format

* add length validation to the header

* fix accessing out of bound index with .at()

mlx/io/gguf.cpp

@@ -57,9 +57,16 @@ Shape get_shape(const gguf_tensor& tensor) {
 }
 
 std::tuple<allocator::Buffer, Dtype> extract_tensor_data(gguf_tensor* tensor) {
+  if (tensor == nullptr) {
+    throw std::invalid_argument(
+        "[extract_tensor_data] Input tensor pointer is null.");
+  }
   std::optional<Dtype> equivalent_dtype = gguf_type_to_dtype(tensor->type);
   // If there's an equivalent type, we can simply copy.
   if (equivalent_dtype.has_value()) {
+    if (tensor->weights_data == nullptr) {
+      throw std::runtime_error("[load_gguf] NULL tensor data pointer");
+    }
     allocator::Buffer buffer = allocator::malloc(tensor->bsize);
     memcpy(
         buffer.raw_ptr(),

mlx/io/load.cpp

@@ -265,7 +265,7 @@ array load(std::shared_ptr<io::Reader> in_stream, StreamOrDevice s) {
   std::vector<char> buffer(header_len + 1);
   in_stream->read(&buffer[0], header_len);
   buffer[header_len] = 0;
-  std::string header(&buffer[0]);
+  std::string header(buffer.data(), header_len);
 
   // Read data type from header
   std::string dtype_str = header.substr(11, 3);
@@ -273,7 +273,7 @@ array load(std::shared_ptr<io::Reader> in_stream, StreamOrDevice s) {
   Dtype dtype = dtype_from_array_protocol(dtype_str);
 
   // Read contiguity order
-  bool col_contiguous = header[34] == 'T';
+  bool col_contiguous = header.at(34) == 'T';
 
   // Read array shape from header
   Shape shape;