Closes #16

core/dbc_decoder.cpp

@@ -10,6 +10,7 @@
  */
 
 #include "dbc_decoder.h"
+#include "signal_layout.h"
 #include <cmath>
 #include <utility>
 
@@ -58,11 +59,8 @@ bool DbcDecoder::IsValidDefinition(const DecodeSignal &signal, std::uint8_t dlc)
          signal.multiplexing.role != MultiplexRole::Branch))
         return false;
 
-    // Use widened coordinates to avoid overflow on malformed start bits.
-    const std::uint64_t start = signal.byteOrder == ByteOrder::Intel
-                                    ? signal.startBit
-                                    : std::uint64_t(signal.startBit / 8U) * 8U + 7U - signal.startBit % 8U;
-    return start + signal.length <= std::uint64_t(dlc) * 8U;
+    return IsValidSignalLayout(signal.startBit, signal.length,
+                              signal.byteOrder == ByteOrder::Intel, dlc);
 }
 
 DbcDecoder::SelectorState DbcDecoder::ReadSelector(const DecodeFrame &definition,
@@ -154,8 +152,8 @@ bool DbcDecoder::ExtractIntel(const std::vector<std::uint8_t> &data,
     value = 0U;
 
     for (std::uint32_t bitIndex = 0U; bitIndex < length; ++bitIndex) {
-        const std::uint32_t absoluteBit = startBit + bitIndex;
-        const std::uint32_t byteIndex = absoluteBit / 8U;
+        const std::uint64_t absoluteBit = std::uint64_t(startBit) + bitIndex;
+        const std::uint64_t byteIndex = absoluteBit / 8U;
         const std::uint32_t bitInByte = absoluteBit % 8U;
 
         if (byteIndex >= data.size())