// Copyright 2014 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/spdy/hpack_string_util.h" #include <cstddef> #include <cstring> #include "base/basictypes.h" #include "base/logging.h" #include "base/strings/string_piece.h" #include "testing/gtest/include/gtest/gtest.h" namespace net { namespace { using std::string; // Make sure StringPiecesEqualConstantTime() behaves like the regular // string equality operator. TEST(HpackStringUtilTest, StringPiecesEqualConstantTime) { EXPECT_TRUE(StringPiecesEqualConstantTime("foo", "foo")); EXPECT_FALSE(StringPiecesEqualConstantTime("foo", "foox")); EXPECT_FALSE(StringPiecesEqualConstantTime("foo", "bar")); } // TODO(jgraettinger): Support this benchmark. /* enum BM_StringPieceEqualityType { STRCMP_EQUAL, STRCMP_FIRST_CHAR_DIFFERS, STRING_PIECES_EQUAL_CONSTANT_TIME_EQUAL, STRING_PIECES_EQUAL_CONSTANT_TIME_FIRST_CHAR_DIFFERS, }; void BM_StringPieceEquality(int iters, int size, int type_int) { BM_StringPieceEqualityType type = static_cast<BM_StringPieceEqualityType>(type_int); string str_a(size, 'x'); string str_b(size, 'x'); int result = 0; switch (type) { case STRCMP_EQUAL: for (int i = 0; i < iters; ++i) { result |= std::strcmp(str_a.c_str(), str_b.c_str()); } CHECK_EQ(result, 0); return; case STRCMP_FIRST_CHAR_DIFFERS: str_b[0] = 'y'; for (int i = 0; i < iters; ++i) { result |= std::strcmp(str_a.c_str(), str_b.c_str()); } CHECK_LT(result, 0); return; case STRING_PIECES_EQUAL_CONSTANT_TIME_EQUAL: for (int i = 0; i < iters; ++i) { result |= StringPiecesEqualConstantTime(str_a, str_b); } CHECK_EQ(result, 1); return; case STRING_PIECES_EQUAL_CONSTANT_TIME_FIRST_CHAR_DIFFERS: str_b[0] = 'y'; for (int i = 0; i < iters; ++i) { result |= StringPiecesEqualConstantTime(str_a, str_b); } CHECK_EQ(result, 0); return; } DCHECK(false); } // Results should resemble the table below, where 0 and 1 are clearly // different (STRCMP), but 2 and 3 are roughly the same // (STRING_PIECES_EQUAL_CONSTANT_TIME). // // DEBUG: Benchmark Time(ns) CPU(ns) Iterations // ------------------------------------------------------------------- // DEBUG: BM_StringPieceEquality/1M/0 77796 77141 7778 // DEBUG: BM_StringPieceEquality/1M/1 10 10 70000000 // DEBUG: BM_StringPieceEquality/1M/2 7729735 7700000 100 // DEBUG: BM_StringPieceEquality/1M/3 7803051 7800000 100 BENCHMARK(BM_StringPieceEquality) ->ArgPair(1<<20, STRCMP_EQUAL) ->ArgPair(1<<20, STRCMP_FIRST_CHAR_DIFFERS) ->ArgPair(1<<20, STRING_PIECES_EQUAL_CONSTANT_TIME_EQUAL) ->ArgPair(1<<20, STRING_PIECES_EQUAL_CONSTANT_TIME_FIRST_CHAR_DIFFERS); */ } // namespace } // namespace net