/*
 *  Copyright (c) 2012 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#ifndef LIBVPX_TEST_REGISTER_STATE_CHECK_H_
#define LIBVPX_TEST_REGISTER_STATE_CHECK_H_

#ifdef _WIN64

#define _WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winnt.h>

#include "third_party/googletest/src/include/gtest/gtest.h"

namespace testing {
namespace internal {

inline bool operator==(const M128A& lhs, const M128A& rhs) {
  return (lhs.Low == rhs.Low && lhs.High == rhs.High);
}

}  // namespace internal
}  // namespace testing

namespace libvpx_test {

// Compares the state of xmm[6-15] at construction with their state at
// destruction. These registers should be preserved by the callee on
// Windows x64.
// Usage:
// {
//   RegisterStateCheck reg_check;
//   FunctionToVerify();
// }
class RegisterStateCheck {
 public:
  RegisterStateCheck() { initialized_ = StoreRegisters(&pre_context_); }
  ~RegisterStateCheck() { EXPECT_TRUE(Check()); }

 private:
  static bool StoreRegisters(CONTEXT* const context) {
    const HANDLE this_thread = GetCurrentThread();
    EXPECT_TRUE(this_thread != NULL);
    context->ContextFlags = CONTEXT_FLOATING_POINT;
    const bool context_saved = GetThreadContext(this_thread, context) == TRUE;
    EXPECT_TRUE(context_saved) << "GetLastError: " << GetLastError();
    return context_saved;
  }

  // Compares the register state. Returns true if the states match.
  bool Check() const {
    if (!initialized_) return false;
    CONTEXT post_context;
    if (!StoreRegisters(&post_context)) return false;

    const M128A* xmm_pre = &pre_context_.Xmm6;
    const M128A* xmm_post = &post_context.Xmm6;
    for (int i = 6; i <= 15; ++i) {
      EXPECT_EQ(*xmm_pre, *xmm_post) << "xmm" << i << " has been modified!";
      ++xmm_pre;
      ++xmm_post;
    }
    return !testing::Test::HasNonfatalFailure();
  }

  bool initialized_;
  CONTEXT pre_context_;
};

#define REGISTER_STATE_CHECK(statement) do { \
  libvpx_test::RegisterStateCheck reg_check; \
  statement;                               \
} while (false)

}  // namespace libvpx_test

#else  // !_WIN64

namespace libvpx_test {

class RegisterStateCheck {};
#define REGISTER_STATE_CHECK(statement) statement

}  // namespace libvpx_test

#endif  // _WIN64

#endif  // LIBVPX_TEST_REGISTER_STATE_CHECK_H_