Avoid O(n) endpoint lookup for each URB submission

Author: cgutman

app/src/main/java/org/cgutman/usbip/service/AttachedDeviceContext.java

@@ -3,6 +3,8 @@
 import android.hardware.usb.UsbConfiguration;
 import android.hardware.usb.UsbDevice;
 import android.hardware.usb.UsbDeviceConnection;
+import android.hardware.usb.UsbEndpoint;
+import android.util.SparseArray;
 
 import org.cgutman.usbip.server.protocol.dev.UsbIpSubmitUrb;
 
@@ -13,6 +15,7 @@ public class AttachedDeviceContext {
     public UsbDevice device;
     public UsbDeviceConnection devConn;
     public UsbConfiguration activeConfiguration;
+    public SparseArray<UsbEndpoint> activeConfigurationEndpointsByNumDir;
     public ThreadPoolExecutor requestPool;
     public HashSet<UsbIpSubmitUrb> activeMessages;
 }

app/src/main/java/org/cgutman/usbip/service/UsbIpService.java

@@ -623,37 +623,9 @@ public void submitUrbRequest(Socket s, UsbIpSubmitUrb msg) {
 		else {
 			// Find the correct endpoint
 			UsbEndpoint selectedEndpoint = null;
-			if (context.activeConfiguration != null) {
-				for (int i = 0; i < context.activeConfiguration.getInterfaceCount(); i++) {
-					// Check each interface
-					UsbInterface iface = context.activeConfiguration.getInterface(i);
-					for (int j = 0; j < iface.getEndpointCount(); j++) {
-						// Check the endpoint number
-						UsbEndpoint endpoint = iface.getEndpoint(j);
-						if (msg.ep == endpoint.getEndpointNumber()) {
-							// Check the direction
-							if (msg.direction == UsbIpDevicePacket.USBIP_DIR_IN) {
-								if (endpoint.getDirection() != UsbConstants.USB_DIR_IN) {
-									continue;
-								}
-							}
-							else {
-								if (endpoint.getDirection() != UsbConstants.USB_DIR_OUT) {
-									continue;
-								}
-							}
-
-							// This the right endpoint
-							selectedEndpoint = endpoint;
-							break;
-						}
-					}
-
-					// Check if we found the endpoint on the last interface
-					if (selectedEndpoint != null) {
-						break;
-					}
-				}
+			if (context.activeConfigurationEndpointsByNumDir != null) {
+				int endptNumDir = msg.ep + (msg.direction == UsbIpDevicePacket.USBIP_DIR_IN ? UsbConstants.USB_DIR_IN : 0);
+				selectedEndpoint = context.activeConfigurationEndpointsByNumDir.get(endptNumDir);
 			}
 			else {
 				System.err.println("Attempted to transfer to non-control EP before SET_CONFIGURATION!");

app/src/main/java/org/cgutman/usbip/usb/UsbControlHelper.java

@@ -6,6 +6,7 @@
 import android.hardware.usb.UsbEndpoint;
 import android.hardware.usb.UsbInterface;
 import android.os.Build;
+import android.util.SparseArray;
 
 import org.cgutman.usbip.service.AttachedDeviceContext;
 
@@ -106,6 +107,18 @@ public static boolean handleInternalControlTransfer(AttachedDeviceContext device
 					// This is now the active configuration
 					deviceContext.activeConfiguration = config;
 
+					// Construct the cache of endpoint mappings
+					deviceContext.activeConfigurationEndpointsByNumDir = new SparseArray<>();
+					for (int j = 0; j < deviceContext.activeConfiguration.getInterfaceCount(); j++) {
+						UsbInterface iface = deviceContext.activeConfiguration.getInterface(j);
+						for (int k = 0; k < iface.getEndpointCount(); k++) {
+							UsbEndpoint endp = iface.getEndpoint(k);
+							deviceContext.activeConfigurationEndpointsByNumDir.put(
+									endp.getDirection() | endp.getEndpointNumber(),
+									endp);
+						}
+					}
+
 					System.out.println("Claiming all interfaces from new configuration: "+deviceContext.activeConfiguration.getId());
 					for (int j = 0; j < deviceContext.activeConfiguration.getInterfaceCount(); j++) {
 						UsbInterface iface = deviceContext.activeConfiguration.getInterface(j);