Support for Signal calls.

Merge in RedPhone

// FREEBIE

jni/webrtc/system_wrappers/source/atomic32_posix.cc

@@ -0,0 +1,53 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/system_wrappers/interface/atomic32.h"
+
+#include <assert.h>
+#include <inttypes.h>
+#include <malloc.h>
+
+#include "webrtc/common_types.h"
+
+namespace webrtc {
+
+Atomic32::Atomic32(int32_t initial_value)
+    : value_(initial_value) {
+  assert(Is32bitAligned());
+}
+
+Atomic32::~Atomic32() {
+}
+
+int32_t Atomic32::operator++() {
+  return __sync_fetch_and_add(&value_, 1) + 1;
+}
+
+int32_t Atomic32::operator--() {
+  return __sync_fetch_and_sub(&value_, 1) - 1;
+}
+
+int32_t Atomic32::operator+=(int32_t value) {
+  int32_t return_value = __sync_fetch_and_add(&value_, value);
+  return_value += value;
+  return return_value;
+}
+
+int32_t Atomic32::operator-=(int32_t value) {
+  int32_t return_value = __sync_fetch_and_sub(&value_, value);
+  return_value -= value;
+  return return_value;
+}
+
+bool Atomic32::CompareExchange(int32_t new_value, int32_t compare_value) {
+  return __sync_bool_compare_and_swap(&value_, compare_value, new_value);
+}
+
+}  // namespace webrtc