| * @exception NullPointerException if {@code f} is |
| * {@code null}. |
| * @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 {@code len} doubles (64-bit IEEE double-precision |
| * floats) from the stream according to the current byte order, |
| * and stores them into {@code d} starting at |
| * index {@code off}. If the end of the stream is reached, |
| * an {@code java.io.EOFException} 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} to write to. |
| * @param len the maximum number of {@code double}s to read. |
| * |
| * @exception IndexOutOfBoundsException if {@code off} is |
| * negative, {@code len} is negative, or {@code off + len} |
| * is greater than {@code d.length}. |
| * @exception NullPointerException if {@code d} is |
| * {@code null}. |
| * @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. |
| * |
| * @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} 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 skipBytes}, or any {@code read} or |
| * {@code readFully} method. |
| * |
| * @return an {@code int} 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}, 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} |
| * between 0 and 7, inclusive. |
| * |
| * @exception IllegalArgumentException if {@code bitOffset} |
| * 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} with the value {@code 0} or |
| * {@code 1}. The bit offset is advanced by one and reduced |
| * modulo 8. |
| * |
| * @return an {@code int} containing the value {@code 0} |
| * or {@code 1}. |
| * |
| * @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 |
| * {@code long}, with the first bit read becoming the most |
| * significant bit of the output. The read starts within the byte |
| * indicated by {@code getStreamPosition}, at the bit given |
| * by {@code getBitOffset}. The bit offset is advanced by |
| * {@code numBits} 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)} may thus not |
| * be equal to that of {@code readInt()} if a reverse network |
| * byte order is being used (i.e., {@code getByteOrder() == false}). |
| * |
| * <p> If the end of the stream is encountered before all the bits |
| * have been read, an {@code java.io.EOFException} is thrown. |
| * |
| * @param numBits the number of bits to read, as an {@code int} |
| * between 0 and 64, inclusive. |
| * @return the bitstring, as a {@code long} with the last bit |
| * read stored in the least significant bit. |
| * |
| * @exception IllegalArgumentException if {@code numBits} |
| * 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, |
| * {@code -1} is returned. |
| * |
| * @return a {@code long} containing the length of the |
| * stream, if known, or else {@code -1}. |
| * |
| * @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} containing the number of bytes to |
| * be skipped. |
| * |
| * @return an {@code int} 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)} except |
| * that it allows for a larger skip distance. |
| * |
| * @param n a {@code long} containing the number of bytes to |
| * be skipped. |
| * |
| * @return a {@code long} 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} will be thrown if |
| * {@code pos} is smaller than the flushed position (as |
| * returned by {@code getflushedPosition}). |
| * |
| * <p> It is legal to seek past the end of the file; an |
| * {@code java.io.EOFException} will be thrown only if a read is |
| * performed. |
| * |
| * @param pos a {@code long} containing the desired file |
| * pointer position. |
| * |
| * @exception IndexOutOfBoundsException if {@code pos} 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}. Unlike a standard |
| * {@code InputStream}, all {@code ImageInputStream}s |
| * support marking. Additionally, calls to {@code mark} and |
| * {@code reset} may be nested arbitrarily. |
| * |
| * <p> Unlike the {@code mark} methods declared by the |
| * {@code Reader} and {@code InputStream} interfaces, no |
| * {@code readLimit} parameter is used. An arbitrary amount |
| * of data may be read following the call to {@code mark}. |
| * |
| * <p> The bit position used by the {@code readBits} method |
| * is saved and restored by each pair of calls to |
| * {@code mark} and {@code reset}. |
| * |
| * <p> Note that it is valid for an {@code ImageReader} to call |
| * {@code flushBefore} as part of a read operation. |
| * Therefore, if an application calls {@code mark} prior to |
| * passing that stream to an {@code ImageReader}, 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 {@code mark}. |
| * |
| * <p> Calls to {@code reset} without a corresponding call |
| * to {@code mark} have no effect. |
| * |
| * <p> An {@code IOException} 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 |
| * {@code IndexOutOfBoundsException}. |
| * |
| * <p> Calling {@code 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. |
| * |
| * @param pos a {@code long} containing the length of the |
| * stream prefix that may be flushed. |
| * |
| * @exception IndexOutOfBoundsException if {@code pos} 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())}. |
| * |
| * @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}. |
| * |
| * @return the earliest legal position for seeking, as a |
| * {@code long}. |
| */ |
| long getFlushedPosition(); |
| |
| /** |
| * Returns {@code true} if this {@code 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. |
| * |
| * @return {@code true} if this {@code ImageInputStream} |
| * caches data. |
| * |
| * @see #isCachedMemory |
| * @see #isCachedFile |
| */ |
| boolean isCached(); |
| |
| /** |
| * Returns {@code true} if this {@code 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. |
| * |
| * @return {@code true} if this {@code ImageInputStream} |
| * caches data in main memory. |
| * |
| * @see #isCached |
| * @see #isCachedFile |
| */ |
| boolean isCachedMemory(); |
| |
| /** |
| * Returns {@code true} if this {@code 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. |
| * |
| * @return {@code true} if this {@code ImageInputStream} |
| * 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}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; |
| } |
