1 /* 2 * Copyright 2005-2008 Stephan Aßmus <superstippi@gmx.de>. All rights reserved. 3 * Distributed under the terms of the MIT license. 4 */ 5 #ifndef USB_DEVICE_MONITOR_H 6 #define USB_DEVICE_MONITOR_H 7 8 9 // This class is designed to work with the generic USB input device driver 10 // the driver creates an entry in /dev/input/??? 11 // clients can open and read from the device file, the driver will than 12 // block on waiting for an interrupt transfer (timeout is 500 ms) and write 13 // the received data to the supplied buffer. In front of the buffer, it will 14 // write vendorID, productID and maxPacketSize, so you can read from the file 15 // with a buffer of just enough size to contain these fields, in this case, no 16 // interrupt transfer will be triggered, and the client can then configure itself 17 // with a more appropriate setup. 18 19 #include <SupportDefs.h> 20 21 class BFile; 22 class BString; 23 24 class DeviceReader { 25 public: 26 DeviceReader(); 27 virtual ~DeviceReader(); 28 29 // initializes the object 30 // by trying to read from the supplied device file 31 // on success (B_OK), all member variables will be set 32 // and the object is ready for operation 33 // on failure, a hopefully meaningful error is returned 34 virtual status_t SetTo(const char* path); 35 36 virtual status_t InitCheck() const; 37 38 const char* DevicePath() const; 39 BFile* DeviceFile() const; 40 41 // query the device for information 42 uint16 VendorID() const; 43 uint16 ProductID() const; 44 45 size_t MaxPacketSize() const; 46 47 // trigger an interrupt transfer and write the data in the buffer 48 // it should be save to call this function with 49 // size != MaxPacketSize, remaining bytes will be zero'd out 50 ssize_t ReadData(uint8* data, 51 const size_t size) const; 52 53 protected: 54 void _Unset(); 55 56 char* fDevicePath; 57 BFile* fDeviceFile; 58 59 uint16 fVendorID; 60 uint16 fProductID; 61 size_t fMaxPacketSize; 62 }; 63 #endif // USB_DEVICE_MONITOR_H 64