Start work on device settings communication

device/idevicesettings.cpp

@@ -0,0 +1,76 @@
+#include "device/include/idevicesettings.h"
+
+using namespace icsneo;
+
+uint16_t IDeviceSettings::CalculateGSChecksum(const std::vector<uint8_t>& settings) {
+	uint16_t gs_crc = 0;
+	const uint16_t* p = (const uint16_t*)settings.data();
+	size_t words = settings.size();
+	if(words % 2 == 1)
+		return 0xFFFF; // Somehow settings is not word aligned
+	words /= 2;
+
+	while(words--) {
+		uint16_t temp = *p;
+
+		for (int i = 0; i < 16; i++) {
+			bool iBit = temp & 1;
+			
+			int iCrcNxt;
+			//CRCNXT = NXTBIT EXOR CRC_RG(15);
+			if (gs_crc & (1 << 15))
+				iCrcNxt = iBit ^ 1;
+			else
+				iCrcNxt = iBit;
+			iCrcNxt = iCrcNxt & 0x01;
+
+
+			// CRC_RG(15:1) = CRC_RG(14:0); // shift left by
+			gs_crc = gs_crc << 1;
+			gs_crc = gs_crc & 0xFFFE;// clear first bit
+
+			if (iCrcNxt)//CRC_RG(14:0) = CRC_RG(14:0) EXOR (4599hex);
+				gs_crc = gs_crc ^ 0xa001;
+
+			temp >>= 1;
+		}
+
+		p++;
+	}
+	return gs_crc;
+}
+
+void IDeviceSettings::refresh() {
+	std::vector<uint8_t> rxSettings;
+	bool ret = com->getSettingsSync(rxSettings);
+	if(ret) {
+		if(rxSettings.size() < 6) // We need to at least have the header of GLOBAL_SETTINGS
+			return;
+
+		constexpr size_t gs_size = 3 * sizeof(uint16_t);
+		size_t rxLen = rxSettings.size() - gs_size;
+
+		uint16_t gs_version = rxSettings[0] | (rxSettings[1] << 8);
+		uint16_t gs_len = rxSettings[2] | (rxSettings[3] << 8);
+		uint16_t gs_chksum = rxSettings[4] | (rxSettings[5] << 8);
+		rxSettings.erase(rxSettings.begin(), rxSettings.begin() + gs_size);
+
+		if(gs_version != 5) {
+			std::cout << "gs_version was " << gs_version << " instead of 5.\nPlease update your firmware." << std::endl;
+			return;
+		}
+
+		if(rxLen != gs_len) {
+			std::cout << "rxLen was " << rxLen << " and gs_len was " << gs_len << " while reading settings" << std::endl;
+			return;
+		}
+
+		if(gs_chksum != CalculateGSChecksum(rxSettings)) {
+			std::cout << "Checksum mismatch while reading settings" << std::endl;
+			return;
+		}
+		
+		settings = std::move(rxSettings);
+		settingsLoaded = true;
+	}
+}