Timeline: Don't die if punch-in frame is before first block of recorded audio.

timeline/src/Engine/Record_DS.C

@@ -99,8 +99,8 @@ Record_DS::disk_thread ( void )
     bool punching_out = false;
     bool punched_in = false;
 
-    nframes_t bS = 0;
+    nframes_t bS = 0;                                           /* block start */
-    nframes_t bE = 0;
+    nframes_t bE = 0;                                           /* block end */
 
 again:
 
@@ -109,8 +109,8 @@ again:
     punched_in = false;
     punching_out = false;
 
-    nframes_t pS = _frame;
+    nframes_t pS = _frame;                                      /* punch start */
-    nframes_t pE = _stop_frame;
+    nframes_t pE = _stop_frame;                                 /* punch end */
 
     if ( punching_in )
     {
@@ -148,6 +148,22 @@ again:
 
         bE = _first_frame + frames_read;
         
+        if ( ! punched_in && bS > pS )
+        {
+            /* we're supposed to be punching in but don't have data
+               until a later frame... write null data instead.  FIXME:
+               it would probably be better to just have the record
+               threads running all the time so that there would always
+               have some actual data to write here */
+            sample_t  nbuf[bS - pS];
+            memset(nbuf,0,bS - pS);
+            write_block(nbuf, pS - pS);
+            write_block(buf,frames_to_read);
+            punched_in = true;
+            punching_in = false;
+        }
+        else
+        {
             punching_in = ! punched_in && bE > pS;
             punching_out = punched_in && pE < bE;
 
@@ -158,9 +174,11 @@ again:
 
                 break;
             }
-        else
+            else if ( punching_in )
-        if ( punching_in )
             {
+                assert( pS >= bS );
+                assert( bE >= pS );
+
                 write_block( buf + ((pS - bS) * channels()),
                              bE - pS );
 
@@ -172,6 +190,7 @@ again:
                 write_block( buf, bE - bS );
             }
         }
+    }
 
 //    DMESSAGE( "capture thread terminating" );