Index: content/browser/geolocation/wifi_data.cc |
diff --git a/content/browser/geolocation/wifi_data.cc b/content/browser/geolocation/wifi_data.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..d82e6f442f0334ac3db46680335e216416423f70 |
--- /dev/null |
+++ b/content/browser/geolocation/wifi_data.cc |
@@ -0,0 +1,57 @@ |
+// Copyright 2013 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#include "content/browser/geolocation/wifi_data.h" |
+ |
+#include <stddef.h> |
+#include <stdint.h> |
+ |
+#include <algorithm> |
+#include <limits> |
+ |
+#include "base/logging.h" |
+ |
+namespace content { |
+ |
+AccessPointData::AccessPointData() |
+ : radio_signal_strength(std::numeric_limits<int32_t>::min()), |
+ channel(std::numeric_limits<int32_t>::min()), |
+ signal_to_noise(std::numeric_limits<int32_t>::min()) {} |
+ |
+AccessPointData::~AccessPointData() {} |
+ |
+WifiData::WifiData() {} |
+ |
+WifiData::WifiData(const WifiData& other) = default; |
+ |
+WifiData::~WifiData() {} |
+ |
+bool WifiData::DiffersSignificantly(const WifiData& other) const { |
+ // More than 4 or 50% of access points added or removed is significant. |
+ static const size_t kMinChangedAccessPoints = 4; |
+ const size_t min_ap_count = |
+ std::min(access_point_data.size(), other.access_point_data.size()); |
+ const size_t max_ap_count = |
+ std::max(access_point_data.size(), other.access_point_data.size()); |
+ const size_t difference_threadhold = std::min(kMinChangedAccessPoints, |
+ min_ap_count / 2); |
+ if (max_ap_count > min_ap_count + difference_threadhold) |
+ return true; |
+ // Compute size of intersection of old and new sets. |
+ size_t num_common = 0; |
+ for (AccessPointDataSet::const_iterator iter = access_point_data.begin(); |
+ iter != access_point_data.end(); |
+ iter++) { |
+ if (other.access_point_data.find(*iter) != |
+ other.access_point_data.end()) { |
+ ++num_common; |
+ } |
+ } |
+ DCHECK(num_common <= min_ap_count); |
+ |
+ // Test how many have changed. |
+ return max_ap_count > num_common + difference_threadhold; |
+} |
+ |
+} // namespace content |