ImageReader implementing class for JPEG images

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@193631 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 161 insertions, 0 deletions

diff --git a/src/org/apache/fop/image/analyser/JPEGReader.java b/src/org/apache/fop/image/analyser/JPEGReader.java
new file mode 100644
index 000000000..e7370ae4e
--- /dev/null
+++ b/src/org/apache/fop/image/analyser/JPEGReader.java
@@ -0,0 +1,161 @@
+/*
+ ============================================================================
+                   The Apache Software License, Version 1.1
+ ============================================================================
+    Copyright (C) 1999 The Apache Software Foundation. All rights reserved.
+ Redistribution and use in source and binary forms, with or without modifica-
+ tion, are permitted provided that the following conditions are met:
+ 1. Redistributions of  source code must  retain the above copyright  notice,
+    this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright notice,
+    this list of conditions and the following disclaimer in the documentation
+    and/or other materials provided with the distribution.
+ 3. The end-user documentation included with the redistribution, if any, must
+    include  the following  acknowledgment:  "This product includes  software
+    developed  by the  Apache Software Foundation  (http://www.apache.org/)."
+    Alternately, this  acknowledgment may  appear in the software itself,  if
+    and wherever such third-party acknowledgments normally appear.
+ 4. The names "Fop" and  "Apache Software Foundation"  must not be used to
+    endorse  or promote  products derived  from this  software without  prior
+    written permission. For written permission, please contact
+    apache@apache.org.
+ 5. Products  derived from this software may not  be called "Apache", nor may
+    "Apache" appear  in their name,  without prior written permission  of the
+    Apache Software Foundation.
+ THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
+ INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ FITNESS  FOR A PARTICULAR  PURPOSE ARE  DISCLAIMED.  IN NO  EVENT SHALL  THE
+ APACHE SOFTWARE  FOUNDATION  OR ITS CONTRIBUTORS  BE LIABLE FOR  ANY DIRECT,
+ INDIRECT, INCIDENTAL, SPECIAL,  EXEMPLARY, OR CONSEQUENTIAL  DAMAGES (INCLU-
+ DING, BUT NOT LIMITED TO, PROCUREMENT  OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ OF USE, DATA, OR  PROFITS; OR BUSINESS  INTERRUPTION)  HOWEVER CAUSED AND ON
+ ANY  THEORY OF LIABILITY,  WHETHER  IN CONTRACT,  STRICT LIABILITY,  OR TORT
+ (INCLUDING  NEGLIGENCE OR  OTHERWISE) ARISING IN  ANY WAY OUT OF THE  USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ This software  consists of voluntary contributions made  by many individuals
+ on  behalf of the Apache Software  Foundation and was  originally created by
+ James Tauber <jtauber@jtauber.com>. For more  information on the Apache
+ Software Foundation, please see <http://www.apache.org/>.
+ */
+
+package org.apache.fop.image.analyser;
+
+// Java
+import java.io.BufferedInputStream;
+import java.io.IOException;
+
+/**
+ * ImageReader object for JPEG image type.
+ * @author Pankaj Narula
+ * @version 1.0
+ */
+public class JPEGReader extends AbstractImageReader {
+  /**
+   * Only SOFn and APPn markers are defined as SOFn is needed for the height and
+   * width search. APPn is also defined because if the JPEG contains thumbnails
+   * the dimensions of the thumnail would also be after the SOFn marker enclosed
+   * inside the APPn marker. And we don't want to confuse those dimensions with
+   * the image dimensions.
+   */
+  static protected final int MARK = 0xff; //Beginneing of a Marker
+  static protected final int NULL = 0x00; //Special case for 0xff00
+  static protected final int SOF1 = 0xc0; //Baseline DCT
+  static protected final int SOF2 = 0xc1; //Extended Sequential DCT
+  static protected final int SOF3 = 0xc2; //Progrssive DCT only PDF 1.3
+  static protected final int SOFA = 0xca; //Progressice DCT only PDF 1.3
+  static protected final int APP0 = 0xe0; //Application marker, JFIF
+  static protected final int APPF = 0xef; //Application marker
+  static protected final int SOS = 0xda; //Start of Scan
+  static protected final int SOI = 0xd8; //start of Image
+  static protected final int JPG_SIG_LENGTH = 2;
+
+  protected byte[] header;
+
+  public boolean verifySignature(BufferedInputStream fis)
+  throws IOException {
+    this.imageStream = fis;
+    this.setDefaultHeader();
+    boolean supported = ((header[0] == (byte) 0xff) &&
+                         (header[1] == (byte) 0xd8));
+    if (supported) {
+      setDimension();
+      return true;
+    } else
+      return false;
+  }
+
+  public String getMimeType() {
+    return "image/jpeg";
+  }
+
+  protected void setDefaultHeader() throws IOException {
+    this.header = new byte[JPG_SIG_LENGTH];
+    try {
+      this.imageStream.mark(JPG_SIG_LENGTH + 1);
+      this.imageStream.read(header);
+      this.imageStream.reset();
+    } catch (IOException ex) {
+      try {
+        this.imageStream.reset();
+      } catch (IOException exbis) {}
+      throw ex;
+    }
+  }
+
+  protected void setDimension() throws IOException {
+    try {
+      int marker = NULL;
+      long length, skipped;
+      outer:
+      while (imageStream.available() > 0) {
+        while ((marker = imageStream.read()) != MARK) {
+          ;
+        }
+        do {
+          marker = imageStream.read();
+        } while (marker == MARK)
+          ;
+        switch (marker) {
+          case SOI :
+            break;
+          case NULL:
+            break;
+          case SOF1:
+          case SOF2:
+          case SOF3: //SOF3 and SOFA are only supported by PDF 1.3
+          case SOFA:
+            this.skip(3);
+            this.height = this.read2bytes();
+            this.width = this.read2bytes();
+            break outer;
+          default:
+            length = this.read2bytes();
+            skipped = this.skip(length - 2);
+            if (skipped != length - 2)
+              throw new IOException("Skipping Error");
+        }
+      }
+    } catch (IOException ioe) {
+      try {
+        this.imageStream.reset();
+      } catch (IOException exbis) {}
+      throw ioe;
+    }
+  }
+
+  protected int read2bytes() throws IOException {
+    int byte1 = imageStream.read();
+    int byte2 = imageStream.read();
+    return (int)((byte1 << 8) | byte2);
+  }
+
+  protected long skip(long n) throws IOException {
+    long discarded = 0;
+    while (discarded != n) {
+      imageStream.read();
+      discarded++;
+    }
+    return discarded; //scope for exception
+  }
+}
+