Method: Uhid#read

Defined in:
ext/uhid/uhid.c

#read ⇒ Object

Read data from the host.

All returned hashes contain the type key that specifies the type of the received packet. Valid types are: START, STOP, OPEN, CLOSE, OUTPUT. Only OUTPUT Hashes contain a data field that holds the data received by the host.



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# File 'ext/uhid/uhid.c', line 123

static VALUE
cuhid_read_data(VALUE self)
{
    ID file_var = rb_intern("@file");
    VALUE file = rb_ivar_get(self, file_var);
    Check_Type(file, T_FILE);
    VALUE file_fileno = rb_funcall(file, rb_intern("fileno"), 0);
    int fd = NUM2INT(file_fileno);

    struct uhid_event ev; 
    
    memset(&ev, 0, sizeof(ev));
    ssize_t ret = read(fd, &ev, sizeof(ev));

    if (ret == -1) { // EAGAIN
        return Qnil;
    }
    
    VALUE h = rb_hash_new();
    switch (ev.type) {
    case UHID_START:
        rb_hash_aset(h, rb_str_new_cstr("type"), rb_str_new_cstr("START"));
        return h;
    case UHID_STOP:
        rb_hash_aset(h, rb_str_new_cstr("type"), rb_str_new_cstr("STOP"));
        return h;
    case UHID_OPEN:
        rb_hash_aset(h, rb_str_new_cstr("type"), rb_str_new_cstr("OPEN"));
        return h;
    case UHID_CLOSE:
        rb_hash_aset(h, rb_str_new_cstr("type"), rb_str_new_cstr("CLOSE"));
        return h;
    case UHID_OUTPUT:
        rb_hash_aset(h, rb_str_new_cstr("type"), rb_str_new_cstr("OUTPUT"));
        rb_hash_aset(h, rb_str_new_cstr("data"), rb_str_new((const char *) ev.u.output.data, ev.u.output.size));
        return h;
    default:
        return Qnil;
    }
}