From ba1b63a4352c3c6cab3ef716fded14fe3c11c064 Mon Sep 17 00:00:00 2001
From: Paul Licameli <paul.licameli@audacityteam.org>
Date: Wed, 22 Jun 2016 15:39:06 -0400
Subject: [PATCH] Bug1223 again: redo the fix exactly as Roger Dannenberg wants
 it

---
 lib-src/libnyquist/nyquist/nyqsrc/sound.c | 57 +++++++++++------------
 1 file changed, 26 insertions(+), 31 deletions(-)

diff --git a/lib-src/libnyquist/nyquist/nyqsrc/sound.c b/lib-src/libnyquist/nyquist/nyqsrc/sound.c
index ae498f41a..84803fdc3 100644
--- a/lib-src/libnyquist/nyquist/nyqsrc/sound.c
+++ b/lib-src/libnyquist/nyquist/nyqsrc/sound.c
@@ -515,43 +515,38 @@ void snd_list_terminate(snd_list)
 
 void snd_list_unref(snd_list_type list)
 {
-    void (*freefunc)();
-
    if (list == NULL) {
       nyquist_printf("why did snd_list_unref get %p?\n", list);
       return;
    }
 
-    while (! (list == NULL || list == zero_snd_list) ) {
-       list->refcnt--;
-   /*    nyquist_printf("snd_list_unref "); print_snd_list_type(list); stdputstr("\n"); */
-       if (list->refcnt == 0) {
-           snd_list_type next;
-           if (list->block && list->block != zero_block) {
-               /* there is a next snd_list */
-               next = list->u.next;
-   /*          stdputstr("["); */
-               sample_block_unref(list->block);
-   /*          stdputstr("]"); */
-           }
-           else if (list->block == NULL) { /* the next thing is the susp */
-               /* free suspension structure */
-               /* nyquist_printf("freeing susp@%p\n", list->u.susp); */
-               freefunc = list->u.susp->free;
-               (*freefunc)(list->u.susp);
-               next = NULL;
-           }
-           /* nyquist_printf("freeing snd_list@%p\n", list); */
-           //DBY
-           if (list == list_watch) printf("freeing watched snd_list %p\n", list);
-           //DBY
-           ffree_snd_list(list, "snd_list_unref");
+   while (list && (list != zero_snd_list)) {
+      snd_list_type next;
 
-           list = next;
-       }
-       else
-          break;
-    }
+      list->refcnt--;
+      if (list->refcnt != 0) {
+         break; // the rest of the list is shared, nothing more to free
+      }
+
+      // list nodes either point to a block of samples or this is the
+      // last list node (list->block == NULL) which points to a suspension
+      // lists can also terminate at the zero_block, which is an infinite
+      //     shared list (zero_block->block == zero_block) of zero samples
+      if (list->block && list->block != zero_block) {
+         /* there is a next snd_list */
+         next = list->u.next;
+         sample_block_unref(list->block);
+      } else if (list->block == NULL) { /* the next thing is the susp */
+         /* free suspension structure */
+         /* nyquist_printf("freeing susp@%p\n", list->u.susp); */
+         (*(list->u.susp->free))(list->u.susp);
+         next = NULL;
+      }
+      /* if (list == list_watch)
+       printf("freeing watched snd_list %p\n", list); */
+      ffree_snd_list(list, "snd_list_unref");
+      list = next;
+   }
 }