examples/ofx/Bitalino_rapidmix/src/RingBuffer.hpp

+/*
+ * RingBuffer.hpp
+ */
+
+#ifndef RINGBUFFER_HPP
+#define RINGBUFFER_HPP
+
+#include <iostream>
+#include <atomic>
+#include <string>
+#include <unistd.h>
+#include <string.h> // memcpy
+#include <cstring>
+
+template <class T>
+class RingBuffer
+{
+public:
+    RingBuffer();
+    RingBuffer(unsigned long size);
+    ~RingBuffer();
+    void setup(unsigned long size);
+    
+    unsigned long push(const T* data, unsigned long n);
+    unsigned long pop(T* data, unsigned long n);
+    unsigned long getWithoutPop(T* data, unsigned long n);
+    unsigned long items_available_for_write() const;
+    unsigned long items_available_for_read() const;
+    bool isLockFree() const;
+    void pushMayBlock(bool block);
+    void popMayBlock(bool block);
+    void setBlockingNap(unsigned long blockingNap);
+    void setSize(unsigned long size);
+    void reset();
+    
+private:
+    unsigned long array_size;
+    T* buffer = nullptr;
+    long type_size; // also depends on #channels
+
+    std::atomic<unsigned long> tail_index; // write pointer
+    std::atomic<unsigned long> head_index; // read pointer
+
+    bool blockingPush;
+    bool blockingPop;
+    useconds_t blockingNap = 500;
+}; // RingBuffer{}
+
+template <class T>
+RingBuffer<T>::RingBuffer()
+{
+    tail_index = 0;
+    head_index = 0;
+    
+    blockingPush = false;
+    blockingPop = false;
+} // RingBuffer()
+
+template <class T>
+RingBuffer<T>::RingBuffer(unsigned long array_size)
+{
+    tail_index = 0;
+    head_index = 0;
+    
+    blockingPush = false;
+    blockingPop = false;
+    
+    setup(array_size);
+} // RingBuffer()
+
+template <class T>
+RingBuffer<T>::~RingBuffer()
+{
+    if (buffer)
+        delete [] buffer;
+} // ~RingBuffer()
+
+template <class T>
+void RingBuffer<T>::setup(unsigned long array_size)
+{
+    if (buffer)
+        delete [] buffer;
+    
+    this->array_size = array_size;
+    buffer = new T [array_size](); // allocate storage
+    type_size = sizeof(T);
+}
+
+template <class T>
+unsigned long RingBuffer<T>::items_available_for_write() const
+{
+    long pointerspace = head_index.load()-tail_index.load(); // signed
+    
+    if(pointerspace > 0) return pointerspace; // NB: > 0 so NOT including 0
+    else return pointerspace + array_size;
+} // items_available_for_write()
+
+template <class T>
+unsigned long RingBuffer<T>::items_available_for_read() const
+{
+    long pointerspace = tail_index.load() - head_index.load(); // signed
+    
+    if(pointerspace >= 0) return pointerspace; // NB: >= 0 so including 0
+    else return pointerspace + array_size;
+} // items_available_for_read()
+
+template <class T>
+void RingBuffer<T>::pushMayBlock(bool block)
+{
+    this->blockingPush = block;
+} // pushMayBlock()
+
+template <class T>
+void RingBuffer<T>::popMayBlock(bool block)
+{
+    this->blockingPop = block;
+} // popMayBlock()
+
+template <class T>
+void RingBuffer<T>::setBlockingNap(unsigned long blockingNap)
+{
+    this->blockingNap = blockingNap;
+} // setBlockingNap()
+
+
+/*
+ * Try to write as many items as possible and return the number actually written
+ */
+template <class T>
+unsigned long RingBuffer<T>::push(const T* data, unsigned long n)
+{
+    unsigned long space = array_size, n_to_write, memory_to_write, first_chunk, second_chunk, current_tail;
+    
+    //space = items_available_for_write();
+    if(blockingPush)
+    {
+        while((space = items_available_for_write()) < n)
+        { // blocking
+            usleep(blockingNap);
+        } // while, possibly use a system level sleep operation with CVAR?
+    } // if
+    
+    n_to_write = (n <= space) ? n : space; // limit
+    
+    current_tail = tail_index.load();
+    if(current_tail + n_to_write <= array_size)
+    { // chunk fits without wrapping
+        memory_to_write = n_to_write * type_size;
+        memcpy(buffer+current_tail, data, memory_to_write);
+        tail_index.store(current_tail + n_to_write);
+    }
+    else { // chunk has to wrap
+        first_chunk = array_size - current_tail;
+        memory_to_write = first_chunk * type_size;
+        memcpy(buffer + current_tail, data, memory_to_write);
+        
+        second_chunk = n_to_write - first_chunk;
+        memory_to_write = second_chunk * type_size;
+        memcpy(buffer, data + first_chunk, memory_to_write);
+        tail_index.store(second_chunk);
+    }
+    
+    return n_to_write;
+} // push()
+
+
+/*
+ * Try to read as many items as possible and return the number actually read
+ */
+template <class T>
+unsigned long RingBuffer<T>::pop(T* data, unsigned long n)
+{
+    unsigned long space = array_size, n_to_read, memory_to_read, first_chunk, second_chunk, current_head;
+    
+    //space = items_available_for_read(); //if checking outside of thread, not necessary?
+    if(blockingPop)
+    {
+        while((space = items_available_for_read()) < n)
+        { // blocking
+            usleep(blockingNap);
+        } // while
+    } // if
+    
+    if(space == 0)
+        return 0;
+    
+    n_to_read = (n <= space) ? n : space; // limit
+    
+    current_head = head_index.load();
+    if(current_head + n_to_read <= array_size)
+    { // no wrapping necessary
+        memory_to_read = n_to_read * type_size;
+        memcpy(data, buffer + current_head, memory_to_read);
+        head_index.store(current_head + n_to_read);
+    }
+    else { // read has to wrap
+        first_chunk = array_size - current_head;
+        memory_to_read = first_chunk * type_size;
+        memcpy(data, buffer + current_head, memory_to_read);
+        
+        second_chunk = n_to_read - first_chunk;
+        memory_to_read = second_chunk * type_size;
+        memcpy(data + first_chunk, buffer, memory_to_read);
+        head_index.store(second_chunk);
+
+    }
+    return n_to_read;
+} // pop()
+
+/*
+ * Try to read as many items as possible and return the number actually read
+ */
+template <class T>
+unsigned long RingBuffer<T>::getWithoutPop(T* data, unsigned long n)
+{
+    unsigned long space = array_size, n_to_read, memory_to_read, first_chunk, second_chunk, current_head;
+    
+    //space = items_available_for_read(); //if checking outside of thread, not necessary?
+    if(blockingPop)
+    {
+        while((space = items_available_for_read()) < n)
+        { // blocking
+            usleep(blockingNap);
+        } // while
+    } // if
+    
+    if(space == 0)
+        return 0;
+    
+    n_to_read = (n <= space) ? n : space; // limit
+    
+    current_head = head_index.load();
+    if(current_head + n_to_read <= array_size)
+    { // no wrapping necessary
+        memory_to_read = n_to_read * type_size;
+        memcpy(data, buffer + current_head, memory_to_read);
+        //head_index.store(current_head + n_to_read);
+    }
+    else { // read has to wrap
+        first_chunk = array_size - current_head;
+        memory_to_read = first_chunk * type_size;
+        memcpy(data, buffer + current_head, memory_to_read);
+        
+        second_chunk = n_to_read - first_chunk;
+        memory_to_read = second_chunk * type_size;
+        memcpy(data + first_chunk, buffer, memory_to_read);
+        //head_index.store(second_chunk);
+        
+    }
+    return n_to_read;
+} // getWithoutPop()
+
+template <class T>
+bool RingBuffer<T>::isLockFree() const
+{
+    return (tail_index.is_lock_free() && head_index.is_lock_free());
+} // isLockFree()
+
+
+template <class T>
+void RingBuffer<T>::setSize(unsigned long size)
+{
+    if (buffer)
+        delete [] buffer;
+    
+    this->array_size = array_size;
+    buffer = new T [array_size](); // allocate storage
+    type_size = sizeof(T);
+    tail_index.store(0);
+    head_index.store(0);
+}
+
+template <class T>
+void RingBuffer<T>::reset()
+{
+    tail_index.store(0);
+    head_index.store(0);
+} // isLockFree()
+
+#endif

examples/ofx/Bitalino_rapidmix/src/SigTools.cpp

+//
+//  SigTools.cpp
+//  
+//
+//  Created by James on 08/01/17.
+//
+//
+
+#include "SigTools.hpp"
+
+double MTOF ( unsigned char midi ) {
+    return pow( 2, static_cast< double >( midi-69 ) / 12.0 ) * 440.0;
+}
+
+double FTOM ( double freq ) {
+    return 12.0 * log2( freq / 440.0 ) + 69;
+}

examples/ofx/Bitalino_rapidmix/src/SigTools.hpp

+//
+//  SigTools.hpp
+//  
+//
+//  Created by James on 08/01/17.
+//
+//
+
+#ifndef SigTools_hpp
+#define SigTools_hpp
+
+#include <stdio.h>
+#include <math.h>
+
+double MTOF ( unsigned char midi );
+double FTOM ( double freq );
+
+#endif /* SigTools_hpp */

examples/ofx/Bitalino_rapidmix/src/Spinlock.hpp

+//
+//  Spinlock.h
+//  beladrum
+//
+//  Created by James on 11/05/17.
+//  Copyright © 2017 HKU. All rights reserved.
+//
+
+#ifndef Spinlock_h
+#define Spinlock_h
+
+#include <atomic>
+
+class Spinlock {
+    std::atomic_flag locked = ATOMIC_FLAG_INIT ;
+public:
+    void lock ( void ) {
+        while (locked.test_and_set(std::memory_order_acquire)) { ; }
+    }
+    void unlock ( void ) {
+        locked.clear(std::memory_order_release);
+    }
+};
+
+#endif /* Spinlock_h */

examples/ofx/Bitalino_rapidmix/src/main.cpp

+#include "ofApp.h"
+#include "ofAppGlutWindow.h"
+
+//========================================================================
+int main( ){
+    ofAppGlutWindow window;
+	ofSetupOpenGL( &window, 1024, 768, OF_WINDOW );			// <-------- setup the GL context
+
+	ofRunApp( new ofApp(  ) );
+
+}