dev95 - multiple songs in a single file (READ)

experimental feature! proceed with caution.
if you experience song corruption or crashes, report issue immediately!

files with multiple songs will be readable in older versions of Furnace,
but only the first song will be read in those versions.

issue #199

src/engine/engine.h

@@ -45,8 +45,8 @@
 #define BUSY_BEGIN_SOFT softLocked=true; isBusy.lock();
 #define BUSY_END isBusy.unlock(); softLocked=false;
 
-#define DIV_VERSION "dev94"
-#define DIV_ENGINE_VERSION 94
+#define DIV_VERSION "dev95"
+#define DIV_ENGINE_VERSION 95
 
 // for imports
 #define DIV_VERSION_MOD 0xff01
@@ -304,6 +304,7 @@ class DivEngine {
   bool hasLoadedSomething;
   int softLockCount;
   int subticks, ticks, curRow, curOrder, remainingLoops, nextSpeed;
+  size_t curSubSongIndex;
   double divider;
   int cycles;
   double clockDrift;
@@ -411,8 +412,14 @@ class DivEngine {
   void swapChannels(int src, int dest);
   void stompChannel(int ch);
 
+  // change song (UNSAFE)
+  void changeSong(size_t songIndex);
+
   public:
     DivSong song;
+    DivOrders* curOrders;
+    DivChannelData* curPat;
+    DivSubSong* curSubSong;
     DivInstrument* tempIns;
     DivSystem sysOfChan[DIV_MAX_CHANS];
     int dispatchOfChan[DIV_MAX_CHANS];
@@ -603,6 +610,9 @@ class DivEngine {
     // get current row
     int getRow();
 
+    // get current subsong
+    size_t getCurrentSubSong();
+
     // get speed 1
     unsigned char getSpeed1();
 
@@ -799,6 +809,15 @@ class DivEngine {
     // public swap channels
     void swapChannelsP(int src, int dest);
 
+    // public change song
+    void changeSongP(size_t index);
+
+    // add subsong
+    int addSubSong();
+
+    // remove subsong
+    bool removeSubSong(int index);
+
     // change system
     void changeSystem(int index, DivSystem which, bool preserveOrder=true);
 
@@ -900,6 +919,7 @@ class DivEngine {
       curOrder(0),
       remainingLoops(-1),
       nextSpeed(3),
+      curSubSongIndex(0),
       divider(60),
       cycles(0),
       clockDrift(0),
@@ -935,6 +955,8 @@ class DivEngine {
       metroAmp(0.0f),
       metroVol(1.0f),
       totalProcessed(0),
+      curOrders(NULL),
+      curPat(NULL),
       tempIns(NULL),
       oscBuf{NULL,NULL},
       oscSize(1),
@@ -959,6 +981,8 @@ class DivEngine {
         sysFileMapFur[i]=DIV_SYSTEM_NULL;
         sysFileMapDMF[i]=DIV_SYSTEM_NULL;
       }
+
+      changeSong(0);
     }
 };
 #endif