Subversion Repositories group.electronics

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* this is libusb, see http://libusb.sourceforge.net/ */
#include <usb.h>

// Same as in main.c
#define USB_LED_OFF 100
#define USB_LED_ON  101

/* Used to get descriptor strings for device identification */
static int usbGetDescriptorString(usb_dev_handle *dev, int index, int langid, 
                                  char *buf, int buflen) {
    char buffer[256];
    int rval, i;

        // make standard request GET_DESCRIPTOR, type string and given index 
    // (e.g. dev->iProduct)
        rval = usb_control_msg(dev, 
        USB_TYPE_STANDARD | USB_RECIP_DEVICE | USB_ENDPOINT_IN, 
        USB_REQ_GET_DESCRIPTOR, (USB_DT_STRING << 8) + index, langid, 
        buffer, sizeof(buffer), 1000);
        
    if(rval < 0) // error
                return rval;
        
    // rval should be bytes read, but buffer[0] contains the actual response size
        if((unsigned char)buffer[0] < rval)
                rval = (unsigned char)buffer[0]; // string is shorter than bytes read
        
        if(buffer[1] != USB_DT_STRING) // second byte is the data type
                return 0; // invalid return type
                
        // we're dealing with UTF-16LE here so actual chars is half of rval,
        // and index 0 doesn't count
        rval /= 2;
        
        /* lossy conversion to ISO Latin1 */
        for(i = 1; i < rval && i < buflen; i++) {
                if(buffer[2 * i + 1] == 0)
                        buf[i-1] = buffer[2 * i];
                else
                        buf[i-1] = '?'; /* outside of ISO Latin1 range */
        }
        buf[i-1] = 0;
        
        return i-1;
}

static usb_dev_handle * usbOpenDevice(int vendor, char *vendorName, 
                                      int product, char *productName) {
        struct usb_bus *bus;
        struct usb_device *dev;
        char devVendor[256], devProduct[256];
    
        usb_dev_handle * handle = NULL;
        
        usb_init();
        usb_find_busses();
        usb_find_devices();
        
        for(bus=usb_get_busses(); bus; bus=bus->next) {
                for(dev=bus->devices; dev; dev=dev->next) {                     
                        
                        if(dev->descriptor.idVendor != vendor ||
                                dev->descriptor.idProduct != product)
                                continue;
                
                         /* we need to open the device in order to query strings */
                        if(!(handle = usb_open(dev))) {
                                fprintf(stderr, "Warning: cannot open USB device: %s\n",
                                usb_strerror());
                                continue;
                        }
            
                        /* get vendor name */
                        if(usbGetDescriptorString(handle, dev->descriptor.iManufacturer, 0x0409, devVendor, sizeof(devVendor)) < 0) {
                                fprintf(stderr, "Warning: cannot query manufacturer for device: %s\n", usb_strerror());
                                usb_close(handle);
                                continue;
                        }
            
                        /* get product name */
                        if(usbGetDescriptorString(handle, dev->descriptor.iProduct, 0x0409, devProduct, sizeof(devVendor)) < 0) {
                                fprintf(stderr, "Warning: cannot query product for device: %s\n", usb_strerror()); usb_close(handle);
                                continue;
                        }
            
                        if(strcmp(devVendor, vendorName) == 0 && strcmp(devProduct, productName) == 0)
                                return handle;
                        else
                                usb_close(handle);
                }
        }
        
        return NULL;
}

int main(int argc, char **argv) {
        usb_dev_handle *handle = NULL;
    int nBytes = 0;
    char buffer[256];

        if(argc < 2) {
                printf("Usage:\n");
                printf("usbtext on\n");
                printf("usbtext off\n");
                exit(1);
        }

        handle = usbOpenDevice(0x4242, "newioit.com.au", 0xe231, "Comm Selector");
        
        if(handle == NULL) {
                fprintf(stderr, "Could not find USB device!\n");
                exit(1);
        }

        if(strcmp(argv[1], "on") == 0) {
                nBytes = usb_control_msg(handle, 
            USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_IN, 
                        USB_LED_ON, 0, 0, (char *)buffer, sizeof(buffer), 5000);
        } else if(strcmp(argv[1], "off") == 0) {
                nBytes = usb_control_msg(handle, 
            USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_IN, 
                        USB_LED_OFF, 0, 0, (char *)buffer, sizeof(buffer), 5000);
        }
        
        if(nBytes < 0)
                fprintf(stderr, "USB error: %s\n", usb_strerror());
                
        usb_close(handle);
        
        return 0;
}