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-rw-r--r--backends/rtpmidi.c155
1 files changed, 153 insertions, 2 deletions
diff --git a/backends/rtpmidi.c b/backends/rtpmidi.c
index 4966a79..611d99b 100644
--- a/backends/rtpmidi.c
+++ b/backends/rtpmidi.c
@@ -134,6 +134,22 @@ static int rtpmidi_bind_instance(rtpmidi_instance_data* data, char* host, char*
return 0;
}
+static char* rtpmidi_type_name(uint8_t type){
+ switch(type){
+ case note:
+ return "note";
+ case cc:
+ return "cc";
+ case pressure:
+ return "pressure";
+ case aftertouch:
+ return "aftertouch";
+ case pitchbend:
+ return "pitch";
+ }
+ return "unknown";
+}
+
static int rtpmidi_push_peer(rtpmidi_instance_data* data, struct sockaddr_storage sock_addr, socklen_t sock_len){
size_t u, p = data->peers;
@@ -616,14 +632,145 @@ static int rtpmidi_handle_applemidi(instance* inst, int fd, uint8_t* frame, size
return 0;
}
+static int rtpmidi_parse(instance* inst, uint8_t* frame, size_t bytes){
+ uint16_t length = 0;
+ size_t offset = 1, decode_time = 0, command_bytes = 0;
+ uint8_t midi_status = 0;
+ rtpmidi_channel_ident ident;
+ channel_value val;
+ channel* chan = NULL;
+
+ if(!bytes){
+ LOGPF("No command section in data on instance %s", inst->name);
+ return 1;
+ }
+
+ //calculate midi command section length
+ length = frame[0] & 0x0F;
+ if(frame[0] & 0x80){
+ //extended header
+ if(bytes < 2){
+ LOGPF("Short command section (%" PRIsize_t " bytes) on %s, missing extended header", bytes, inst->name);
+ return 1;
+ }
+ length <<= 8;
+ length |= frame[1];
+ offset = 2;
+ }
+
+ command_bytes = offset + length;
+ DBGPF("%u/%" PRIsize_t " bytes of command section on %s, %s header, %s initial dtime",
+ length, bytes, inst->name,
+ (frame[0] & 0x80) ? "extended" : "normal",
+ (frame[0] & 0x20) ? "has" : "no");
+
+ if(command_bytes > bytes){
+ LOGPF("Short command section on %s, indicated %" PRIsize_t ", had %" PRIsize_t, inst->name, command_bytes, bytes);
+ return 1;
+ }
+
+ if(frame[0] & 0x20){
+ decode_time = 1;
+ }
+
+ do{
+ //decode delta-time
+ if(decode_time){
+ for(; offset < command_bytes && frame[offset] & 0x80; offset++){
+ }
+ offset++;
+ }
+
+ //section 3 of rfc6295 states that the first dtime as well as the last command may be omitted
+ //this may make sense on a low-speed serial line, but on a network... come on.
+ if(offset >= command_bytes){
+ break;
+ }
+
+ //check for a status byte
+ //TODO filter sysex
+ if(frame[offset] & 0x80){
+ midi_status = frame[offset];
+ offset++;
+ }
+
+ //having variable encoding in each and every component is super annoying to check for...
+ if(offset >= command_bytes){
+ break;
+ }
+
+ ident.label = 0;
+ ident.fields.type = midi_status & 0xF0;
+ ident.fields.channel = midi_status & 0x0F;
+
+ //single byte command
+ if(ident.fields.type == aftertouch){
+ ident.fields.control = 0;
+ val.normalised = (double) frame[offset] / 127.0;
+ offset++;
+ }
+ //two-byte command
+ else{
+ offset++;
+ if(offset >= command_bytes){
+ break;
+ }
+
+ if(ident.fields.type == pitchbend){
+ ident.fields.control = 0;
+ val.normalised = (double)((frame[offset] << 7) | frame[offset - 1]) / 16384.0;
+ }
+ else{
+ ident.fields.control = frame[offset - 1];
+ val.normalised = (double) frame[offset] / 127.0;
+ }
+
+ //fix-up note off events
+ if(ident.fields.type == 0x80){
+ ident.fields.type = note;
+ val.normalised = 0;
+ }
+
+ offset++;
+ }
+
+ DBGPF("Decoded command type %02X channel %d control %d value %f",
+ ident.fields.type, ident.fields.channel, ident.fields.control, val.normalised);
+
+ if(cfg.detect){
+ if(ident.fields.type == pitchbend || ident.fields.type == aftertouch){
+ LOGPF("Incoming data on channel %s.ch%d.%s, value %f",
+ inst->name, ident.fields.channel,
+ rtpmidi_type_name(ident.fields.type), val.normalised);
+ }
+ else{
+ LOGPF("Incoming data on channel %s.ch%d.%s%d, value %f",
+ inst->name, ident.fields.channel,
+ rtpmidi_type_name(ident.fields.type),
+ ident.fields.control, val.normalised);
+ }
+ }
+
+ //find channel
+ chan = mm_channel(inst, ident.label, 0);
+ if(chan){
+ mm_channel_event(chan, val);
+ }
+
+ decode_time = 1;
+ } while(offset < command_bytes);
+
+ return 0;
+}
+
static int rtpmidi_handle_data(instance* inst){
- size_t u;
rtpmidi_instance_data* data = (rtpmidi_instance_data*) inst->impl;
uint8_t frame[RTPMIDI_PACKET_BUFFER] = "";
struct sockaddr_storage sock_addr;
socklen_t sock_len = sizeof(sock_addr);
rtpmidi_header* rtp_header = (rtpmidi_header*) frame;
ssize_t bytes_recv = recvfrom(data->fd, frame, sizeof(frame), 0, (struct sockaddr*) &sock_addr, &sock_len);
+ size_t u;
//TODO receive until EAGAIN
if(bytes_recv < 0){
@@ -645,7 +792,11 @@ static int rtpmidi_handle_data(instance* inst){
return 0;
}
- //TODO parse data
+ //parse data
+ if(rtpmidi_parse(inst, frame + sizeof(rtpmidi_header), bytes_recv - sizeof(rtpmidi_header))){
+ //returning errors here fails the core loop, so just return 0 to have some logging
+ return 0;
+ }
//try to learn peers
if(data->learn_peers){