port to linux, stage 1

backend/alsa_wrapper/alsa_wrapper.c

@@ -0,0 +1,64 @@
+#include <alsa/asoundlib.h>
+#include "alsa_wrapper.h"
+
+int new_client(char* client_name) {
+    int status;
+    status = snd_seq_open(&seq_handle, "hw", SND_SEQ_OPEN_OUTPUT, 0);
+    if (status < 0) {
+        return 1<<16|status;
+    }
+
+    seq_client = snd_seq_client_id(seq_handle);
+    if (seq_client < 0) {
+        return 2<<16|status;
+    }
+
+    status = snd_seq_client_name(seq_handle, client_name);
+    if (status < 0) {
+        return 3<<16|status;
+    }
+
+    // Success
+    return 0;
+}
+
+int new_port(char* port_name) {
+    seq_port = snd_seq_create_simple_port(seq_handle, portname, 
+                SND_SEQ_PORT_CAP_READ|SND_SEQ_PORT_CAP_SUBS_READ,
+                SND_SEQ_PORT_TYPE_MIDI_GENERIC|SND_SEQ_PORT_TYPE_APPLICATION);
+    if (seq_port < 0) {
+        return seq_port;
+    }
+
+    // Success
+    return 0;
+}
+
+int send_data(char* data, int length) {
+    int status;
+    snd_midi_event_t* midiParser;
+
+    status = snd_midi_event_new(length, &midiParser);
+    if (status < 0) {
+        return 1<<16|status;
+    }
+
+    snd_seq_event_t* ev;
+    snd_seq_ev_clear(ev);
+
+    status = snd_midi_event_encode(midiParser, data, length, ev);
+    if (status < 0) {
+        return 2<<16|status;
+    }
+
+    snd_seq_ev_set_direct(ev);
+    snd_seq_ev_set_source(ev, seq_port);
+    snd_seq_ev_set_dest(ev, SND_SEQ_ADDRESS_SUBSCRIBERS, 0);    
+
+    status = snd_seq_event_output_direct(seq_handle, ev);
+    if (status < 0) {
+        return 3<<16|status;
+    }
+
+    return 0;
+}

backend/alsa_wrapper/alsa_wrapper.h

@@ -0,0 +1,12 @@
+#ifndef ARREMI_ALSA_WRAPPER_H
+#define ARREMI_ALSA_WRAPPER_H
+
+#include <alsa/asoundlib.h>
+
+static snd_seq_t *seq_handle;
+int seq_client, seq_port;
+
+int new_client(char*);
+int new_port(char*);
+int send_data(char*, int);
+#endif