git-svn-id: http://webrtc.googlecode.com/svn/trunk@6 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/system_wrappers/source/cpu_mac.cc b/system_wrappers/source/cpu_mac.cc
new file mode 100644
index 0000000..c2a11e1
--- /dev/null
+++ b/system_wrappers/source/cpu_mac.cc
@@ -0,0 +1,132 @@
+/*
+ *  Copyright (c) 2011 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 "cpu_mac.h"
+
+#include <iostream>
+#include <mach/mach.h>
+#include <mach/mach_error.h>
+
+#include "tick_util.h"
+
+namespace webrtc {
+CpuWrapperMac::CpuWrapperMac() : _cpuUsage(NULL)
+{
+    natural_t cpuCount;
+    processor_info_array_t infoArray;
+    mach_msg_type_number_t infoCount;
+
+    kern_return_t error = host_processor_info(mach_host_self(),
+                                              PROCESSOR_CPU_LOAD_INFO,
+                                              &cpuCount,
+                                              &infoArray,
+                                              &infoCount);
+    if (error)
+    {
+        return;
+    }
+
+    _cpuUsage = new WebRtc_UWord32[cpuCount];
+    _lastTickCount = new WebRtc_Word64[cpuCount];
+    _lastTime = TickTime::MillisecondTimestamp();
+
+    processor_cpu_load_info_data_t* cpuLoadInfo =
+        (processor_cpu_load_info_data_t*) infoArray;
+    for (unsigned int cpu= 0; cpu < cpuCount; cpu++)
+    {
+        WebRtc_Word64 ticks = 0;
+        for (int state = 0; state < 2; state++)
+        {
+            ticks += cpuLoadInfo[cpu].cpu_ticks[state];
+        }
+        _lastTickCount[cpu] = ticks;
+    }
+    vm_deallocate(mach_task_self(), (vm_address_t)infoArray, infoCount);
+}
+
+CpuWrapperMac::~CpuWrapperMac()
+{
+    delete _cpuUsage;
+    delete _lastTickCount;
+}
+
+WebRtc_Word32 CpuWrapperMac::CpuUsage()
+{
+    WebRtc_UWord32 numCores;
+    WebRtc_UWord32* array = NULL;
+    return CpuUsageMultiCore(numCores, array);
+}
+
+WebRtc_Word32
+CpuWrapperMac::CpuUsageMultiCore(WebRtc_UWord32& numCores,
+                                 WebRtc_UWord32*& array)
+{
+    natural_t cpuCount;
+    processor_info_array_t infoArray;
+    mach_msg_type_number_t infoCount;
+
+    // sanity check
+    if(_cpuUsage == NULL)
+    {
+        return -1;
+    }
+    WebRtc_Word64 now = TickTime::MillisecondTimestamp();
+    WebRtc_Word64 timeDiffMS = now - _lastTime;
+    // TODO(hellner) why block here? Why not just return the old
+    //                          value? Is this behavior consistent across all
+    //                          platforms?
+    // Make sure that at least 500 ms pass between calls.
+    if(timeDiffMS < 500)
+    {
+        usleep((500-timeDiffMS)*1000);
+        return CpuUsageMultiCore(numCores, array);
+    }
+    _lastTime = now;
+
+     kern_return_t error = host_processor_info(mach_host_self(),
+                                              PROCESSOR_CPU_LOAD_INFO,
+                                              &cpuCount,
+                                              &infoArray,
+                                              &infoCount);
+    if (error)
+    {
+        return -1;
+    }
+
+    processor_cpu_load_info_data_t* cpuLoadInfo =
+        (processor_cpu_load_info_data_t*) infoArray;
+
+    WebRtc_Word32 totalCpuUsage = 0;
+    for (unsigned int cpu = 0; cpu < cpuCount; cpu++)
+    {
+        WebRtc_Word64 ticks = 0;
+        for (int state = 0; state < 2; state++)
+        {
+            ticks += cpuLoadInfo[cpu].cpu_ticks[state];
+        }
+        if(timeDiffMS <= 0)
+        {
+            _cpuUsage[cpu] = 0;
+        }else {
+            _cpuUsage[cpu] = (WebRtc_UWord32)((1000 *
+                                              (ticks - _lastTickCount[cpu])) /
+                                              timeDiffMS);
+        }
+        _lastTickCount[cpu] = ticks;
+        totalCpuUsage += _cpuUsage[cpu];
+    }
+
+    vm_deallocate(mach_task_self(), (vm_address_t)infoArray, infoCount);
+
+    numCores = cpuCount;
+    array = _cpuUsage;
+    return totalCpuUsage/cpuCount;
+}
+} // namespace webrtc