/*
   * Hidraw Userspace Example
   *
   * Copyright (c) 2010 Alan Ott <alan@signal11.us>
   * Copyright (c) 2010 Signal 11 Software
   *
   * The code may be used by anyone for any purpose,
   * and can serve as a starting point for developing
   * applications using hidraw.
   */
  
  /* Linux */
  #include <linux/types.h>
  #include <linux/input.h>
  #include <linux/hidraw.h>
  
  /*
   * Ugly hack to work around failing compilation on systems that don't
   * yet populate new version of hidraw.h to userspace.
   */
  #ifndef HIDIOCSFEATURE
  #warning Please have your distro update the userspace kernel headers
  #define HIDIOCSFEATURE(len)    _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x06, len)
  #define HIDIOCGFEATURE(len)    _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x07, len)
  #endif
  
  /* Unix */
  #include <sys/ioctl.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  #include <unistd.h>
  
  /* C */
  #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  #include <errno.h>
  
  const char *bus_str(int bus);
  
  int main(int argc, char **argv)
  {
  	int fd;
  	int i, res, desc_size = 0;
  	char buf[256];
  	struct hidraw_report_descriptor rpt_desc;
  	struct hidraw_devinfo info;
  
  	/* Open the Device with non-blocking reads. In real life,
  	   don't use a hard coded path; use libudev instead. */
  	fd = open("/dev/hidraw0", O_RDWR|O_NONBLOCK);
  
  	if (fd < 0) {
  		perror("Unable to open device");
  		return 1;
  	}
  
  	memset(&rpt_desc, 0x0, sizeof(rpt_desc));
  	memset(&info, 0x0, sizeof(info));
  	memset(buf, 0x0, sizeof(buf));
  
  	/* Get Report Descriptor Size */
  	res = ioctl(fd, HIDIOCGRDESCSIZE, &desc_size);
  	if (res < 0)
  		perror("HIDIOCGRDESCSIZE");
  	else
  		printf("Report Descriptor Size: %d
  ", desc_size);
  
  	/* Get Report Descriptor */
  	rpt_desc.size = desc_size;
  	res = ioctl(fd, HIDIOCGRDESC, &rpt_desc);
  	if (res < 0) {
  		perror("HIDIOCGRDESC");
  	} else {
  		printf("Report Descriptor:
  ");
  		for (i = 0; i < rpt_desc.size; i++)
  			printf("%hhx ", rpt_desc.value[i]);
  		puts("
  ");
  	}
  
  	/* Get Raw Name */
  	res = ioctl(fd, HIDIOCGRAWNAME(256), buf);
  	if (res < 0)
  		perror("HIDIOCGRAWNAME");
  	else
  		printf("Raw Name: %s
  ", buf);
  
  	/* Get Physical Location */
  	res = ioctl(fd, HIDIOCGRAWPHYS(256), buf);
  	if (res < 0)
  		perror("HIDIOCGRAWPHYS");
  	else
  		printf("Raw Phys: %s
  ", buf);
  
  	/* Get Raw Info */
  	res = ioctl(fd, HIDIOCGRAWINFO, &info);
  	if (res < 0) {
  		perror("HIDIOCGRAWINFO");
  	} else {
  		printf("Raw Info:
  ");
  		printf("\tbustype: %d (%s)
  ",
  			info.bustype, bus_str(info.bustype));
  		printf("\tvendor: 0x%04hx
  ", info.vendor);
  		printf("\tproduct: 0x%04hx
  ", info.product);
  	}
  
  	/* Set Feature */
  	buf[0] = 0x9; /* Report Number */
  	buf[1] = 0xff;
  	buf[2] = 0xff;
  	buf[3] = 0xff;
  	res = ioctl(fd, HIDIOCSFEATURE(4), buf);
  	if (res < 0)
  		perror("HIDIOCSFEATURE");
  	else
  		printf("ioctl HIDIOCGFEATURE returned: %d
  ", res);
  
  	/* Get Feature */
  	buf[0] = 0x9; /* Report Number */
  	res = ioctl(fd, HIDIOCGFEATURE(256), buf);
  	if (res < 0) {
  		perror("HIDIOCGFEATURE");
  	} else {
  		printf("ioctl HIDIOCGFEATURE returned: %d
  ", res);
  		printf("Report data (not containing the report number):
  \t");
  		for (i = 0; i < res; i++)
  			printf("%hhx ", buf[i]);
  		puts("
  ");
  	}
  
  	/* Send a Report to the Device */
  	buf[0] = 0x1; /* Report Number */
  	buf[1] = 0x77;
  	res = write(fd, buf, 2);
  	if (res < 0) {
  		printf("Error: %d
  ", errno);
  		perror("write");
  	} else {
  		printf("write() wrote %d bytes
  ", res);
  	}
  
  	/* Get a report from the device */
  	res = read(fd, buf, 16);
  	if (res < 0) {
  		perror("read");
  	} else {
  		printf("read() read %d bytes:
  \t", res);
  		for (i = 0; i < res; i++)
  			printf("%hhx ", buf[i]);
  		puts("
  ");
  	}
  	close(fd);
  	return 0;
  }
  
  const char *
  bus_str(int bus)
  {
  	switch (bus) {
  	case BUS_USB:
  		return "USB";
  		break;
  	case BUS_HIL:
  		return "HIL";
  		break;
  	case BUS_BLUETOOTH:
  		return "Bluetooth";
  		break;
  	case BUS_VIRTUAL:
  		return "Virtual";
  		break;
  	default:
  		return "Other";
  		break;
  	}
  }