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Diffstat (limited to 'gcc-4.4.3/libjava/classpath/gnu/javax/imageio/jpeg/JPEGImageInputStream.java')
| -rw-r--r-- | gcc-4.4.3/libjava/classpath/gnu/javax/imageio/jpeg/JPEGImageInputStream.java | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/gcc-4.4.3/libjava/classpath/gnu/javax/imageio/jpeg/JPEGImageInputStream.java b/gcc-4.4.3/libjava/classpath/gnu/javax/imageio/jpeg/JPEGImageInputStream.java new file mode 100644 index 000000000..29a12f346 --- /dev/null +++ b/gcc-4.4.3/libjava/classpath/gnu/javax/imageio/jpeg/JPEGImageInputStream.java @@ -0,0 +1,188 @@ +/* JPEGImageInputStream.java -- + Copyright (C) 2006 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package gnu.javax.imageio.jpeg; + +import java.io.IOException; +import javax.imageio.stream.ImageInputStream; +import javax.imageio.stream.ImageInputStreamImpl; + +public class JPEGImageInputStream + extends ImageInputStreamImpl +{ + private ImageInputStream in; + + byte marker; + + public JPEGImageInputStream(ImageInputStream in) + { + super(); + + this.in = in; + } + + public int read() + throws IOException + { + setBitOffset(0); + return in.read(); + } + + public int read(byte[] data, int offset, int len) + throws IOException + { + setBitOffset(0); + return in.read(data, offset, len); + } + + /** + * Pull a byte from the stream, this checks to see if the byte is 0xff + * and if the next byte isn't 0x00 (stuffed byte) it errors out. If it's + * 0x00 then it simply ignores the byte. + * + * @return the next byte in the buffer + * + * @throws IOException TODO + * @throws BitStreamException TODO + */ + private byte pullByte() throws IOException, JPEGMarkerFoundException + { + byte mybyte = readByte(); + // FIXME: handle multiple 0xff in a row + if(mybyte==(byte)(0xff)) + { + byte secondbyte = readByte(); + if(secondbyte != (byte)(0x00)) + { + marker = secondbyte; + throw new JPEGMarkerFoundException(); + } + } + return mybyte; + } + + /** + * This returns the marker that was last encountered. This should only be + * used if removeBit() throws a MarkerTagFound exception. + * + * @return marker as byte + */ + public byte getMarker() + { + return marker; + } + + /** + * Removes a bit from the buffer. (Removes from the top of a queue). This + * also checks for markers and throws MarkerTagFound exception if it does. + * If MarkerTagFound is thrown you can use getMarker() method to get the + * marker that caused the throw. + * + * @param l specifies how many bits you want to remove and add to the + * integer + * @return the amount of bits specified by l as an integer + * + * @throws IOException TODO + * @throws JPEGMarkerFoundException + * @throws BitStreamException TODO + */ + public int readBit() + throws IOException, JPEGMarkerFoundException +{ + checkClosed(); + + // Calc new bit offset here, readByte resets it. + int newOffset = (bitOffset + 1) & 0x7; + + byte data = pullByte(); + + if (bitOffset != 0) + { + seek(getStreamPosition() - 1); + data = (byte) (data >> (8 - newOffset)); + } + + bitOffset = newOffset; + return data & 0x1; +} + + + /** + * This method skips over the the data and finds the next position + * in the bit sequence with a X'FF' X'??' sequence. Multiple X'FF + * bytes in sequence are considered padding and interpreted as one + * X'FF byte. + * + * @return the next marker byte in the stream + * @throws IOException if the end of the stream is reached + * unexpectedly + */ + public byte findNextMarker() + throws IOException + { + boolean marked0xff = false; + byte byteinfo = JPEGMarker.X00; + + setBitOffset(0); + while (true) + { + byteinfo = readByte(); + if (!marked0xff) + { + if (byteinfo == JPEGMarker.XFF) + marked0xff = true; + } + else + { + if (byteinfo == JPEGMarker.XFF) + // Ignore the value 0xff when it is immediately + // followed by another 0xff byte. + continue; + else if (byteinfo == JPEGMarker.X00) + // The sequence 0xff 0x00 is used to encode the + // actual value 0xff. So restart our search for a + // marker. + marked0xff = false; + else + // One or more 0xff values were follwed by a + // non-0x00, non-0xff value so return this as the + // marker byte. + return byteinfo; + } + } + } +} |