fix(opatIO): fixed header packing bug

src/opatIO/private/opatIO.cpp

@@ -11,6 +11,26 @@
 #include <limits>
 #include <deque>
 
+// Function to check system endianness
+bool is_big_endian() {
+    uint16_t test = 0x1;
+    return reinterpret_cast<uint8_t*>(&test)[0] == 0;
+}
+
+// Generic function to swap bytes for any type
+template <typename T>
+T swap_bytes(T value) {
+    static_assert(std::is_trivially_copyable<T>::value, "swap_bytes only supports trivial types.");
+    T result;
+    uint8_t* src = reinterpret_cast<uint8_t*>(&value);
+    uint8_t* dest = reinterpret_cast<uint8_t*>(&result);
+    for (size_t i = 0; i < sizeof(T); i++) {
+        dest[i] = src[sizeof(T) - 1 - i];
+    }
+    return result;
+}
+
+
 // Constructor
 OpatIO::OpatIO() {}
 
@@ -57,6 +77,12 @@ void OpatIO::readHeader(std::ifstream &file) {
     if (file.gcount() != sizeof(Header)) {
         throw std::runtime_error("Error reading header from file: " + filename);
     }
+
+    if (is_big_endian()) {
+        header.version = swap_bytes(header.version);
+        header.numTables = swap_bytes(header.numTables);
+        header.indexOffset = swap_bytes(header.indexOffset);
+    }
 }
 
 // Read the table index from the file
@@ -67,6 +93,7 @@ void OpatIO::readTableIndex(std::ifstream &file) {
     if (file.gcount() != static_cast<std::streamsize>(header.numTables * sizeof(TableIndex))) {
         throw std::runtime_error("Error reading table index from file: " + filename);
     }
+
     buildTableIDToComposition();
 }
 

src/opatIO/public/opatIO.h

@@ -9,6 +9,7 @@
 #include <map>
 #include <utility>
 
+#pragma pack(1)
 struct Header {
     char magic[4];
     uint16_t version;
@@ -21,6 +22,7 @@ struct Header {
     char reserved[26]; 
 };
 
+#pragma pack()
 struct TableIndex {
     double X;
     double Z;