Initial values for SPNs and unknown fields will have all their bits s…

…et to 1 as in certain cases an initial value of 0 is valid.
famez · Sep 16, 2018 · e41f50a · e41f50a
1 parent 33a2d83
commit e41f50a
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Showing 3 changed files with 6 additions and 3 deletions.
diff --git a/J1939/J1939Frame.cpp b/J1939/J1939Frame.cpp
@@ -88,7 +88,7 @@ void J1939Frame::encode(u32& identifier, u8* buffer, size_t& length) const {
 
 	identifier |= (prio << J1939_PRIORITY_OFFSET);
 
-	memset(buffer, 0 , length);
+	memset(buffer, 0xFF, length);
 
 	encodeData(buffer, length);
 

diff --git a/J1939/SPN/SPNNumeric.cpp b/J1939/SPN/SPNNumeric.cpp
@@ -22,7 +22,7 @@ namespace J1939 {
 
 SPNNumeric::SPNNumeric(u32 number, const std::string& name, size_t offset, double formatGain, double formatOffset, u8 byteSize, const std::string& units) :
     SPN(number, name, offset),
-	 mFormatGain(formatGain), mFormatOffset(formatOffset), mByteSize(byteSize), mUnits(units), mValue(0) {
+	 mFormatGain(formatGain), mFormatOffset(formatOffset), mByteSize(byteSize), mUnits(units), mValue(0xFFFFFFFF) {
 
 	ASSERT(byteSize > 0)
 	ASSERT(byteSize <= SPN_NUMERIC_MAX_BYTE_SYZE)

diff --git a/J1939/SPN/SPNStatus.cpp b/J1939/SPN/SPNStatus.cpp
@@ -19,10 +19,13 @@
 
 namespace J1939 {
 
-SPNStatus::SPNStatus(u32 number, const std::string& name, size_t offset, u8 bitOffset, u8 bitSize) : SPN(number, name, offset), mBitOffset(bitOffset), mBitSize(bitSize), mValue(0) {
+SPNStatus::SPNStatus(u32 number, const std::string& name, size_t offset, u8 bitOffset, u8 bitSize) : SPN(number, name, offset), mBitOffset(bitOffset), mBitSize(bitSize) {
 
 	ASSERT(mBitSize > 0)
 	ASSERT(mBitOffset + mBitSize <= 8)
+
+	mValue = (0xFF >> (8 - mBitSize));		//Always initialized to invalid value
+
 }
 
 SPNStatus::~SPNStatus() {