Added NetworkInterface::network_prefix

net/base/net_util.cc

 // Copyright (c) 2012 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 "net/base/net_util.h"
 
 #include <algorithm>
 #include <iterator>
 #include <map>
 
@@ skipping 2124 matching lines @@
       }
 
       default:
         NOTREACHED();
     }
   }
 
   return false;
 }
 
-NetworkInterface::NetworkInterface() {
+NetworkInterface::NetworkInterface() : network_prefix(0) {
 }
 
 NetworkInterface::NetworkInterface(const std::string& name,
-                                   const IPAddressNumber& address)
-    : name(name), address(address) {
+                                   const IPAddressNumber& address,
+                                   uint8 network_prefix)
+    : name(name), address(address), network_prefix(network_prefix) {
 }
 
 NetworkInterface::~NetworkInterface() {
 }
 
+unsigned CommonPrefixLength(const IPAddressNumber& a1,
+                            const IPAddressNumber& a2) {
+  DCHECK_EQ(a1.size(), a2.size());
+  for (size_t i = 0; i < a1.size(); ++i) {
+    unsigned diff = a1[i] ^ a2[i];
+    if (!diff)
+      continue;
+    for (unsigned j = 0; j < CHAR_BIT; ++j) {
+      if (diff & (1 << (CHAR_BIT - 1)))
+        return i * CHAR_BIT + j;
+      diff <<= 1;
+    }
+    NOTREACHED();
+  }
+  return a1.size() * CHAR_BIT;
+}
+
+unsigned MaskPrefixLength(const IPAddressNumber& mask) {
+  IPAddressNumber all_ones(mask.size(), 0xFF);
+  return CommonPrefixLength(mask, all_ones);
+}
+
 }  // namespace net