amidi: add sysex-interval option

This patch adds a new option to amidi tool: sysex-interval.

It adds a delay (in milliseconds) in between each SysEx message - it searches
for a 0xF7 byte.

This is very useful when sending firmware updates to a remote device via SysEx
or any other use that requires this delay in between SysEx messages.

`amidi' manual was updated with an example usage as well.

Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

amidi/amidi.1

@@ -1,4 +1,4 @@
-.TH AMIDI 1 "16 Apr 2016"
+.TH AMIDI 1 "30 Aug 2016"
 
 .SH NAME
 amidi \- read from and write to ALSA RawMIDI ports
@@ -120,6 +120,12 @@ received MIDI commands.
 Does not ignore Clock bytes (F8h) when saving or printing received
 MIDI commands.
 
+.TP
+.I \-i, \-\-sysex-interval=mseconds
+Adds a delay in between each SysEx message sent to a device. It is
+useful when sending firmware updates via SysEx messages to a remote
+device.
+
 .SH EXAMPLES
 
 .TP
@@ -129,6 +135,14 @@ will send the MIDI commands in
 to port
 .I hw:0.
 
+.TP
+.B amidi \-p hw:1,0,0 -s firmware.syx \-i 100
+will send the MIDI commands in
+.I firmware.syx
+to port
+.I hw:1,0,0
+with 100 milliseconds delay in between each SysEx message.
+
 .TP
 .B amidi \-S 'F0 43 10 4C 00 00 7E 00 F7'
 sends an XG Reset to the default port.

amidi/amidi.c

@@ -52,6 +52,7 @@ static int receive_file;
 static int dump;
 static float timeout;
 static int stop;
+static int sysex_interval;
 static snd_rawmidi_t *input, **inputp;
 static snd_rawmidi_t *output, **outputp;
 
@@ -82,7 +83,8 @@ static void usage(void)
 		"-t, --timeout=seconds           exits when no data has been received\n"
 		"                                for the specified duration\n"
 		"-a, --active-sensing            include active sensing bytes\n"
-		"-c, --clock            include clock bytes\n");
+		"-c, --clock                     include clock bytes\n"
+		"-i, --sysex-interval=mseconds   delay in between each SysEx message\n");
 }
 
 static void version(void)
@@ -230,6 +232,47 @@ static void rawmidi_list(void)
 	snd_output_close(output);
 }
 
+static int send_midi_interleaved(void)
+{
+	int err;
+	char *data = send_data;
+	size_t buffer_size;
+	snd_rawmidi_params_t *param;
+	snd_rawmidi_status_t *st;
+
+	snd_rawmidi_status_alloca(&st);
+
+	snd_rawmidi_params_alloca(&param);
+	snd_rawmidi_params_current(output, param);
+	buffer_size = snd_rawmidi_params_get_buffer_size(param);
+
+	while (data < (send_data + send_data_length)) {
+		int len = send_data + send_data_length - data;
+		char *temp;
+
+		if (data > send_data) {
+			snd_rawmidi_status(output, st);
+			do {
+				/* 320 µs per byte as noted in Page 1 of MIDI spec */
+				usleep((buffer_size - snd_rawmidi_status_get_avail(st)) * 320);
+				snd_rawmidi_status(output, st);
+			} while(snd_rawmidi_status_get_avail(st) < buffer_size);
+			usleep(sysex_interval * 1000);
+		}
+
+		/* find end of SysEx */
+		if ((temp = memchr(data, 0xf7, len)) != NULL)
+			len = temp - data + 1;
+
+		if ((err = snd_rawmidi_write(output, data, len)) < 0)
+			return err;
+
+		data += len;
+	}
+
+	return 0;
+}
+
 static void load_file(void)
 {
 	int fd;
@@ -411,7 +454,7 @@ static void add_send_hex_data(const char *str)
 
 int main(int argc, char *argv[])
 {
-	static const char short_options[] = "hVlLp:s:r:S::dt:ac";
+	static const char short_options[] = "hVlLp:s:r:S::dt:aci:";
 	static const struct option long_options[] = {
 		{"help", 0, NULL, 'h'},
 		{"version", 0, NULL, 'V'},
@@ -425,6 +468,7 @@ int main(int argc, char *argv[])
 		{"timeout", 1, NULL, 't'},
 		{"active-sensing", 0, NULL, 'a'},
 		{"clock", 0, NULL, 'c'},
+		{"sysex-interval", 1, NULL, 'i'},
 		{ }
 	};
 	int c, err, ok = 0;
@@ -474,6 +518,9 @@ int main(int argc, char *argv[])
 		case 'c':
 			ignore_clock = 0;
 			break;
+		case 'i':
+			sysex_interval = atoi(optarg);
+			break;
 		default:
 			error("Try `amidi --help' for more information.");
 			return 1;
@@ -549,9 +596,16 @@ int main(int argc, char *argv[])
 			error("cannot set blocking mode: %s", snd_strerror(err));
 			goto _exit;
 		}
+		if (!sysex_interval) {
 			if ((err = snd_rawmidi_write(output, send_data, send_data_length)) < 0) {
 				error("cannot send data: %s", snd_strerror(err));
-			goto _exit;
+				return err;
+			}
+		} else {
+			if ((err = send_midi_interleaved()) < 0) {
+				error("cannot send data: %s", snd_strerror(err));
+				return err;
+			}
 		}
 	}