Avoid heap allocations in IPAddress

net/cert/internal/name_constraints.cc

 // Copyright 2015 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/cert/internal/name_constraints.h"
 
 #include <limits.h>
 
 #include <memory>
 
@@ skipping 86 matching lines @@
       name[name.size() - dns_constraint.size() - 1] == '.') {
     return true;
   }
   // Trailing text matches, but not in a subtree (e.g., "foobar.com" is not a
   // match for "bar.com").
   return false;
 }
 
 // Return true if the bitmask |mask| contains only zeros after the first
 // |prefix_length| bits.
-bool IsSuffixZero(const std::vector<uint8_t>& mask, unsigned prefix_length) {
+bool IsSuffixZero(const IPAddress::IPAddressBytes& mask,
+                  unsigned prefix_length) {
   size_t zero_bits = mask.size() * CHAR_BIT - prefix_length;
   size_t zero_bytes = zero_bits / CHAR_BIT;
   std::vector<uint8_t> zeros(zero_bytes, 0);
   if (memcmp(zeros.data(), mask.data() + mask.size() - zero_bytes, zero_bytes))
     return false;
   size_t leftover_bits = zero_bits % CHAR_BIT;
   if (leftover_bits) {
     uint8_t b = mask[mask.size() - zero_bytes - 1];
     for (size_t i = 0; i < leftover_bits; ++i) {
       if (b & (1 << i))
@@ skipping 430 matching lines @@
 
   return false;
 }
 
 int NameConstraints::ConstrainedNameTypes() const {
   return (permitted_subtrees_.present_name_types |
           excluded_subtrees_.present_name_types);
 }
 
 }  // namespace net