Trivial implementation of distinguished name comparison.

BUG=410574

Review URL: https://codereview.chromium.org/1126023002

Cr-Commit-Position: refs/heads/master@{#329140}

3 files changed, 26 insertions, 0 deletions

diff --git a/net/der/input.cc b/net/der/input.cc
index f896bb8..004034e 100644
--- a/net/der/input.cc
+++ b/net/der/input.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <string.h>
+
 #include "base/logging.h"
 #include "net/der/input.h"
 
@@ -19,6 +21,12 @@ Input::Input(const std::string& s)
     : data_(reinterpret_cast<const uint8_t*>(s.data())), len_(s.size()) {
 }
 
+bool Input::Equals(const Input& other) const {
+  if (len_ != other.len_)
+    return false;
+  return memcmp(data_, other.data_, len_) == 0;
+}
+
 ByteReader::ByteReader(const Input& in)
     : data_(in.UnsafeData()), len_(in.Length()) {
 }
diff --git a/net/der/input.h b/net/der/input.h
index 667bd89..5814375 100644
--- a/net/der/input.h
+++ b/net/der/input.h
@@ -50,6 +50,9 @@ class NET_EXPORT_PRIVATE Input {
   // Returns the length in bytes of an Input's data.
   size_t Length() const { return len_; }
 
+  // Return true if the Input's data and |other|'s data are byte-wise equal.
+  bool Equals(const Input& other) const;
+
   // Returns a pointer to the Input's data. This method is marked as "unsafe"
   // because access to the Input's data should be done through ByteReader
   // instead. This method should only be used where using a ByteReader truly
diff --git a/net/der/input_unittest.cc b/net/der/input_unittest.cc
index a6a9b8c..e8145b5 100644
--- a/net/der/input_unittest.cc
+++ b/net/der/input_unittest.cc
@@ -12,6 +12,21 @@ namespace test {
 
 const uint8_t kInput[] = {'t', 'e', 's', 't'};
 
+TEST(InputTest, Equals) {
+  Input test(kInput, arraysize(kInput));
+  Input test2(kInput, arraysize(kInput));
+  EXPECT_TRUE(test.Equals(test2));
+
+  std::string input_copy(reinterpret_cast<const char*>(kInput),
+                         arraysize(kInput));
+  Input test_copy(input_copy);
+  EXPECT_TRUE(test.Equals(test_copy));
+
+  Input test_truncated(kInput, arraysize(kInput) - 1);
+  EXPECT_FALSE(test.Equals(test_truncated));
+  EXPECT_FALSE(test_truncated.Equals(test));
+}
+
 TEST(ByteReaderTest, NoReadPastEnd) {
   ByteReader reader(Input(nullptr, 0));
   uint8_t data;