Imported Upstream version 3.2.2

[debian/gnuradio] / gr-audio-osx / src / circular_buffer.h

diff --git a/gr-audio-osx/src/circular_buffer.h b/gr-audio-osx/src/circular_buffer.h
index 984182dd2b3f578b97933d9f91350ca7ba411bbc..fa451d607b728e2c64a92ef067720b1551351d39 100644 (file)
--- a/gr-audio-osx/src/circular_buffer.h
+++ b/gr-audio-osx/src/circular_buffer.h
@@ -28,6 +28,12 @@
 
 #define DO_DEBUG 0
 
+#if DO_DEBUG
+#define DEBUG(X) do{X} while(0);
+#else
+#define DEBUG(X) do{} while(0);
+#endif
+
 template <class T> class circular_buffer
 {
 private:
@@ -73,12 +79,10 @@ public:
     d_internal = NULL;
     d_readBlock = d_writeBlock = NULL;
     reset ();
-#if DO_DEBUG
-    fprintf (stderr, "c_b(): buf len (items) = %ld, "
-            "doWriteBlock = %s, doFullRead = %s\n", d_bufLen_I,
-            (d_doWriteBlock ? "true" : "false"),
-            (d_doFullRead ? "true" : "false"));
-#endif
+    DEBUG (fprintf (stderr, "c_b(): buf len (items) = %ld, "
+                   "doWriteBlock = %s, doFullRead = %s\n", d_bufLen_I,
+                   (d_doWriteBlock ? "true" : "false"),
+                   (d_doFullRead ? "true" : "false")));
   };
 
   ~circular_buffer () {
@@ -110,9 +114,16 @@ public:
     d_readNdx_I = d_writeNdx_I = d_n_avail_read_I = 0;
     d_n_avail_write_I = d_bufLen_I;
     delete_mutex_cond ();
+    // create a mutex to handle contention of shared resources;
+    // any routine needed access to shared resources uses lock()
+    // before doing anything, then unlock() when finished.
     d_internal = new mld_mutex ();
-    d_readBlock = new mld_condition ();
-    d_writeBlock = new mld_condition ();
+    // link the internal mutex to the read and write conditions;
+    // when wait() is called, the internal mutex will automatically
+    // be unlock()'ed.  Upon return (from a signal() to the condition),
+    // the internal mutex will be lock()'ed.
+    d_readBlock = new mld_condition (d_internal);
+    d_writeBlock = new mld_condition (d_internal);
   };
 
 /*
@@ -137,11 +148,9 @@ public:
  */
 
   int enqueue (T* buf, UInt32 bufLen_I) {
-#if DO_DEBUG
-    fprintf (stderr, "enqueue: buf = %X, bufLen = %ld, #av_wr = %ld, "
-            "#av_rd = %ld.\n", (unsigned int)buf, bufLen_I,
-            d_n_avail_write_I, d_n_avail_read_I);
-#endif
+    DEBUG (fprintf (stderr, "enqueue: buf = %X, bufLen = %ld, #av_wr = %ld, "
+                   "#av_rd = %ld.\n", (unsigned int)buf, bufLen_I,
+                   d_n_avail_write_I, d_n_avail_read_I));
     if (bufLen_I > d_bufLen_I) {
       fprintf (stderr, "cannot add buffer longer (%ld"
               ") than instantiated length (%ld"
@@ -159,33 +168,27 @@ public:
       d_internal->unlock ();
       return (2);
     }
+    // set the return value to 1: success; change if needed
+    int retval = 1;
     if (bufLen_I > d_n_avail_write_I) {
       if (d_doWriteBlock) {
        while (bufLen_I > d_n_avail_write_I) {
-#if DO_DEBUG
-         fprintf (stderr, "enqueue: #len > #a, waiting.\n");
-#endif
-         d_internal->unlock ();
+         DEBUG (fprintf (stderr, "enqueue: #len > #a, waiting.\n"));
+         // wait will automatically unlock() the internal mutex
          d_writeBlock->wait ();
-         d_internal->lock ();
+         // and lock() it here.
          if (d_doAbort) {
            d_internal->unlock ();
-#if DO_DEBUG
-           fprintf (stderr, "enqueue: #len > #a, aborting.\n");
-#endif
+           DEBUG (fprintf (stderr, "enqueue: #len > #a, aborting.\n"));
            return (2);
          }
-#if DO_DEBUG
-         fprintf (stderr, "enqueue: #len > #a, done waiting.\n");
-#endif
+         DEBUG (fprintf (stderr, "enqueue: #len > #a, done waiting.\n"));
        }
       } else {
        d_n_avail_read_I = d_bufLen_I - bufLen_I;
        d_n_avail_write_I = bufLen_I;
-#if DO_DEBUG
-       fprintf (stderr, "circular_buffer::enqueue: overflow\n");
-#endif
-       return (-1);
+       DEBUG (fprintf (stderr, "circular_buffer::enqueue: overflow\n"));
+       retval = -1;
       }
     }
     UInt32 n_now_I = d_bufLen_I - d_writeNdx_I, n_start_I = 0;
@@ -203,7 +206,7 @@ public:
     d_n_avail_write_I -= bufLen_I;
     d_readBlock->signal ();
     d_internal->unlock ();
-    return (1);
+    return (retval);
   };
 
 /*
@@ -228,11 +231,9 @@ public:
  */
 
   int dequeue (T* buf, UInt32* bufLen_I) {
-#if DO_DEBUG
-    fprintf (stderr, "dequeue: buf = %X, *bufLen = %ld, #av_wr = %ld, "
-            "#av_rd = %ld.\n", (unsigned int)buf, *bufLen_I,
-            d_n_avail_write_I, d_n_avail_read_I);
-#endif
+    DEBUG (fprintf (stderr, "dequeue: buf = %X, *bufLen = %ld, #av_wr = %ld, "
+                   "#av_rd = %ld.\n", (unsigned int)buf, *bufLen_I,
+                   d_n_avail_write_I, d_n_avail_read_I));
     if (!bufLen_I)
       throw std::runtime_error ("circular_buffer::dequeue(): "
                                "input bufLen pointer is NULL.\n");
@@ -256,41 +257,29 @@ public:
     }
     if (d_doFullRead) {
       while (d_n_avail_read_I < l_bufLen_I) {
-#if DO_DEBUG
-       fprintf (stderr, "dequeue: #a < #len, waiting.\n");
-#endif
-       d_internal->unlock ();
+       DEBUG (fprintf (stderr, "dequeue: #a < #len, waiting.\n"));
+       // wait will automatically unlock() the internal mutex
        d_readBlock->wait ();
-       d_internal->lock ();
+       // and lock() it here.
        if (d_doAbort) {
          d_internal->unlock ();
-#if DO_DEBUG
-         fprintf (stderr, "dequeue: #a < #len, aborting.\n");
-#endif
+         DEBUG (fprintf (stderr, "dequeue: #a < #len, aborting.\n"));
          return (2);
        }
-#if DO_DEBUG
-       fprintf (stderr, "dequeue: #a < #len, done waiting.\n");
-#endif
+       DEBUG (fprintf (stderr, "dequeue: #a < #len, done waiting.\n"));
      }
     } else {
       while (d_n_avail_read_I == 0) {
-#if DO_DEBUG
-       fprintf (stderr, "dequeue: #a == 0, waiting.\n");
-#endif
-       d_internal->unlock ();
+       DEBUG (fprintf (stderr, "dequeue: #a == 0, waiting.\n"));
+       // wait will automatically unlock() the internal mutex
        d_readBlock->wait ();
-       d_internal->lock ();
+       // and lock() it here.
        if (d_doAbort) {
          d_internal->unlock ();
-#if DO_DEBUG
-         fprintf (stderr, "dequeue: #a == 0, aborting.\n");
-#endif
+         DEBUG (fprintf (stderr, "dequeue: #a == 0, aborting.\n"));
          return (2);
        }
-#if DO_DEBUG
-       fprintf (stderr, "dequeue: #a == 0, done waiting.\n");
-#endif
+       DEBUG (fprintf (stderr, "dequeue: #a == 0, done waiting.\n"));
       }
     }
     if (l_bufLen_I > d_n_avail_read_I)