[alsa-devel] [PATCH] amidi: add delay option

[Felipe F. Tonello]

This patch adds a new options to amidi tool to add a delay (in milliseconds)
to each MIDI message.

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

Signed-off-by: Felipe F. Tonello <eu at felipetonello.com>
---
 amidi/amidi.1 | 14 ++++++++++++
 amidi/amidi.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 81 insertions(+), 5 deletions(-)

diff --git a/amidi/amidi.1 b/amidi/amidi.1
index 1b4cfb1ea956..40402c17e374 100644
--- a/amidi/amidi.1
+++ b/amidi/amidi.1
@@ -111,6 +111,12 @@ to stop receiving data.
 Does not ignore Active Sensing bytes (FEh) when saving or printing
 received MIDI commands.
 
+.TP
+.I \-D, \-\-delay=mseconds
+Adds a delay in between each MIDI message sent to a device. It is
+useful when sending firmware updates via SysEx messages to a remote
+device.
+
 .SH EXAMPLES
 
 .TP
@@ -121,6 +127,14 @@ to port
 .I hw:0.
 
 .TP
+.B amidi \-p hw:1,0,0 -s firmware.syx \-D 100
+will send the MIDI commands in
+.I firmware.syx
+to port
+.I hw:1,0,0
+with 100 milliseconds delay in between MIDI messages.
+
+.TP
 .B amidi \-S 'F0 43 10 4C 00 00 7E 00 F7'
 sends an XG Reset to the default port.
 
diff --git a/amidi/amidi.c b/amidi/amidi.c
index cedf18c5fd39..f45abfa7eac0 100644
--- a/amidi/amidi.c
+++ b/amidi/amidi.c
@@ -48,6 +48,7 @@ static int receive_file;
 static int dump;
 static int timeout;
 static int stop;
+static int delay;
 static snd_rawmidi_t *input, **inputp;
 static snd_rawmidi_t *output, **outputp;
 
@@ -77,7 +78,8 @@ static void usage(void)
 		"-d, --dump             print received data as hexadecimal bytes\n"
 		"-t, --timeout=seconds  exits when no data has been received\n"
 		"                       for the specified duration\n"
-		"-a, --active-sensing   don't ignore active sensing bytes\n");
+		"-a, --active-sensing   don't ignore active sensing bytes\n"
+		"-D, --delay=mseconds   delay in between each sent MIDI message\n");
 }
 
 static void version(void)
@@ -305,6 +307,35 @@ static void parse_data(void)
 	send_data_length = i;
 }
 
+static int message_length(unsigned char byte)
+{
+	static int rstate_len = 0;
+
+	switch (byte) {
+	case 0xf8 ... 0xff:
+		return 1;
+	case 0xf0:
+		return -1; /* variable size */
+	case 0xf1:
+	case 0xf3:
+		return 2;
+	case 0xf2:
+		return 3;
+	case 0xf4:
+	case 0xf5:
+		return 0; /* ignore */
+	case 0xf6:
+		return 1;
+	case 0xf7:
+		return 0; /* ignore */
+	case 0x80 ... 0xef:
+		rstate_len = (byte >= 0xc0 && byte <= 0xdf) ? 2 : 3;
+		return rstate_len;
+	case 0x00 ... 0x7f:
+		return rstate_len ?: rstate_len - 1;
+	}
+}
+
 /*
  * prints MIDI commands, formatting them nicely
  */
@@ -406,7 +437,7 @@ 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:a";
+	static const char short_options[] = "hVlLp:s:r:S::dt:aD:";
 	static const struct option long_options[] = {
 		{"help", 0, NULL, 'h'},
 		{"version", 0, NULL, 'V'},
@@ -419,6 +450,7 @@ int main(int argc, char *argv[])
 		{"dump", 0, NULL, 'd'},
 		{"timeout", 1, NULL, 't'},
 		{"active-sensing", 0, NULL, 'a'},
+		{"delay", 1, NULL, 'D'},
 		{ }
 	};
 	int c, err, ok = 0;
@@ -463,6 +495,9 @@ int main(int argc, char *argv[])
 		case 'a':
 			ignore_active_sensing = 0;
 			break;
+		case 'D':
+			delay = atoi(optarg);
+			break;
 		default:
 			error("Try `amidi --help' for more information.");
 			return 1;
@@ -538,9 +573,36 @@ int main(int argc, char *argv[])
 			error("cannot set blocking mode: %s", snd_strerror(err));
 			goto _exit;
 		}
-		if ((err = snd_rawmidi_write(output, send_data, send_data_length)) < 0) {
-			error("cannot send data: %s", snd_strerror(err));
-			goto _exit;
+		if (!delay) {
+				if ((err = snd_rawmidi_write(output, send_data, send_data_length)) < 0) {
+					error("cannot send data: %s", snd_strerror(err));
+					return err;
+				}
+		} else {
+			unsigned char *data = (unsigned char *)send_data;
+
+			while (data < ((unsigned char *)send_data + send_data_length)) {
+
+				if (data > (unsigned char *)send_data)
+					usleep(delay * 1000);
+
+				int len = message_length(*data);
+
+				/* check for variable length */
+				if (len == -1) {
+					int i = 0;
+					while (data[i++] != 0xf7);
+					len = i;
+				}
+
+				if (len > 0 &&
+				    (err = snd_rawmidi_write(output, data, len)) < 0) {
+					error("cannot send data: %s", snd_strerror(err));
+					return err;
+				}
+
+				data += len ?: 1;
+			}
 		}
 	}
 
-- 
2.9.2