Fix issue with potential audio block leak

If there aren't enough audio blocks to allocate, the previous code returned without releasing the ones it had allocated, leaving them unavailable for re-use. This would almost certainly rapidly break the entire audio system.

Author: h4yn0nnym0u5e

src/playresmp.h

@@ -99,11 +99,12 @@ class AudioPlayResmp : public AudioStream
 
         void update()
         {
+			bool gotBlocks = true;
             int _numChannels = reader->getNumChannels();
             if (_numChannels == -1)
                 return;
 
-            unsigned int i, n;
+            unsigned int n;
             audio_block_t *blocks[_numChannels];
             int16_t *data[_numChannels];
             // only update if we're playing
@@ -112,28 +113,40 @@ class AudioPlayResmp : public AudioStream
             // allocate the audio blocks to transmit
             for (int i=0; i < _numChannels; i++) {
                 blocks[i] = allocate();
-                if (blocks[i] == nullptr) return;
-                data[i] = blocks[i]->data;
+                if (blocks[i] == nullptr) 
+					gotBlocks = false;
+				else
+					data[i] = blocks[i]->data;
             }
 
-            if (reader->available()) {
-                // we can read more data from the file...
-                n = reader->read((void**)data, AUDIO_BLOCK_SAMPLES);
-                for (int channel=0; channel < _numChannels; channel++) {
-                    memset( &blocks[channel]->data[n], 0, (AUDIO_BLOCK_SAMPLES - n) * 2);
-                    transmit(blocks[channel], channel);
-                }
-
-                if(_numChannels == 1) {
-                    transmit(blocks[0], 1);
-                }
-            } else {
-                reader->close();
-            }
-            for (int channel=0; channel < _numChannels; channel++) {
-                release(blocks[channel]);
+			if (gotBlocks) // enough blocks, do the transmit
+			{
+				if (reader->available()) {
+					// we can read more data from the file...
+					n = reader->read((void**)data, AUDIO_BLOCK_SAMPLES);
+					for (int channel=0; channel < _numChannels; channel++) {
+						memset( &blocks[channel]->data[n], 0, (AUDIO_BLOCK_SAMPLES - n) * 2);
+						transmit(blocks[channel], channel);
+					}
+
+					if(_numChannels == 1) {
+						transmit(blocks[0], 1);
+					}
+
+				} else {
+					reader->close();
+				}
+			}
+			
+			// release all allocated blocks, even if there
+			// weren't enough and we couldn't transmit
+            for (int channel=0; channel < _numChannels; channel++) 
+			{
+				if (nullptr != blocks[channel]) // only release if allocated!
+					release(blocks[channel]);
             }
         }
+		
         uint32_t positionMillis()
         {
             return reader->positionMillis();