+// ----------------------------------------------------------------------------
+// Data input / Update
+// ----------------------------------------------------------------------------
+/**
+ * \brief Read a set amounts of bits from a stream
+ * \param Data Base of data
+ * \param Offset Bit offset
+ * \param Length Number of bits to read
+ * \return Sign-extended value
+ */
+Sint32 _ReadBits(void *Data, int Offset, int Length)
+{
+ int dest_ofs = 0;
+ int rem = Length;
+ Uint32 rv = 0;
+ Uint8 *bytes = (Uint8*)Data + Offset / 8;
+
+ // Sanity please
+ if( Length > 32 ) return 0;
+
+ // Leading byte
+ if( Offset & 7 )
+ {
+ if( Length < 8 - (Offset & 7) )
+ {
+ rv = (*bytes >> Offset) & ((1 << Length)-1);
+ goto _ext;
+ }
+
+ rv = (*bytes >> Offset);
+
+ dest_ofs = Offset & 7;
+ rem = Length - (Offset & 7);
+ bytes ++;
+ }
+
+ // Body bytes
+ while( rem >= 8 )
+ {
+ rv |= *bytes << dest_ofs;
+ dest_ofs += 8;
+ rem -= 8;
+ bytes ++;
+ }
+
+ if( rem )
+ {
+ rv |= (*bytes & ((1 << rem)-1)) << dest_ofs;
+ }
+
+ // Do sign extension
+_ext:
+ if( rv & (1 << (Length-1)) )
+ rv |= 0xFFFFFFFF << Length;
+ return rv;
+}
+
+/**
+ * \brief Handle an update from the device
+ */
+void HID_Mouse_DataAvail(tUSBInterface *Dev, int EndPt, int Length, void *Data)
+{
+ tHID_Mouse *info;
+ int ofs;
+ Uint32 button_value = 0;
+ int axis_values[MAX_AXIES] = {0};
+
+ info = USB_GetDeviceDataPtr(Dev);
+ if( !info ) return ;
+
+ ofs = 0;
+ for( int i = 0; i < info->nMappings; i ++ )
+ {
+ Sint32 value;
+ Uint8 dest = info->Mappings[i].Dest;
+
+ if( ofs + info->Mappings[i].BitSize > Length * 8 )
+ return ;
+
+ value = _ReadBits(Data, ofs, info->Mappings[i].BitSize);
+ LOG("%i+%i: value = %i", ofs, info->Mappings[i].BitSize, value);
+ ofs += info->Mappings[i].BitSize;
+
+ if( dest == 0xFF ) continue ;
+
+ if( dest & 0x80 )
+ {
+ // Axis
+ axis_values[ dest & 0x7F ] = value;
+ LOG("Axis %i = %i", dest & 0x7F, value);
+ }
+ else
+ {
+ // Button
+ if( value == 0 )
+ ;
+ else
+ button_value |= 1 << (dest & 0x7F);
+ }
+ }
+
+ Mouse_HandleEvent(info->Handle, button_value, axis_values);
+}
+
+// ----------------------------------------------------------------------------
+// Device initialisation
+// ----------------------------------------------------------------------------
+/**
+ * \brief Handle the opening of a collection
+ */