From e5bff67c1394bd0f9eb02a2dd6a33785e07dede3 Mon Sep 17 00:00:00 2001
From: Chris Cannam <cannam@all-day-breakfast.com>
Date: Thu, 7 Mar 2024 11:50:39 +0000
Subject: [PATCH] Replace platform-dependent barriers with c++11 std

---
 src/common/RingBuffer.h |  9 ++++++---
 src/common/sysutils.cpp | 25 -------------------------
 src/common/sysutils.h   | 38 --------------------------------------
 3 files changed, 6 insertions(+), 66 deletions(-)

diff --git a/src/common/RingBuffer.h b/src/common/RingBuffer.h
index 3fb0c836..580422c3 100644
--- a/src/common/RingBuffer.h
+++ b/src/common/RingBuffer.h
@@ -238,7 +238,8 @@ RingBuffer<T>::resized(int newSize) const
 {
     RingBuffer<T> *newBuffer = new RingBuffer<T>(newSize);
     
-    MBARRIER();
+    std::atomic_thread_fence(std::memory_order_seq_cst);
+    
     int w = m_writer;
     int r = m_reader;
 
@@ -464,7 +465,8 @@ RingBuffer<T>::write(const S *const R__ source, int n)
     w += n;
     while (w >= m_size) w -= m_size;
 
-    MBARRIER();
+    std::atomic_thread_fence(std::memory_order_seq_cst);
+    
     m_writer = w;
 
     return n;
@@ -498,7 +500,8 @@ RingBuffer<T>::zero(int n)
     w += n;
     while (w >= m_size) w -= m_size;
 
-    MBARRIER();
+    std::atomic_thread_fence(std::memory_order_seq_cst);
+    
     m_writer = w;
 
     return n;
diff --git a/src/common/sysutils.cpp b/src/common/sysutils.cpp
index c5779b6b..4321ea15 100644
--- a/src/common/sysutils.cpp
+++ b/src/common/sysutils.cpp
@@ -166,31 +166,6 @@ void gettimeofday(struct timeval *tv, void * /* tz */)
 
 #endif
 
-#ifdef _WIN32
-void system_memorybarrier()
-{
-#ifdef _MSC_VER
-    MemoryBarrier();
-#else /* (mingw) */
-    LONG Barrier = 0;
-    __asm__ __volatile__("xchgl %%eax,%0 "
-                         : "=r" (Barrier));
-#endif
-}
-#else /* !_WIN32 */
-#if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)
-// Not required
-#else
-#include <pthread.h>
-void system_memorybarrier()
-{
-    pthread_mutex_t dummy = PTHREAD_MUTEX_INITIALIZER;
-    pthread_mutex_lock(&dummy);
-    pthread_mutex_unlock(&dummy);
-}
-#endif
-#endif
-
 }
 
 
diff --git a/src/common/sysutils.h b/src/common/sysutils.h
index 53a771e6..37edb989 100644
--- a/src/common/sysutils.h
+++ b/src/common/sysutils.h
@@ -117,43 +117,5 @@ void gettimeofday(struct timeval *p, void *tz);
 
 } // end namespace
 
-// The following should be functions in the RubberBand namespace, really
-
-#ifdef _WIN32
-
-namespace RubberBand {
-extern void system_memorybarrier();
-}
-#define MBARRIER() RubberBand::system_memorybarrier()
-
-#else // !_WIN32
-
-#include <stdio.h>
-
-#ifdef __APPLE__
-#  if defined __MAC_10_12
-#    define MBARRIER() __sync_synchronize()
-#  else
-#    include <libkern/OSAtomic.h>
-#    define MBARRIER() OSMemoryBarrier()
-#  endif
-#else
-#  if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)
-#    define MBARRIER() __sync_synchronize()
-#  else
-namespace RubberBand {
-extern void system_memorybarrier();
-}
-#    define MBARRIER() ::RubberBand::system_memorybarrier()
-#  endif
-#endif
-
-#endif // !_WIN32
-
-#ifdef NO_THREADING
-#  undef MBARRIER
-#  define MBARRIER() 
-#endif // NO_THREADING
-
 #endif