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package com.sun.imageio.plugins.jpeg;

import javax.imageio.metadata.IIOInvalidTreeException;
import javax.imageio.metadata.IIOMetadataNode;
import javax.imageio.stream.ImageOutputStream;

import java.io.IOException;

import org.w3c.dom.Node;
import org.w3c.dom.NamedNodeMap;

All metadata is stored in MarkerSegments. Marker segments that we know about are stored in subclasses of this basic class, which used for unrecognized APPn marker segments. XXX break out UnknownMarkerSegment as a subclass and make this abstract, avoiding unused data field.
/** * All metadata is stored in MarkerSegments. Marker segments * that we know about are stored in subclasses of this * basic class, which used for unrecognized APPn marker * segments. XXX break out UnknownMarkerSegment as a subclass * and make this abstract, avoiding unused data field. */
class MarkerSegment implements Cloneable { protected static final int LENGTH_SIZE = 2; // length is 2 bytes int tag; // See JPEG.java int length; /* Sometimes needed by subclasses; doesn't include itself. Meaningful only if constructed from a stream */ byte [] data = null; // Raw segment data, used for unrecognized segments boolean unknown = false; // Set to true if the tag is not recognized
Constructor for creating MarkerSegments by reading from an ImageInputStream.
/** * Constructor for creating <code>MarkerSegment</code>s by reading * from an <code>ImageInputStream</code>. */
MarkerSegment(JPEGBuffer buffer) throws IOException { buffer.loadBuf(3); // tag plus length tag = buffer.buf[buffer.bufPtr++] & 0xff; length = (buffer.buf[buffer.bufPtr++] & 0xff) << 8; length |= buffer.buf[buffer.bufPtr++] & 0xff; length -= 2; // JPEG length includes itself, we don't buffer.bufAvail -= 3; // Now that we know the true length, ensure that we've got it, // or at least a bufferful if length is too big. buffer.loadBuf(length); }
Constructor used when creating segments other than by reading them from a stream.
/** * Constructor used when creating segments other than by * reading them from a stream. */
MarkerSegment(int tag) { this.tag = tag; length = 0; }
Construct a MarkerSegment from an "unknown" DOM Node.
/** * Construct a MarkerSegment from an "unknown" DOM Node. */
MarkerSegment(Node node) throws IIOInvalidTreeException { // The type of node should have been verified already. // get the attribute and assign it to the tag tag = getAttributeValue(node, null, "MarkerTag", 0, 255, true); length = 0; // get the user object and clone it to the data if (node instanceof IIOMetadataNode) { IIOMetadataNode iioNode = (IIOMetadataNode) node; try { data = (byte []) iioNode.getUserObject(); } catch (Exception e) { IIOInvalidTreeException newGuy = new IIOInvalidTreeException ("Can't get User Object", node); newGuy.initCause(e); throw newGuy; } } else { throw new IIOInvalidTreeException ("Node must have User Object", node); } }
Deep copy of data array.
/** * Deep copy of data array. */
protected Object clone() { MarkerSegment newGuy = null; try { newGuy = (MarkerSegment) super.clone(); } catch (CloneNotSupportedException e) {} // won't happen if (this.data != null) { newGuy.data = (byte[]) data.clone(); } return newGuy; }
We have determined that we don't know the type, so load the data using the length parameter.
/** * We have determined that we don't know the type, so load * the data using the length parameter. */
void loadData(JPEGBuffer buffer) throws IOException { data = new byte[length]; buffer.readData(data); } IIOMetadataNode getNativeNode() { IIOMetadataNode node = new IIOMetadataNode("unknown"); node.setAttribute("MarkerTag", Integer.toString(tag)); node.setUserObject(data); return node; } static int getAttributeValue(Node node, NamedNodeMap attrs, String name, int min, int max, boolean required) throws IIOInvalidTreeException { if (attrs == null) { attrs = node.getAttributes(); } String valueString = attrs.getNamedItem(name).getNodeValue(); int value = -1; if (valueString == null) { if (required) { throw new IIOInvalidTreeException (name + " attribute not found", node); } } else { value = Integer.parseInt(valueString); if ((value < min) || (value > max)) { throw new IIOInvalidTreeException (name + " attribute out of range", node); } } return value; }
Writes the marker, tag, and length. Note that length should be verified by the caller as a correct JPEG length, i.e it includes itself.
/** * Writes the marker, tag, and length. Note that length * should be verified by the caller as a correct JPEG * length, i.e it includes itself. */
void writeTag(ImageOutputStream ios) throws IOException { ios.write(0xff); ios.write(tag); write2bytes(ios, length); }
Writes the data for this segment to the stream in valid JPEG format.
/** * Writes the data for this segment to the stream in * valid JPEG format. */
void write(ImageOutputStream ios) throws IOException { length = 2 + ((data != null) ? data.length : 0); writeTag(ios); if (data != null) { ios.write(data); } } static void write2bytes(ImageOutputStream ios, int value) throws IOException { ios.write((value >> 8) & 0xff); ios.write(value & 0xff); } void printTag(String prefix) { System.out.println(prefix + " marker segment - marker = 0x" + Integer.toHexString(tag)); System.out.println("length: " + length); } void print() { printTag("Unknown"); if (length > 10) { System.out.print("First 5 bytes:"); for (int i=0;i<5;i++) { System.out.print(" Ox" + Integer.toHexString((int)data[i])); } System.out.print("\nLast 5 bytes:"); for (int i=data.length-5;i<data.length;i++) { System.out.print(" Ox" + Integer.toHexString((int)data[i])); } } else { System.out.print("Data:"); for (int i=0;i<data.length;i++) { System.out.print(" Ox" + Integer.toHexString((int)data[i])); } } System.out.println(); } }