1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "content/browser/geolocation/wifi_data.h" 6 7 #include <algorithm> 8 9 #include "base/logging.h" 10 11 namespace content { 12 13 AccessPointData::AccessPointData() 14 : radio_signal_strength(kint32min), 15 channel(kint32min), 16 signal_to_noise(kint32min) { 17 } 18 19 AccessPointData::~AccessPointData() {} 20 21 WifiData::WifiData() {} 22 23 WifiData::~WifiData() {} 24 25 bool WifiData::DiffersSignificantly(const WifiData& other) const { 26 // More than 4 or 50% of access points added or removed is significant. 27 static const size_t kMinChangedAccessPoints = 4; 28 const size_t min_ap_count = 29 std::min(access_point_data.size(), other.access_point_data.size()); 30 const size_t max_ap_count = 31 std::max(access_point_data.size(), other.access_point_data.size()); 32 const size_t difference_threadhold = std::min(kMinChangedAccessPoints, 33 min_ap_count / 2); 34 if (max_ap_count > min_ap_count + difference_threadhold) 35 return true; 36 // Compute size of intersection of old and new sets. 37 size_t num_common = 0; 38 for (AccessPointDataSet::const_iterator iter = access_point_data.begin(); 39 iter != access_point_data.end(); 40 iter++) { 41 if (other.access_point_data.find(*iter) != 42 other.access_point_data.end()) { 43 ++num_common; 44 } 45 } 46 DCHECK(num_common <= min_ap_count); 47 48 // Test how many have changed. 49 return max_ap_count > num_common + difference_threadhold; 50 } 51 52 } // namespace content 53
