add bar drawing, use pointers more

include/gpu.hpp

@@ -22,4 +22,11 @@ struct gpu_t {
 	uint8_t umc_usage;
 };
 
-gpu_t getGpu(std::string hw);
+struct GpuMetricsHeader_t {
+    uint16_t structure_size;
+    uint8_t format_revision;
+    uint8_t content_revision;
+};
+
+gpu_t getGpu(GpuMetricsHeader_t header, std::string hw);
+GpuMetricsHeader_t getGpuMetricsRev(std::string path);