Create evhz.c

diff --git a/evhz.c b/evhz.c
new file mode 100644 (file)
index 0000000..a7a42be
--- /dev/null
+++ b/evhz.c
@@ -0,0 +1,112 @@
+#include <stdio.h>
+#include <linux/input.h>
+#include <fcntl.h>
+#include <signal.h>
+
+#define EVENTS 10
+#define HZ_LIST 64
+
+typedef struct event_s {
+       int fd;
+       int hz[HZ_LIST];
+       int count;
+       double prvtime;
+} event_t;
+
+int quit = 0;
+
+void sigint() {
+       signal(SIGINT, sigint);
+       quit = 1;
+}
+
+int main(int argc, char **argv) {
+       int i;
+       event_t events[EVENTS];
+
+       signal(SIGINT, sigint);
+
+       printf("Press CTRL-C to exit.\n\n");
+
+       memset(events, 0, sizeof(events));
+
+       for(i = 0; i < EVENTS; i++) {
+               char device[18];
+
+               sprintf(device, "/dev/input/event%i", i);
+               events[i].fd = open(device, O_RDONLY);
+               
+               if(events[i].fd != -1) {
+                       char name[128];
+                       ioctl(events[i].fd, EVIOCGNAME(sizeof(name)), name);
+                       printf("event%i: %s\n", i, name);
+               }
+       }
+
+       while(!quit) {
+               fd_set set;
+
+               FD_ZERO(&set);
+
+               for(i = 0; i < EVENTS; i++) {
+                       if(events[i].fd != -1) {
+                               FD_SET(events[i].fd, &set);
+                       }
+               }
+
+               if(select(FD_SETSIZE, &set, NULL, NULL, NULL) > 0) {
+                       int bytes;
+                       struct input_event event;
+
+                       for(i = 0; i < EVENTS; i++) {
+                               if(events[i].fd == -1) {
+                                       continue;
+                               }
+
+                               if(!FD_ISSET(events[i].fd, &set)) {
+                                       continue;
+                               }
+
+                               bytes = read(events[i].fd, &event, sizeof(event));
+
+                               if(bytes != sizeof(event)) {
+                                       continue;
+                               }
+
+                               if(event.type == EV_REL) {
+                                       double time;
+                                       int hz;
+
+                                       time = event.time.tv_sec * 1000 + event.time.tv_usec / 1000;
+                                       hz = 1000 / (time - events[i].prvtime);
+
+                                       if(hz > 0) {
+                                               int avghz;
+                                               int j;
+
+                                               events[i].count++;
+                                               events[i].hz[events[i].count & (HZ_LIST - 1)] = hz;
+
+                                               avghz = 0;
+
+                                               for(j = 0; j < HZ_LIST; j++) {
+                                                       avghz += events[i].hz[j];
+                                               }
+
+                                               avghz /= (events[i].count > HZ_LIST) ? HZ_LIST : events[i].count;
+
+                                               printf("event%i: latest hz = %i (average hz = %i)\n", i, hz, avghz);
+                                       }
+
+                                       events[i].prvtime = time;
+                               }
+                       }
+               }
+       }
+
+       for(i = 0; i < EVENTS; i++) {
+               if(events[i].fd != -1) {
+                       close(events[i].fd);
+               }
+       }
+}