readinput_c.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <linux/input.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/select.h>
#include <sys/time.h>
#include <termios.h>
#include <signal.h>
#include <ruby.h>
#include <poll.h>


static VALUE t_init(VALUE self, VALUE device)
{
    int k_fd;
    int m_fd;
    char * path = RSTRING_PTR(device);
    if ((k_fd = open (path, O_RDONLY)) == -1)
        rb_raise(rb_eIOError, "Cannot open device %s", path);
    rb_iv_set(self, "@fd", INT2FIX(k_fd));
    return self;
}

static VALUE t_read(VALUE self)
{
    int fd = FIX2INT(rb_iv_get(self, "@fd"));

    int retval;
    struct pollfd rfds[1] =
    {
        {fd, POLLIN, 0}
    };


    retval = poll(rfds, 1, -1);

    if (retval == -1)
        rb_raise(rb_eIOError, "Poll error");
    else if (!retval)
        rb_raise(rb_eIOError, "No data");

    if (!(rfds[0].revents & POLLIN))
        rb_raise(rb_eIOError, "No descriptor ready");

    struct input_event ev[64];
    size_t size = sizeof(struct input_event);
    size_t maxSize = sizeof(ev);
    size_t readSize;

    if ((readSize = read(fd, ev, maxSize)) < size)
        rb_raise(rb_eIOError, "Cannot read on device");

    size_t i;
    for(i = 0; i < readSize / size; i++)
    {
        struct input_event *event = ev + i;
        printf("%d:%d", event->type, event->code);
        if (event->type == EV_KEY)
        {
            VALUE result = rb_funcall(self,
                                      rb_intern("create_event"),
                                      4,
                                      UINT2NUM(event->type),
                                      UINT2NUM(event->code),
                                      INT2NUM(event->value),
                                      rb_time_new(event->time.tv_sec, event->time.tv_usec));
            return result;
        }
    }

    return Qnil;
}

VALUE mReadInput;
VALUE cReader;

void Init_readinput_c()
{
    mReadInput = rb_define_module("ReadInput");
    cReader = rb_define_class_under(mReadInput, "Reader", rb_cObject);
    rb_define_method(cReader, "initialize", t_init, 1);
    rb_define_method(cReader, "read", t_read, 0);
}