PDFBOX-5660: optimize, as suggested by Valery Bokov; closes #425

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1932456 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/image/SampledImageReader.java

@@ -285,10 +285,14 @@ private static void readRasterFromAny(PDImage pdImage, WritableRaster raster)
                 final boolean isIndexed = colorSpace instanceof PDIndexed;
 
                 // calculate row padding
-                int padding = 0;
-                if (inputWidth * numComponents * bitsPerComponent % 8 > 0)
+                int padding = inputWidth * numComponents * bitsPerComponent % 8;
+                if (padding > 0)
                 {
-                    padding = 8 - (inputWidth * numComponents * bitsPerComponent % 8);
+                    padding = 8 - padding;
+                }
+                else
+                {
+                    padding = 0;
                 }
 
                 // read stream
@@ -498,7 +502,7 @@ private static BufferedImage from8bit(PDImage pdImage, WritableRaster raster, Re
             {
                 // we just need to copy all sample data, then convert to RGB image.
                 int inputResult = input.readNBytes(bank, 0, bank.length);
-                if (inputResult != (long) width * height * numComponents)
+                if (LOG.isDebugEnabled() && inputResult != (long) width * height * numComponents)
                 {
                     LOG.debug("Tried reading {} bytes but only {} bytes read",
                             (long) width * height * numComponents, inputResult);
@@ -616,10 +620,14 @@ private static BufferedImage fromAny(PDImage pdImage, WritableRaster raster, COS
                 }
 
                 // calculate row padding
-                int padding = 0;
-                if (inputWidth * numComponents * bitsPerComponent % 8 > 0)
+                int padding = inputWidth * numComponents * bitsPerComponent % 8;
+                if (padding > 0)
+                {
+                    padding = 8 - padding;
+                }
+                else
                 {
-                    padding = 8 - (inputWidth * numComponents * bitsPerComponent % 8);
+                    padding = 0;
                 }
 
                 // read stream