Update Issue 4

New option -z provides requested functionality.
gcstang · Sep 12, 2012 · d46353a · d46353a
1 parent 808c5f2
commit d46353a
Show file tree

Hide file tree

Showing 2 changed files with 23 additions and 8 deletions.
diff --git a/src/main/java/com/nothome/delta/GDiffWriter.java b/src/main/java/com/nothome/delta/GDiffWriter.java
@@ -59,6 +59,7 @@ public class GDiffWriter implements DiffWriter {
     private boolean debug = false;
     private boolean skipHeaders = false;
     private boolean differential = false;
+    private boolean zeroAdditions = false;
     private long currentOffset = 0l;
     private long written = 0;
     private int data_max = DATA_MAX;
@@ -71,19 +72,22 @@ public class GDiffWriter implements DiffWriter {
 
     /**
      * Constructs a new GDiffWriter.
+     * @param os
+     * @throws IOException  
      */
     public GDiffWriter(DataOutputStream os) throws IOException {
-        this(os, false, false);
+        this(os, false, false, false);
     }
 
     public GDiffWriter(DataOutputStream os, boolean skipHeaders) throws IOException {
-        this(os, skipHeaders, false);
+        this(os, skipHeaders, false, false);
     }
 
-    public GDiffWriter(DataOutputStream os, boolean skipHeaders, boolean differential) throws IOException {
+    public GDiffWriter(DataOutputStream os, boolean skipHeaders, boolean differential, boolean zeroAdditions) throws IOException {
         this.differential = differential;
         this.output = os;
         this.skipHeaders = skipHeaders;
+        this.zeroAdditions = zeroAdditions;
         // write magic string "d1 ff d1 ff 04"
         if (!skipHeaders) {
             output.writeByte(0xd1);
@@ -195,7 +199,11 @@ public void addCopy(long offset, int length) throws IOException {
      */
     @Override
     public void addData(byte b) throws IOException {
-        buf.write(b);
+        if (zeroAdditions) {
+            buf.write(0);
+        } else {
+            buf.write(b);
+        }
         if (buf.size() >= CHUNK_SIZE) {
             writeBuf();
         }

diff --git a/src/main/java/org/mantlik/xdeltaencoder/XDeltaEncoder.java b/src/main/java/org/mantlik/xdeltaencoder/XDeltaEncoder.java
@@ -89,6 +89,7 @@ public class XDeltaEncoder {
     private static boolean multiBuffer = false;
     private static File oldDeltaReference = null;
     private static CompareOutputStream compareStream;
+    private static boolean zeroAdditions = false;
 
     private static void encode(int blocksize) throws FileNotFoundException, IOException, SQLException, ClassNotFoundException {
         ByteBuffer sourcebuf = ByteBuffer.wrap(new byte[2 * blocksize]);
@@ -192,7 +193,7 @@ private static void encodeVirtual(int blocksize) throws FileNotFoundException, I
         tStream = new BufferedInputStream(new FileInputStream(target));
         DiffWriter ddStream;
         if (source.length() < blocksize && (!preparation_pass)) {
-            ddStream = new GDiffWriter(new DataOutputStream(new GZIPOutputStream(new FileOutputStream(delta))), false, differential);
+            ddStream = new GDiffWriter(new DataOutputStream(new GZIPOutputStream(new FileOutputStream(delta))), false, differential, zeroAdditions);
         } else {
             ddStream = new VirtualWriter(new DataOutputStream(new BufferedOutputStream(new FileOutputStream(tempFile1))));
         }
@@ -255,7 +256,7 @@ private static void encodeVirtual(int blocksize) throws FileNotFoundException, I
             sourcebuf.get(ss);
             SeekableSource sourceData = new ByteBufferSeekableSource(ss);
             if ((!preparation_pass) && (sourcepos + sourcesize) >= source.length()) {
-                ddStream = new GDiffWriter(new DataOutputStream(new GZIPOutputStream(new FileOutputStream(delta))), false, differential);
+                ddStream = new GDiffWriter(new DataOutputStream(new GZIPOutputStream(new FileOutputStream(delta))), false, differential, zeroAdditions);
             } else {
                 ddStream = new VirtualWriter(new DataOutputStream(new BufferedOutputStream(new FileOutputStream(tempFile2))));
             }
@@ -477,7 +478,7 @@ private static void encodeVirtualFile(long blocksize) throws FileNotFoundExcepti
             if (xdiff) {
                 ddStream = new XDiffWriter(new DataOutputStream(new GZIPOutputStream(new FileOutputStream(delta))));
             } else {
-                ddStream = new GDiffWriter(new DataOutputStream(new GZIPOutputStream(new FileOutputStream(delta))), false, differential);
+                ddStream = new GDiffWriter(new DataOutputStream(new GZIPOutputStream(new FileOutputStream(delta))), false, differential, zeroAdditions);
             }
         } else {
             ddStream = new VirtualWriter(new DataOutputStream(new BufferedOutputStream(new FileOutputStream(tempFile1), 1024 * 1024)));
@@ -640,7 +641,8 @@ private static void encodeVirtualFile(long blocksize) throws FileNotFoundExcepti
                 if (xdiff) {
                     ddStream = new XDiffWriter(new DataOutputStream(new GZIPOutputStream(new FileOutputStream(delta))));
                 } else {
-                    ddStream = new GDiffWriter(new DataOutputStream(new GZIPOutputStream(new FileOutputStream(delta))), false, differential);
+                    ddStream = new GDiffWriter(new DataOutputStream(new GZIPOutputStream(new FileOutputStream(delta)))
+                            , false, differential, zeroAdditions);
                 }
             } else {
                 ddStream = new VirtualWriter(new DataOutputStream(new BufferedOutputStream(new FileOutputStream(tempFile2))));
@@ -1285,6 +1287,9 @@ public static void main(String[] args) {
                     + "             -mb          multi-buffer source - can be faster but needs more memory\n"
                     + "         -t               test the best block size (deprecated)\n"
                     + "         -p               preprocess using full file size (can be slow)\n"
+                    + "         -z               zero additions instead of copying dest blocks\n"
+                    + "                              decoded destination will contain copied source data,\n"
+                    + "                              the rest will be filled in with zeroes.\n"
                     + "         -f               read source block from file in memory\n"
                     + "                          slower but needs less memory\n"
                     + "         -s               single pass encoding (deprecated)\n"
@@ -1348,6 +1353,8 @@ public static void main(String[] args) {
                 ignoreWarnings = true;
             } else if (args[arcbase].equalsIgnoreCase("-x")) {
                 xdiff = true;
+            } else if (args[arcbase].equalsIgnoreCase("-z")) {
+                zeroAdditions = true;
             } else if (args[arcbase].equalsIgnoreCase("-c")) {
                 arcbase++;
                 chunksize = Integer.decode(args[arcbase]);