ORC-1834: [C++] Fix undefined behavior

See #2112 Closes #2116 from georgthegreat/patch-4. Authored-by: Yuriy Chernyshov <[email protected]> Signed-off-by: Gang Wu <[email protected]>
apache · Jan 22, 2025 · 825f248 · 825f248
1 parent 6aea9ed
commit 825f248
Showing 1 changed file with 5 additions and 3 deletions.
diff --git a/c++/src/ColumnReader.cc b/c++/src/ColumnReader.cc
@@ -395,7 +395,7 @@ namespace orc {
       int64_t bits = 0;
       if (bufferEnd_ - bufferPointer_ >= 8) {
         if (isLittleEndian) {
-          bits = *(reinterpret_cast<const int64_t*>(bufferPointer_));
+          memcpy(&bits, bufferPointer_, sizeof(bits));
         } else {
           bits = static_cast<int64_t>(static_cast<unsigned char>(bufferPointer_[0]));
           bits |= static_cast<int64_t>(static_cast<unsigned char>(bufferPointer_[1])) << 8;
@@ -509,8 +509,10 @@ namespace orc {
           bufferNum = std::min(numValues,
                                static_cast<size_t>(bufferEnd_ - bufferPointer_) / bytesPerValue_);
           uint64_t bufferBytes = bufferNum * bytesPerValue_;
-          memcpy(outArray, bufferPointer_, bufferBytes);
-          bufferPointer_ += bufferBytes;
+          if (bufferBytes > 0) {
+            memcpy(outArray, bufferPointer_, bufferBytes);
+            bufferPointer_ += bufferBytes;
+          }
         }
         for (size_t i = bufferNum; i < numValues; ++i) {
           outArray[i] = readDouble<ValueType>();