1 #include <unistd.h>
2 #include <sys/time.h>
3 #include <alsa/asoundlib.h>
4 #include <alsa/seq.h>
5
normalize(struct timeval * tv)6 void normalize(struct timeval *tv)
7 {
8 if (tv->tv_sec == 0) {
9 while (tv->tv_usec <= -1000000) { tv->tv_usec += 1000000; --tv->tv_sec; }
10 while (tv->tv_usec >= 1000000) { tv->tv_usec -= 1000000; ++tv->tv_sec; }
11 } else if (tv->tv_sec < 0) {
12 while (tv->tv_usec <= -1000000) { tv->tv_usec += 1000000; --tv->tv_sec; }
13 while (tv->tv_usec > 0) { tv->tv_usec -= 1000000; ++tv->tv_sec; }
14 } else {
15 while (tv->tv_usec >= 1000000) { tv->tv_usec -= 1000000; ++tv->tv_sec; }
16 while (tv->tv_usec < 0) { tv->tv_usec += 1000000; --tv->tv_sec; }
17 }
18 }
19
20 int
main(int argc ATTRIBUTE_UNUSED,char ** argv ATTRIBUTE_UNUSED)21 main(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
22 {
23 snd_seq_t *handle;
24 int portid;
25 /* int npfd;
26 struct pollfd *pfd;
27 */
28 int queue;
29 /* int i;
30 int rval;'
31 */
32 struct timeval starttv, prevdiff;
33 int countdown = -1;
34 /* snd_seq_queue_timer_t *timer;
35 snd_timer_id_t *timerid;
36 */
37
38 if (snd_seq_open(&handle, "hw", SND_SEQ_OPEN_DUPLEX, 0) < 0) {
39 fprintf(stderr, "failed to open ALSA sequencer interface\n");
40 return 1;
41 }
42
43 snd_seq_set_client_name(handle, "generator");
44
45 if ((portid = snd_seq_create_simple_port
46 (handle, "generator",
47 SND_SEQ_PORT_CAP_READ | SND_SEQ_PORT_CAP_SUBS_READ, 0)) < 0) {
48 fprintf(stderr, "failed to create ALSA sequencer port\n");
49 return 1;
50 }
51
52 if ((queue = snd_seq_alloc_queue(handle)) < 0) {
53 fprintf(stderr, "failed to create ALSA sequencer queue\n");
54 return 1;
55 }
56 /*
57 snd_seq_queue_timer_alloca(&timer);
58 snd_seq_get_queue_timer(handle, queue, timer);
59 snd_timer_id_alloca(&timerid);
60 snd_timer_id_set_class(timerid, SND_TIMER_CLASS_PCM);
61 snd_timer_id_set_sclass(timerid, SND_TIMER_SCLASS_NONE);
62 snd_timer_id_set_card(timerid, 0);
63 snd_timer_id_set_device(timerid, 0);
64 snd_timer_id_set_subdevice(timerid, 0);
65 snd_seq_queue_timer_set_id(timer, timerid);
66 snd_seq_set_queue_timer(handle, queue, timer);
67 */
68 snd_seq_start_queue(handle, queue, 0);
69 snd_seq_drain_output(handle);
70
71 gettimeofday(&starttv, 0);
72 prevdiff.tv_sec = 0;
73 prevdiff.tv_usec = 0;
74
75 while (countdown != 0) {
76
77 snd_seq_queue_status_t *status;
78 const snd_seq_real_time_t *rtime;
79 struct timeval tv, diff, diffdiff;
80 struct timespec ts;
81
82 snd_seq_queue_status_alloca(&status);
83
84 snd_seq_get_queue_status(handle, queue, status);
85 rtime = snd_seq_queue_status_get_real_time(status);
86
87 gettimeofday(&tv, 0);
88
89 tv.tv_sec -= starttv.tv_sec;
90 tv.tv_usec -= starttv.tv_usec;
91 normalize(&tv);
92
93 diff.tv_sec = tv.tv_sec - rtime->tv_sec;
94 diff.tv_usec = tv.tv_usec - rtime->tv_nsec / 1000;
95 normalize(&diff);
96
97 diffdiff.tv_sec = diff.tv_sec - prevdiff.tv_sec;
98 diffdiff.tv_usec = diff.tv_usec - prevdiff.tv_usec;
99 normalize(&diffdiff);
100 prevdiff = diff;
101
102 fprintf(stderr, " real time: %12ld sec %8ld usec\nqueue time: %12ld sec %8ld usec\n diff: %12ld sec %8ld usec\n diffdiff: %12ld sec %8ld usec\n",
103 tv.tv_sec, tv.tv_usec,
104 (long)rtime->tv_sec, (long)rtime->tv_nsec / 1000,
105 diff.tv_sec, diff.tv_usec,
106 (long)diffdiff.tv_sec, (long)diffdiff.tv_usec);
107
108 if (diffdiff.tv_usec > 5000 ||
109 diffdiff.tv_usec < -5000) {
110 fprintf(stderr, "oops! queue slipped\n");
111 if (tv.tv_sec < 5) {
112 fprintf(stderr, "(ignoring in first few seconds)\n");
113 } else {
114 countdown = 2;
115 }
116 } else {
117 if (countdown > 0) --countdown;
118 }
119
120 fprintf(stderr, "\n");
121 // sleep(1);
122 ts.tv_sec = 0;
123 ts.tv_nsec = 500000000;
124 nanosleep(&ts, 0);
125 }
126 return EXIT_SUCCESS;
127 }
128
129