1 files changed, 86 insertions, 0 deletions
diff --git a/src/main/java/org/pdfbox/pdmodel/graphics/predictor/Sub.java b/src/main/java/org/pdfbox/pdmodel/graphics/predictor/Sub.java
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+++ b/src/main/java/org/pdfbox/pdmodel/graphics/predictor/Sub.java
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+/**
+ * Copyright (c) 2005, www.pdfbox.org
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, 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. Neither the name of pdfbox; nor the names of its
+ *    contributors may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS 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 REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, 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.
+ *
+ * http://www.pdfbox.org
+ *
+ */
+package org.pdfbox.pdmodel.graphics.predictor;
+
+/**
+ * The sub algorithm.
+ * 
+ * <code>Sub(i,j) = Raw(i,j) - Raw(i-1,j)</code>
+ * 
+ * <code>Raw(i,j) = Sub(i,j) + Raw(i-1,j)</code>
+ * 
+ * @author xylifyx@yahoo.co.uk
+ * @version $Revision: 1.2 $
+ */
+public class Sub extends PredictorAlgorithm 
+{
+    /**
+     * @see org.pdfbox.pdmodel.graphics.predictor.PredictorAlgorithm#encodeLine(byte[], byte[], int, int, int, int)
+     */
+    public void encodeLine(byte[] src, byte[] dest, int srcDy, int srcOffset,
+            int destDy, int destOffset) 
+    {
+        int bpl = getWidth()*getBpp();
+        int bpp = getBpp();
+        // case: x < bpp
+        for (int x = 0; x < bpl && x < bpp; x++) 
+        {
+            dest[x + destOffset] = src[x + srcOffset];
+        }
+        // otherwise
+        for (int x = getBpp(); x < bpl; x++) 
+        {
+            dest[x + destOffset] = (byte) (src[x + srcOffset] - src[x
+                    + srcOffset - bpp]);
+        }
+    }
+
+    /**
+     * @see org.pdfbox.pdmodel.graphics.predictor.PredictorAlgorithm#decodeLine(byte[], byte[], int, int, int, int)
+     */
+    public void decodeLine(byte[] src, byte[] dest, int srcDy, int srcOffset,
+            int destDy, int destOffset) 
+    {
+        int bpl = getWidth()*getBpp();
+        int bpp = getBpp();
+        // case: x < bpp
+        for (int x = 0; x < bpl && x < bpp; x++) 
+        {
+            dest[x + destOffset] = src[x + srcOffset];
+        }
+        // otherwise
+        for (int x = getBpp(); x < bpl; x++) 
+        {
+            dest[x + destOffset] = (byte) (src[x + srcOffset] + dest[x
+                    + destOffset - bpp]);
+        }
+    }
+}