Adding checkpoint and robustness improvements

1 files changed, 23 insertions, 3 deletions

diff --git a/yaffs_checkptrw.c b/yaffs_checkptrw.c
index 2f658e6..2f3f875 100644
--- a/yaffs_checkptrw.c
+++ b/yaffs_checkptrw.c
@@ -12,7 +12,7 @@
  */
 
 const char *yaffs_checkptrw_c_version =
-    "$Id: yaffs_checkptrw.c,v 1.13 2007-02-14 01:09:06 wookey Exp $";
+    "$Id: yaffs_checkptrw.c,v 1.14 2007-05-15 20:07:40 charles Exp $";
 
 
 #include "yaffs_checkptrw.h"
@@ -32,7 +32,6 @@ static int yaffs_CheckpointSpaceOk(yaffs_Device *dev)
 }
 
 
-
 static int yaffs_CheckpointErase(yaffs_Device *dev)
 {
 	
@@ -153,6 +152,8 @@ int yaffs_CheckpointOpen(yaffs_Device *dev, int forWriting)
 	dev->checkpointOpenForWrite = forWriting;
 	
 	dev->checkpointByteCount = 0;
+	dev->checkpointSum = 0;
+	dev->checkpointXor = 0;
 	dev->checkpointCurrentBlock = -1;
 	dev->checkpointCurrentChunk = -1;
 	dev->checkpointNextBlock = dev->internalStartBlock;
@@ -180,6 +181,14 @@ int yaffs_CheckpointOpen(yaffs_Device *dev, int forWriting)
 	return 1;
 }
 
+int yaffs_GetCheckpointSum(yaffs_Device *dev, __u32 *sum)
+{
+	__u32 compositeSum;
+	compositeSum =  (dev->checkpointSum << 8) | (dev->checkpointXor & 0xFF);
+	*sum = compositeSum;
+	return 1;
+}
+
 static int yaffs_CheckpointFlushBuffer(yaffs_Device *dev)
 {
 
@@ -243,12 +252,18 @@ int yaffs_CheckpointWrite(yaffs_Device *dev,const void *data, int nBytes)
 
 	if(!dev->checkpointBuffer)
 		return 0;
+		
+	if(!dev->checkpointOpenForWrite)
+		return -1;
 
 	while(i < nBytes && ok) {
 		
 
 		
-		 dev->checkpointBuffer[dev->checkpointByteOffset] = *dataBytes ;
+		dev->checkpointBuffer[dev->checkpointByteOffset] = *dataBytes ;
+		dev->checkpointSum += *dataBytes;
+		dev->checkpointXor ^= *dataBytes;
+		 
 		dev->checkpointByteOffset++;
 		i++;
 		dataBytes++;
@@ -279,6 +294,9 @@ int yaffs_CheckpointRead(yaffs_Device *dev, void *data, int nBytes)
 	if(!dev->checkpointBuffer)
 		return 0;
 
+	if(dev->checkpointOpenForWrite)
+		return -1;
+
 	while(i < nBytes && ok) {
 	
 	
@@ -320,6 +338,8 @@ int yaffs_CheckpointRead(yaffs_Device *dev, void *data, int nBytes)
 		
 		if(ok){
 			*dataBytes = dev->checkpointBuffer[dev->checkpointByteOffset];
+			dev->checkpointSum += *dataBytes;
+			dev->checkpointXor ^= *dataBytes;
 			dev->checkpointByteOffset++;
 			i++;
 			dataBytes++;