typedef struct {
    // hyperparameters
    int B;
    int T;
    // input handling and its state
    FILE* tokens_file;
    long file_size;
    long current_position;
    // output memory
    int* batch;
    int* inputs;
    int* targets;
    // convenience variables
    int num_batches;
} DataLoader;

typedef struct {
    // hyperparameters
    int B;
    int T;
    // input handling and its state
    FILE* tokens_file;
    long file_size;
    long current_position;
    // output memory
    int* batch;
    int* inputs;
    int* targets;
    // convenience variables
    int num_batches;
} DataLoader;