In one of the Windows system header files, an "interface" macro is
defined as:
#define interface struct
This results in some very strange build errors when also including the
descriptor-private.h header file. That's because the dc_usb_params_t
struct has a member field named "interface":
typedef struct dc_usb_params_t {
unsigned int interface;
unsigned char endpoint_in;
unsigned char endpoint_out;
} dc_usb_params_t;
As a workaround, define the WIN32_LEAN_AND_MEAN macro before including
the windows.h header file. This excludes some less common Windows API
declarations, including the above one.
There is no reason for libusb to ever return a negative number of bytes,
but due to the use of a signed integer, it's technically possible. And
because libdivecomputer returns an unsigned integer, such a negative
number would be reported as a very large size.
The USB communication is now also implemented as an I/O stream
transport. Unlike most I/O devices, USB communication supports multiple
interfaces and endpoints. This requires some some special care:
In the general case, autodetection isn't really possible without
additional knowledge. Hence the need for the filter parameters to pass
this kind of information.
The implementation assumes two bulk endpoints for the standard
read/write interface. Communication with the control endpoint is
supported through the new DC_IOCTL_USB_CONTROL_{READ,WRITE} ioctl's.
