Improve Checksum Fix processing

Author: aalesv

src/main/java/com/romraider/maps/Rom.java

@@ -271,7 +271,7 @@ public void populateTables(byte[] binData, JProgressPane progress) {
                         TableUpdateHandler.getInstance().registerTable(table);
 
                         if (null != table.getName() && table.getName().equalsIgnoreCase("Checksum Fix")){
-                            setEditStamp(binData, table.getStorageAddress());
+                            setEditStamp(binData, table.getStorageAddress() - table.getRamOffset());
                         }
                         i++;
                     } catch (ArrayIndexOutOfBoundsException ex) {
@@ -396,8 +396,7 @@ private void showChecksumFixPopup(TableTreeNode checksum) {
              //TODO: Move to Subaru checksum
              calculateRomChecksum(
                      binData,
-                     checksum.getTable().getStorageAddress(),
-                     checksum.getTable().getDataSize()
+                     checksum.getTable()
              );
          }
     }
@@ -406,14 +405,19 @@ private void showChecksumFixPopup(TableTreeNode checksum) {
     //It is only used to correct the Subaru Checksum. Should be moved somewhere else TODO
     public byte[] saveFile() {
 
+        //There can be more than 1 Checksum Fix tables, find them all
         final List<TableTreeNode> checksumTables = new ArrayList<TableTreeNode>();
-        if(tableNodes.containsKey("checksum fix")) {
-            checksumTables.add(tableNodes.get("checksum fix"));
+        for (String name: tableNodes.keySet()) {
+            if (name.startsWith("checksum fix")) {
+                checksumTables.add(tableNodes.get(name));
+            }
         }
 
         if (checksumTables.size() == 1) {
             final TableTreeNode checksum = checksumTables.get(0);
-            byte count = binData[checksum.getTable().getStorageAddress() + 207];
+            int binDataPos = checksum.getTable().getStorageAddress() -
+                             checksum.getTable().getRamOffset();
+            byte count = binData[binDataPos + 207];
             if (count == -1) {
                 count = 1;
             }
@@ -427,18 +431,17 @@ public byte[] saveFile() {
                     romStamp,
                     0,
                     binData,
-                    checksum.getTable().getStorageAddress() + 204,
+                    binDataPos + 204,
                     4);
-            setEditStamp(binData, checksum.getTable().getStorageAddress());
+            setEditStamp(binData, binDataPos);
         }
 
         for (TableTreeNode checksum : checksumTables) {
             if (!checksum.getTable().isLocked()) {
                 //TODO: Move to Subaru checksum
                 calculateRomChecksum(
                         binData,
-                        checksum.getTable().getStorageAddress(),
-                        checksum.getTable().getDataSize()
+                        checksum.getTable()
                 );
             }
             else if (checksum.getTable().isLocked() &&

src/main/java/com/romraider/maps/RomChecksum.java

@@ -26,23 +26,59 @@
 
 public class RomChecksum {
 
-    public static void calculateRomChecksum(byte[] input, int storageAddress, int dataSize) {
+    public static void calculateRomChecksum(byte[] input, Table table)
+    {
+        calculateRomChecksum(
+                    input,
+                    table.getStorageAddress(),
+                    table.getDataSize(),
+                    table.getRamOffset()
+        );
+    }
+
+    public static int validateRomChecksum(byte[] input, Table table)
+    {
+        return validateRomChecksum(
+                    input,
+                    table.getStorageAddress(),
+                    table.getDataSize(),
+                    table.getRamOffset()
+        );
+    }
+
+    private static void calculateRomChecksum(byte[] input, int storageAddress, int dataSize, int offset) {
+        storageAddress = storageAddress - offset;
         for (int i = storageAddress; i < storageAddress + dataSize; i+=12) {
+            int startAddr = (int)parseByteValue(input, Settings.Endian.BIG, i  , 4, true);
+            int endAddr   = (int)parseByteValue(input, Settings.Endian.BIG, i+4, 4, true);
+            int off = offset;
+            //0 means checksum is disabled, keep it
+            if (startAddr == 0 && endAddr == 0) {
+                off = 0;
+            }
             byte[] newSum = calculateChecksum(input,
-                    (int)parseByteValue(input, Settings.Endian.BIG, i  , 4, true),
-                    (int)parseByteValue(input, Settings.Endian.BIG, i+4, 4, true));
+                    startAddr - off,
+                    endAddr   - off);
             System.arraycopy(newSum, 0, input, i + 8, 4);
         }
     }
 
-    public static int validateRomChecksum(byte[] input, int storageAddress, int dataSize) {
+    private static int validateRomChecksum(byte[] input, int storageAddress, int dataSize, int offset) {
+        storageAddress = storageAddress - offset;
         int result = 0;
         int[] results = new int[dataSize / 12];
         int j = 0;
         for (int i = storageAddress; i < storageAddress + dataSize; i+=12) {
             int startAddr = (int)parseByteValue(input, Settings.Endian.BIG, i  , 4, true);
             int endAddr   = (int)parseByteValue(input, Settings.Endian.BIG, i+4, 4, true);
             int diff      = (int)parseByteValue(input, Settings.Endian.BIG, i+8, 4, true);
+            int off = offset;
+            //0 means checksum is disabled, keep it
+            if (startAddr == 0 && endAddr == 0) {
+                off = 0;
+            }
+            startAddr -= off;
+            endAddr   -= off;
             if (j == 0 &&
                     startAddr == 0 &&
                     endAddr   == 0 &&

src/main/java/com/romraider/maps/TableSwitch.java

@@ -54,8 +54,7 @@ public void populateTable(Rom rom) throws ArrayIndexOutOfBoundsException, IndexO
 	    // if the result is  0: all the checksums matched
 	    // if the result is -1: all the checksums have been previously disabled
 	    if (super.getName().contains("Checksum Fix")) {
-	        int result = validateRomChecksum(getDataCell(0).getBinary(),
-	        		getStorageAddress(), getDataSize());
+			int result = validateRomChecksum(getDataCell(0).getBinary(), this);
 
 	        String message = MessageFormat.format(
 	                rb.getString("CHKSUMINVALID"), result, super.getName());