Diff: cyclicalBUFFER.cpp

Revision:

0:4ccd12e1d789

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cyclicalBUFFER.cpp	Tue Jan 08 16:21:39 2019 +0000
@@ -0,0 +1,129 @@
+/*------------------------------------------------------------------------------
+Creator : Joel Pallent ; Jonathan Wheadon
+Date : 06/12/2018
+Module : ELEC351
+Project : ELEC351_GroupA
+Dependencies : "semaphore.hpp"
+Purpose : to control the flow of data to synchronise everything so that there is
+no problems with the transmit and retrival of data between threads
+
+------------------------------------------------------------------------------*/
+
+#include "cyclicalBUFFER.hpp" 
+
+//Producer
+void cyclical_Buffer::addDataToBuffer(mail_t Data)     
+{
+    //Is there space?
+    int32_t Nspaces = spaceAvailable.wait();
+             
+    //Ok, there is space - take the lock
+    bufferLock.lock();
+        
+    //Update buffer
+    newestIndex = (newestIndex+1) % BUFFERSIZE;  
+    buffer[newestIndex] = Data;               
+    //printf("Data added to buffer"); 
+    
+    //Release lock
+    bufferLock.unlock();
+    
+    //Signal that a sample has been added
+    samplesInBuffer.release();
+    NoOfStoredSamples += 1;
+    
+    if(NoOfStoredSamples == BUFFERSIZE){
+        BufferFull = true;
+    } else {
+        BufferFull = false;
+    }
+}
+
+// the function addDataToBufferOverride adds data to the buffer, if the buffer is full it overides the oldest stored data
+void cyclical_Buffer::addDataToBufferOverride(mail_t Data)     
+{
+    bufferLock.lock();
+    
+    if( BufferFull == true ){
+        oldestIndex = (oldestIndex+1) % BUFFERSIZE;
+        Data = buffer[oldestIndex];
+        NoOfStoredSamples -= 1;
+        BufferFull = false;
+    }
+        
+    //Update buffer
+    newestIndex = (newestIndex+1) % BUFFERSIZE;  
+    buffer[newestIndex] = Data;               
+    //printf("Data added to buffer"); 
+    
+    //Release lock
+    bufferLock.unlock();
+    
+    //Signal that a sample has been added
+    NoOfStoredSamples += 1;
+    
+    if(NoOfStoredSamples == BUFFERSIZE){
+        BufferFull = true;
+    } else {
+        BufferFull = false;
+    }
+}
+
+//Consumer
+mail_t cyclical_Buffer::takeDataFromBuffer(void)
+{    
+    //Are thre any samples in the buffer
+    int32_t Nsamples = samplesInBuffer.wait();
+        
+    //Ok, there are samples - take the lock
+    bufferLock.lock();   
+    
+    mail_t Data;
+    
+    //Update buffer - remove oldest
+    oldestIndex = (oldestIndex+1) % BUFFERSIZE;
+    Data = buffer[oldestIndex];    
+    
+    //Release lock
+    bufferLock.unlock();
+    
+    //Signal there is space in the buffer
+    spaceAvailable.release();                            // change the space available soother things rying to acces the buffer can see there is space
+    NoOfStoredSamples -= 1;
+    
+    BufferFull = false;
+       
+    //return a copy of the result
+    return Data;                                     // returing the input data out in new structure.
+}
+
+// Returns data stored in the Nth place of the buffer
+mail_t cyclical_Buffer::ReadNfromBuffer(UINT_32 N)
+{
+    bufferLock.lock();
+    
+    // If N exceeds the stored samples
+    if((NoOfStoredSamples == 0) || (N > (NoOfStoredSamples - 1))){
+        
+        mail_t voided = {NULL,NULL,NULL,NULL};
+        
+        bufferLock.unlock();
+
+        return voided;
+        
+    } else {
+        
+        UINT_32 idx = (newestIndex - N + 1) % BUFFERSIZE;   
+        
+        mail_t Data;
+        
+        Data = buffer[idx];    
+        
+        //Release lock
+        bufferLock.unlock();
+            
+        //return a copy of the result
+        return Data;
+    }
+}
+