src/add-ons/input_server/devices/wacom/DeviceReader.h

   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                          fMaxPackedSize;
  62 };
  63 #endif // USB_DEVICE_MONITOR_H