From ae3d4599606483a7cc0b1f01ba848a7390db4207 Mon Sep 17 00:00:00 2001
From: Anthony Pesch <inolen@gmail.com>
Date: Sun, 11 Dec 2016 13:25:09 -0800
Subject: [PATCH] removed failed atomic shim, compile ringbuf as c++

---
 CMakeLists.txt                     |  5 +---
 src/core/{ringbuf.c => ringbuf.cc} | 26 ++++++++-----------
 src/sys/atomic.h                   | 40 ------------------------------
 3 files changed, 12 insertions(+), 59 deletions(-)
 rename src/core/{ringbuf.c => ringbuf.cc} (65%)
 delete mode 100644 src/sys/atomic.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7fb8e2ab..2db42275 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -158,7 +158,7 @@ set(REDREAM_SOURCES
   src/core/mm_heap.c
   src/core/option.c
   src/core/profiler.cc
-  src/core/ringbuf.c
+  src/core/ringbuf.cc
   src/core/rb_tree.c
   src/core/string.c
   src/emu/emulator.c
@@ -270,9 +270,6 @@ elseif(COMPILER_MSVC)
   list(APPEND REDREAM_FLAGS -D_SCL_SECURE_NO_WARNINGS -D_CRT_SECURE_NO_WARNINGS -DWIN32_LEAN_AND_MEAN -DNOMINMAX /GR- /W3 /WX /wd4100 /wd4127 /wd4505 /wd4512 /wd4800 /wd4351)
 
   list(APPEND REDREAM_LIBS userenv ws2_32)
-
-  # until msvc supports stdatomic.h, compile code using atomics as C++
-  set_source_files_properties(src/core/ringbuf.c PROPERTIES LANGUAGE CXX)
 endif()
 
 add_executable(redream ${REDREAM_SOURCES})
diff --git a/src/core/ringbuf.c b/src/core/ringbuf.cc
similarity index 65%
rename from src/core/ringbuf.c
rename to src/core/ringbuf.cc
index 522b965c..bdc279ac 100644
--- a/src/core/ringbuf.c
+++ b/src/core/ringbuf.cc
@@ -1,36 +1,32 @@
-/* this file is compiled as C++ under MSVC due to it not supporting stdatomic.h */
-#ifdef __cplusplus
+/* would be nice to convert this file to C once MSVC supports stdatomic.h */
+#include <atomic>
 extern "C" {
-#endif
 #include "core/ringbuf.h"
 #include "core/assert.h"
-#ifdef __cplusplus
 }
-#endif
-#include "sys/atomic.h"
 
 struct ringbuf {
   int capacity;
   uint8_t *data;
-  struct re_atomic_long read_offset;
-  struct re_atomic_long write_offset;
+  std::atomic<int64_t> read_offset;
+  std::atomic<int64_t> write_offset;
 };
 
 void ringbuf_advance_write_ptr(struct ringbuf *rb, int n) {
-  ATOMIC_FETCH_ADD(rb->write_offset, n);
+  rb->write_offset.fetch_add(n);
 }
 
 void *ringbuf_write_ptr(struct ringbuf *rb) {
-  int write_offset = ATOMIC_LOAD(rb->write_offset);
+  int64_t write_offset = rb->write_offset.load();
   return rb->data + (write_offset % rb->capacity);
 }
 
 void ringbuf_advance_read_ptr(struct ringbuf *rb, int n) {
-  ATOMIC_FETCH_ADD(rb->write_offset, n);
+  rb->read_offset.fetch_add(n);
 }
 
 void *ringbuf_read_ptr(struct ringbuf *rb) {
-  int read_offset = ATOMIC_LOAD(rb->read_offset);
+  int64_t read_offset = rb->read_offset.load();
   return rb->data + (read_offset % rb->capacity);
 }
 
@@ -39,9 +35,9 @@ int ringbuf_remaining(struct ringbuf *rb) {
 }
 
 int ringbuf_available(struct ringbuf *rb) {
-  int read = ATOMIC_LOAD(rb->read_offset);
-  int write = ATOMIC_LOAD(rb->write_offset);
-  int available = write - read;
+  int64_t read = rb->read_offset.load();
+  int64_t write = rb->write_offset.load();
+  int available = (int)(write - read);
   CHECK(available >= 0 && available <= rb->capacity);
   return available;
 }
diff --git a/src/sys/atomic.h b/src/sys/atomic.h
deleted file mode 100644
index eebd97a9..00000000
--- a/src/sys/atomic.h
+++ /dev/null
@@ -1,40 +0,0 @@
-#ifndef SYS_ATOMIC_H
-#define SYS_ATOMIC_H
-
-#ifdef __cplusplus
-
-#include <atomic>
-
-struct re_atomic_int {
-    std::atomic<int> x;
-};
-
-struct re_atomic_long {
-    std::atomic<long> x;
-};
-
-#define ATOMIC_LOAD(a) (a.x.load())
-#define ATOMIC_FETCH_ADD(a, value) (a.x.fetch_add(value))
-#define ATOMIC_STORE(a, value) (a.x.store(value))
-#define ATOMIC_EXCHANGE(a, value) (a.x.exchange(value))
-
-#else
-
-#include <stdatomic.h>
-
-struct re_atomic_int {
-    atomic_int x;
-};
-
-struct re_atomic_long {
-    atomic_long x;
-};
-
-#define ATOMIC_LOAD(a) atomic_load(&a.x)
-#define ATOMIC_FETCH_ADD(a, value) atomic_fetch_add(&a.x, value)
-#define ATOMIC_STORE(a, value) atomic_store(&a.x, value)
-#define ATOMIC_EXCHANGE(a, value) atomic_exchange(&a.x, value)
-
-#endif
-
-#endif