GH-79 migrated to slice over buffer get operations.

core/core-awt/src/main/java/org/icepdf/core/pobjects/Stream.java

@@ -161,10 +161,7 @@ public ByteBuffer getDecodedStreamByteBuffer() {
 
     public ByteBuffer getDecodedStreamByteBuffer(int presiz) {
         byte[] decodeBytes = getDecodedStreamBytes(presiz);
-        ByteBuffer decodedByteBuffer = ByteBuffer.allocateDirect(decodeBytes.length);
-        decodedByteBuffer.put(decodeBytes);
-        decodedByteBuffer.position(0);
-        return decodedByteBuffer;
+        return ByteBuffer.wrap(decodeBytes);
     }
 
     /**

core/core-awt/src/main/java/org/icepdf/core/pobjects/structure/Header.java

@@ -21,11 +21,10 @@ public class Header {
     private double version;
 
     public ByteBuffer parseHeader(ByteBuffer byteBuffer) {
-        ByteBuffer headerBuffer = ByteBuffer.allocateDirect(Math.min(byteBuffer.limit(), 8 * 1024));
-        while (headerBuffer.hasRemaining()) {
-            headerBuffer.put(byteBuffer.get());
-        }
-        headerBuffer.flip();
+        byteBuffer.limit(Math.min(byteBuffer.limit(), 8 * 1024));
+        ByteBuffer headerBuffer = byteBuffer.slice();
+        byteBuffer.limit(byteBuffer.capacity());
+
         int matchPosition = 0;
         int matchLength = PDF_VERSION_MARKER.length - 1;
         while (headerBuffer.hasRemaining()) {

core/core-awt/src/main/java/org/icepdf/core/pobjects/structure/Trailer.java

@@ -56,12 +56,11 @@ public void parseXrefOffset(ByteBuffer byteBuffer) throws CrossReferenceStateExc
 
     private void parseXrefOffset(ByteBuffer byteBuffer, int bufferSize) throws CrossReferenceStateException {
         // find xref offset.
-        ByteBuffer footerBuffer = ByteBuffer.allocateDirect(bufferSize);
-        byteBuffer.position(byteBuffer.limit() - footerBuffer.limit());
-        while (footerBuffer.hasRemaining()) {
-            footerBuffer.put(byteBuffer.get());
-        }
-        footerBuffer.flip();
+        byteBuffer.position(byteBuffer.limit() - bufferSize);
+        byteBuffer.limit(byteBuffer.capacity());
+        ByteBuffer footerBuffer = byteBuffer.slice();
+        byteBuffer.limit(byteBuffer.capacity());
+
         // find end of file marker and startxref so we can parse the xref offset.
         int offsetEnd = ByteBufferUtil.findReverseString(footerBuffer, footerBuffer.limit(), PDF_EOF_MARKER);
         if (offsetEnd == footerBuffer.limit()) {

core/core-awt/src/main/java/org/icepdf/core/util/ByteBufferUtil.java

@@ -10,15 +10,15 @@
  */
 public class ByteBufferUtil {
 
-    public static ByteBuffer copyObjectStreamSlice(ByteBuffer objectByteBuffer, int objectOffsetStart, int objectOffsetEnd) {
+    public static ByteBuffer sliceObjectStream(ByteBuffer objectByteBuffer, int objectOffsetStart, int objectOffsetEnd) {
         int streamLength = objectOffsetEnd - objectOffsetStart;
         int oldLimit = objectByteBuffer.limit();
-        ByteBuffer streamByteBuffer = ByteBuffer.allocateDirect(streamLength);
+        int boundLimit = Math.min(objectOffsetStart + streamLength, objectByteBuffer.capacity());
+
         objectByteBuffer.position(objectOffsetStart);
-        objectByteBuffer.limit(objectOffsetStart + streamLength);
-        streamByteBuffer.put(objectByteBuffer);
+        objectByteBuffer.limit(boundLimit);
+        ByteBuffer streamByteBuffer = objectByteBuffer.slice();
         objectByteBuffer.limit(oldLimit);
-        streamByteBuffer.flip();
         return streamByteBuffer;
     }
 

core/core-awt/src/main/java/org/icepdf/core/util/parser/object/Parser.java

@@ -46,7 +46,7 @@ public Parser(Library library) {
     public PObject getPObject(ByteBuffer byteBuffer, int objectOffsetStart)
             throws IOException, ObjectStateException {
 
-        int objectOffsetEnd = 0;
+        int objectOffsetEnd;
         int streamOffsetStart;
         int streamOffsetEnd;
         ByteBuffer streamByteBuffer;
@@ -61,9 +61,11 @@ public PObject getPObject(ByteBuffer byteBuffer, int objectOffsetStart)
                 objectOffsetEnd = byteBuffer.position() - XREF_MARKER.length;
             }
             // scan looking for the stream object end
-            // copy the bytes to a new buffer so we can work on the bytes without thread position issues.
-            streamByteBuffer = ByteBufferUtil.copyObjectStreamSlice(byteBuffer, objectOffsetStart, objectOffsetEnd);
+            // copy the bytes to a new buffer, so we can work on the bytes without thread position issues.
+            streamByteBuffer = ByteBufferUtil.sliceObjectStream(byteBuffer, objectOffsetStart, objectOffsetEnd);
         }
+        // todo mark the stream position, no need for a buffer yet, already have one
+
         // grab the pieces of the object
         Lexer lexer = new Lexer(library);
         lexer.setByteBuffer(streamByteBuffer);
@@ -99,9 +101,17 @@ public PObject getPObject(ByteBuffer byteBuffer, int objectOffsetStart)
         Object streamOrEndObj = lexer.nextToken();
         if (streamOrEndObj instanceof Integer && ((Integer) streamOrEndObj) == OperandNames.OP_stream) {
             lexer.skipWhiteSpace();
+
+            // create a new buffer to encapsulate the stream data using the length
+
+            // look for garbage as before
+
+            // check if we have an end_stream marker as expected, correct offset if needed.
+
             // stream offset
             streamOffsetStart = streamByteBuffer.position();
             int streamLength = library.getInt((DictionaryEntries) objectData, Dictionary.LENGTH_KEY);
+
             // doublc check a streamLength = zero, some encoders are lazy and there is actually data.
             if (streamLength == 0 && (streamByteBuffer.limit() - END_STREAM_MARKER.length) - streamOffsetStart > 0) {
                 streamLength = (streamByteBuffer.limit() - END_STREAM_MARKER.length) - streamOffsetStart;
@@ -126,9 +136,7 @@ public PObject getPObject(ByteBuffer byteBuffer, int objectOffsetStart)
             // trim the buffer to the stream start end.
             streamByteBuffer.position(streamOffsetStart);
             streamByteBuffer.limit(streamOffsetEnd);
-            streamByteBuffer = streamByteBuffer.compact();
-            streamByteBuffer.position(0);
-            streamByteBuffer.limit(streamOffsetEnd - streamOffsetStart);
+            streamByteBuffer = streamByteBuffer.slice();
         } else {
             streamByteBuffer = null;
         }
@@ -157,17 +165,16 @@ public CrossReference getCrossReference(ByteBuffer byteBuffer, int starXref)
             // sometimes the offset is off just by a few bytes
             byteBuffer.position(starXref - 10);
             xrefPositionStart = byteBuffer.position();
+
             // make sure we have a xref declaration
-            int bytesLeft = byteBuffer.limit() - byteBuffer.position();
-            lookAheadBuffer = ByteBuffer.allocateDirect(Math.min(bytesLeft, 48));
-            while (lookAheadBuffer.hasRemaining()) {
-                lookAheadBuffer.put(byteBuffer.get());
-            }
-        }
-        lookAheadBuffer.flip();
-        boolean foundXrefMarker = ByteBufferUtil.findString(lookAheadBuffer, XREF_MARKER);
-        Lexer objectLexer = new Lexer(library);
-        synchronized (library.getMappedFileByteBufferLock()) {
+            int bytesLeft = Math.min(byteBuffer.limit() - byteBuffer.position(), 48);
+            byteBuffer.limit(byteBuffer.position() + bytesLeft);
+            lookAheadBuffer = byteBuffer.slice();
+            byteBuffer.limit(byteBuffer.capacity());
+
+            boolean foundXrefMarker = ByteBufferUtil.findString(lookAheadBuffer, XREF_MARKER);
+            Lexer objectLexer = new Lexer(library);
+
             // see if we found xref marking and thus an < 1.5 formatted xref table.
             if (foundXrefMarker) {
                 // update the xref position as we will have removed any white space.
@@ -197,7 +204,7 @@ private CrossReference parseCrossReferenceTable(DictionaryEntries dictionaryEntr
         // mark the xref start, so it can be used to write future /prev entries.
         int xrefStartPos = start;
         // allocate to a new buffer as the data is well-defined.
-        ByteBuffer xrefTableBuffer = ByteBufferUtil.copyObjectStreamSlice(byteBuffer, start, end);
+        ByteBuffer xrefTableBuffer = ByteBufferUtil.sliceObjectStream(byteBuffer, start, end);
         CrossReferenceTable crossReferenceTable = new CrossReferenceTable(library, dictionaryEntries, xrefStartPos);
         objectLexer.setByteBuffer(xrefTableBuffer);
         // parse the sub groupings

viewer/viewer-awt/src/main/java/org/icepdf/ri/common/SwingController.java

@@ -2903,7 +2903,7 @@ public void commonNewDocumentHandling(String fileDescription) {
         // values are SinglePage, OnceColumn, TwoColumnLeft, TwoColumnRight,
         // TwoPageLeft, TwoPageRight.
         Object tmp = catalog.getObject(Catalog.PAGELAYOUT_KEY);
-        if (tmp != null && tmp instanceof Name) {
+        if (tmp instanceof Name) {
             String pageLayout = ((Name) tmp).getName();
             int viewType = DocumentViewControllerImpl.ONE_PAGE_VIEW;
             if (pageLayout.equalsIgnoreCase("OneColumn")) {