Threading crash fixes, reusable IQ buffer queue

src/demod/DemodDefs.h

@@ -5,6 +5,7 @@
 #include "liquid/liquid.h"
 
 #include <atomic>
+#include <mutex>
 
 enum DemodulatorType {
 	DEMOD_TYPE_NULL,
@@ -60,6 +61,7 @@ public:
 	unsigned int frequency;
 	unsigned int bandwidth;
 	std::vector<signed char> data;
+    mutable std::mutex m_mutex;
 
 	DemodulatorThreadIQData() :
 			frequency(0), bandwidth(0), refCount(0) {

src/demod/DemodulatorPreThread.cpp

@@ -157,6 +157,7 @@ void DemodulatorPreThread::threadMain() {
             continue;
         }
 
+        std::lock_guard < std::mutex > lock(inp->m_mutex);
         std::vector<signed char> *data = &inp->data;
         if (data->size()) {
             int bufSize = data->size() / 2;
@@ -173,6 +174,8 @@ void DemodulatorPreThread::threadMain() {
                 in_buf[i].imag = (float) (*data)[i * 2 + 1] / 127.0f;
             }
 
+            inp->decRefCount();
+
             if (shift_freq != 0) {
                 if (shift_freq < 0) {
                     nco_crcf_mix_block_up(nco_shift, in_buf, out_buf, bufSize);
@@ -195,10 +198,8 @@ void DemodulatorPreThread::threadMain() {
             resamp->resampler = resampler;
 
             postInputQueue->push(resamp);
+        } else {
             inp->decRefCount();
-            if (inp->getRefCount()<=0) {
-                delete inp;
-            }
         }
 
         if (!workerResults->empty()) {