From d42dfdf4b903763997d47b6e2214c2ce33b9bf8e Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Wed, 9 Jun 2021 21:59:17 +0800
Subject: import(life): Add operating system experiement.

---
 works/life/operating-system-experiment/.gitignore  |  5 ++
 works/life/operating-system-experiment/Base.h      | 22 +++++++
 .../operating-system-experiment/CMakeLists.txt     | 17 ++++++
 works/life/operating-system-experiment/Thread.cpp  | 67 +++++++++++++++++++++
 works/life/operating-system-experiment/Thread.h    | 68 ++++++++++++++++++++++
 works/life/operating-system-experiment/main.cpp    | 16 +++++
 6 files changed, 195 insertions(+)
 create mode 100644 works/life/operating-system-experiment/.gitignore
 create mode 100644 works/life/operating-system-experiment/Base.h
 create mode 100644 works/life/operating-system-experiment/CMakeLists.txt
 create mode 100644 works/life/operating-system-experiment/Thread.cpp
 create mode 100644 works/life/operating-system-experiment/Thread.h
 create mode 100644 works/life/operating-system-experiment/main.cpp

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/.gitignore b/works/life/operating-system-experiment/.gitignore
new file mode 100644
index 0000000..502724c
--- /dev/null
+++ b/works/life/operating-system-experiment/.gitignore
@@ -0,0 +1,5 @@
+*.exe
+*.pdb
+.cache
+build
+compile_commands.json
\ No newline at end of file
diff --git a/works/life/operating-system-experiment/Base.h b/works/life/operating-system-experiment/Base.h
new file mode 100644
index 0000000..b3ac1ee
--- /dev/null
+++ b/works/life/operating-system-experiment/Base.h
@@ -0,0 +1,22 @@
+#ifndef HEADER_BASE_H
+#define HEADER_BASE_H
+
+#ifdef _WIN32
+#define CRU_WINDOWS 1
+#endif
+
+#ifdef CRU_WINDOWS
+#include <Windows.h>
+#endif
+
+#ifdef CRU_WINDOWS
+#ifdef CRU_EXPORT_API
+#define CRU_API __declspec(dllexport)
+#else
+#define CRU_API __declspec(dllimport)
+#endif
+#else
+#define CRU_API
+#endif
+
+#endif
\ No newline at end of file
diff --git a/works/life/operating-system-experiment/CMakeLists.txt b/works/life/operating-system-experiment/CMakeLists.txt
new file mode 100644
index 0000000..2c46b0f
--- /dev/null
+++ b/works/life/operating-system-experiment/CMakeLists.txt
@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.20)
+
+set(CMAKE_TOOLCHAIN_FILE $ENV{VCPKG_INSTALLATION_ROOT}/scripts/buildsystems/vcpkg.cmake
+  CACHE STRING "Vcpkg toolchain file")
+
+project(operating-system-experiment)
+
+set(CMAKE_CXX_STANDARD 17)
+
+find_package(fmt CONFIG REQUIRED)
+find_package(Microsoft.GSL CONFIG REQUIRED)
+add_library(cru_system SHARED Thread.cpp)
+target_link_libraries(cru_system PUBLIC Microsoft.GSL::GSL fmt::fmt)
+target_compile_definitions(cru_system PUBLIC CRU_EXPORT_API)
+
+add_executable(main main.cpp)
+target_link_libraries(main PRIVATE cru_system)
\ No newline at end of file
diff --git a/works/life/operating-system-experiment/Thread.cpp b/works/life/operating-system-experiment/Thread.cpp
new file mode 100644
index 0000000..b91ca69
--- /dev/null
+++ b/works/life/operating-system-experiment/Thread.cpp
@@ -0,0 +1,67 @@
+#include "Thread.h"
+
+#include <cassert>
+#include <exception>
+#include <utility>
+
+namespace cru {
+Thread::Thread(Thread &&other) noexcept
+    : joined_(other.joined_), thread_handle_(other.thread_handle_) {
+  other.joined_ = false;
+  other.thread_handle_ = nullptr;
+}
+
+Thread &Thread::operator=(Thread &&other) noexcept {
+  if (this != &other) {
+    joined_ = other.joined_;
+    thread_handle_ = other.thread_handle_;
+    other.joined_ = false;
+    other.thread_handle_ = nullptr;
+  }
+
+  return *this;
+}
+
+Thread::~Thread() { Destroy(); }
+
+void Thread::Join() {
+  assert(thread_handle_);
+  joined_ = true;
+  WaitForSingleObject(thread_handle_, INFINITE);
+}
+
+void Thread::Detach() {
+  assert(thread_handle_);
+  detached_ = true;
+}
+
+void Thread::swap(Thread &other) noexcept {
+#ifdef CRU_WINDOWS
+  Thread temp = std::move(*this);
+  *this = std::move(other);
+  other = std::move(temp);
+#else
+#endif
+}
+
+void Thread::Destroy() noexcept {
+  if (!detached_ && !joined_ && thread_handle_ != nullptr) {
+    std::terminate();
+  } else {
+    joined_ = false;
+    thread_handle_ = nullptr;
+  }
+}
+
+namespace details {
+#ifdef CRU_WINDOWS
+DWORD WINAPI ThreadProc(_In_ LPVOID lpParameter) {
+  auto p = static_cast<std::function<void()> *>(lpParameter);
+  (*p)();
+  delete p;
+  return 0;
+}
+#else
+#endif
+} // namespace details
+} // namespace cru
\ No newline at end of file
diff --git a/works/life/operating-system-experiment/Thread.h b/works/life/operating-system-experiment/Thread.h
new file mode 100644
index 0000000..c71c11f
--- /dev/null
+++ b/works/life/operating-system-experiment/Thread.h
@@ -0,0 +1,68 @@
+#ifndef HEADER_THREAD_H
+#define HEADER_THREAD_H
+
+#include "Base.h"
+
+#ifdef __cplusplus
+
+#include <functional>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+namespace cru {
+class CRU_API Thread {
+public:
+  Thread() = default;
+  template <typename Fn, typename... Args> Thread(Fn &&process, Args &&...args);
+  Thread(const Thread &other) = delete;
+  Thread(Thread &&other) noexcept;
+  Thread &operator=(const Thread &other) = delete;
+  Thread &operator=(Thread &&other) noexcept;
+  ~Thread();
+
+public:
+  void Join();
+  void Detach();
+
+  void swap(Thread &other) noexcept;
+
+private:
+  void Destroy() noexcept;
+
+private:
+  bool detached_ = false;
+  bool joined_ = false;
+
+#ifdef CRU_WINDOWS
+  DWORD thread_id_ = 0;
+  HANDLE thread_handle_ = nullptr;
+#endif
+};
+
+namespace details {
+#ifdef CRU_WINDOWS
+CRU_API DWORD WINAPI ThreadProc(_In_ LPVOID lpParameter);
+#else
+#endif
+} // namespace details
+
+template <typename Fn, typename... Args>
+Thread::Thread(Fn &&process, Args &&...args) {
+  std::tuple<std::decay_t<Args>...> a{std::forward<Args>(args)...};
+  auto p = new std::function<void()>(
+      [process = std::forward<Fn>(process), args = std::move(a)]() {
+        std::apply(process, std::move(args));
+      });
+
+#ifdef CRU_WINDOWS
+  thread_handle_ = ::CreateThread(nullptr, 0, &::cru::details::ThreadProc,
+                                  static_cast<void *>(p), 0, &thread_id_);
+#endif
+};
+} // namespace cru
+
+#endif
+
+#endif
diff --git a/works/life/operating-system-experiment/main.cpp b/works/life/operating-system-experiment/main.cpp
new file mode 100644
index 0000000..ada8c85
--- /dev/null
+++ b/works/life/operating-system-experiment/main.cpp
@@ -0,0 +1,16 @@
+#include "Thread.h"
+
+#include <iostream>
+#include <string>
+
+int main() {
+  cru::Thread thread1([](const std::string &s) { std::cout << s; },
+                      "Hello world! 1\n");
+  thread1.Join();
+
+  cru::Thread thread2([](const std::string &s) { std::cout << s; },
+                      "Hello world! 2\n");
+  thread2.Join();
+
+  return 0;
+}
-- 
cgit v1.2.3


From 8bdb5db67fa3eeda755511f91fd257bde548a18f Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Wed, 9 Jun 2021 22:28:01 +0800
Subject: import(life): ...

---
 works/life/operating-system-experiment/Base.h      |  4 --
 .../operating-system-experiment/CMakeLists.txt     |  4 ++
 works/life/operating-system-experiment/Thread.cpp  | 53 ++++++++++++++++++++--
 works/life/operating-system-experiment/Thread.h    | 17 +++++++
 4 files changed, 69 insertions(+), 9 deletions(-)

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/Base.h b/works/life/operating-system-experiment/Base.h
index b3ac1ee..6964c1c 100644
--- a/works/life/operating-system-experiment/Base.h
+++ b/works/life/operating-system-experiment/Base.h
@@ -5,10 +5,6 @@
 #define CRU_WINDOWS 1
 #endif
 
-#ifdef CRU_WINDOWS
-#include <Windows.h>
-#endif
-
 #ifdef CRU_WINDOWS
 #ifdef CRU_EXPORT_API
 #define CRU_API __declspec(dllexport)
diff --git a/works/life/operating-system-experiment/CMakeLists.txt b/works/life/operating-system-experiment/CMakeLists.txt
index 2c46b0f..540574b 100644
--- a/works/life/operating-system-experiment/CMakeLists.txt
+++ b/works/life/operating-system-experiment/CMakeLists.txt
@@ -12,6 +12,10 @@ find_package(Microsoft.GSL CONFIG REQUIRED)
 add_library(cru_system SHARED Thread.cpp)
 target_link_libraries(cru_system PUBLIC Microsoft.GSL::GSL fmt::fmt)
 target_compile_definitions(cru_system PUBLIC CRU_EXPORT_API)
+if(UNIX)
+target_link_libraries(cru_system PUBLIC pthread)
+endif()
+
 
 add_executable(main main.cpp)
 target_link_libraries(main PRIVATE cru_system)
\ No newline at end of file
diff --git a/works/life/operating-system-experiment/Thread.cpp b/works/life/operating-system-experiment/Thread.cpp
index b91ca69..8230c1c 100644
--- a/works/life/operating-system-experiment/Thread.cpp
+++ b/works/life/operating-system-experiment/Thread.cpp
@@ -2,21 +2,36 @@
 
 #include <cassert>
 #include <exception>
+#include <pthread.h>
 #include <utility>
 
 namespace cru {
 Thread::Thread(Thread &&other) noexcept
-    : joined_(other.joined_), thread_handle_(other.thread_handle_) {
+    : detached_(other.detached_), joined_(other.joined_),
+#ifdef CRU_WINDOWS
+      thread_handle_(other.thread_handle_)
+#else
+      thread_(std::move(other.thread_))
+#endif
+{
   other.joined_ = false;
+#ifdef CRU_WINDOWS
   other.thread_handle_ = nullptr;
-}
+#endif
+} // namespace cru
 
 Thread &Thread::operator=(Thread &&other) noexcept {
   if (this != &other) {
+    detached_ = other.detached_;
     joined_ = other.joined_;
+#ifdef CRU_WINDOWS
     thread_handle_ = other.thread_handle_;
-    other.joined_ = false;
     other.thread_handle_ = nullptr;
+#else
+    thread_ = std::move(other.thread_);
+#endif
+    other.detached_ = false;
+    other.joined_ = false;
   }
 
   return *this;
@@ -25,13 +40,23 @@ Thread &Thread::operator=(Thread &&other) noexcept {
 Thread::~Thread() { Destroy(); }
 
 void Thread::Join() {
-  assert(thread_handle_);
   joined_ = true;
+#ifdef CRU_WINDOWS
+  assert(thread_handle_);
   WaitForSingleObject(thread_handle_, INFINITE);
+#else
+  assert(thread_);
+  auto c = pthread_join(*thread_, nullptr);
+  assert(c == 0);
+#endif
 }
 
 void Thread::Detach() {
+#ifdef CRU_WINDOWS
   assert(thread_handle_);
+#else
+  assert(thread_);
+#endif
   detached_ = true;
 }
 
@@ -45,11 +70,22 @@ void Thread::swap(Thread &other) noexcept {
 }
 
 void Thread::Destroy() noexcept {
-  if (!detached_ && !joined_ && thread_handle_ != nullptr) {
+  if (!detached_ && !joined_ &&
+#ifdef CRU_WINDOWS
+      thread_handle_ != nullptr
+#else
+      thread_ != nullptr
+#endif
+  ) {
     std::terminate();
   } else {
+    detached_ = false;
     joined_ = false;
+#ifdef CRU_WINDOWS
     thread_handle_ = nullptr;
+#else
+    thread_ = nullptr;
+#endif
   }
 }
 
@@ -62,6 +98,13 @@ DWORD WINAPI ThreadProc(_In_ LPVOID lpParameter) {
   return 0;
 }
 #else
+void *ThreadProc(void *data) {
+  auto p = static_cast<std::function<void()> *>(data);
+  (*p)();
+  delete p;
+  return nullptr;
+}
+
 #endif
 } // namespace details
 } // namespace cru
\ No newline at end of file
diff --git a/works/life/operating-system-experiment/Thread.h b/works/life/operating-system-experiment/Thread.h
index c71c11f..79c1728 100644
--- a/works/life/operating-system-experiment/Thread.h
+++ b/works/life/operating-system-experiment/Thread.h
@@ -3,9 +3,17 @@
 
 #include "Base.h"
 
+#ifdef CRU_WINDOWS
+#include <Windows.h>
+#else
+#include <pthread.h>
+#endif
+
 #ifdef __cplusplus
 
+#include <cassert>
 #include <functional>
+#include <memory>
 #include <tuple>
 #include <type_traits>
 #include <utility>
@@ -38,6 +46,8 @@ private:
 #ifdef CRU_WINDOWS
   DWORD thread_id_ = 0;
   HANDLE thread_handle_ = nullptr;
+#else
+  std::unique_ptr<pthread_t> thread_;
 #endif
 };
 
@@ -45,6 +55,7 @@ namespace details {
 #ifdef CRU_WINDOWS
 CRU_API DWORD WINAPI ThreadProc(_In_ LPVOID lpParameter);
 #else
+void *ThreadProc(void *data);
 #endif
 } // namespace details
 
@@ -59,6 +70,12 @@ Thread::Thread(Fn &&process, Args &&...args) {
 #ifdef CRU_WINDOWS
   thread_handle_ = ::CreateThread(nullptr, 0, &::cru::details::ThreadProc,
                                   static_cast<void *>(p), 0, &thread_id_);
+  assert(thread_handle_);
+#else
+  thread_.reset(new pthread_t());
+  auto c = pthread_create(thread_.get(), nullptr, details::ThreadProc,
+                          static_cast<void *>(p));
+  assert(c == 0);
 #endif
 };
 } // namespace cru
-- 
cgit v1.2.3


From 8268724a054a42f9446736c42d8f04a0207aa12d Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Wed, 9 Jun 2021 22:30:14 +0800
Subject: import(life): ...

---
 works/life/operating-system-experiment/Thread.h | 1 +
 1 file changed, 1 insertion(+)

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/Thread.h b/works/life/operating-system-experiment/Thread.h
index c71c11f..cdeecac 100644
--- a/works/life/operating-system-experiment/Thread.h
+++ b/works/life/operating-system-experiment/Thread.h
@@ -10,6 +10,7 @@
 #include <type_traits>
 #include <utility>
 #include <vector>
+#include <tuple>
 
 namespace cru {
 class CRU_API Thread {
-- 
cgit v1.2.3


From 93d8feccd79b35fc890fc8629d6da2c2baa57762 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Wed, 9 Jun 2021 22:32:01 +0800
Subject: import(life): ...

---
 works/life/operating-system-experiment/Thread.cpp | 1 -
 1 file changed, 1 deletion(-)

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/Thread.cpp b/works/life/operating-system-experiment/Thread.cpp
index 8230c1c..9d9f5dd 100644
--- a/works/life/operating-system-experiment/Thread.cpp
+++ b/works/life/operating-system-experiment/Thread.cpp
@@ -2,7 +2,6 @@
 
 #include <cassert>
 #include <exception>
-#include <pthread.h>
 #include <utility>
 
 namespace cru {
-- 
cgit v1.2.3


From ef593ba2d445af515214d63bfd3942be9d673467 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Thu, 10 Jun 2021 11:12:25 +0800
Subject: import(life): ...

---
 .../operating-system-experiment/CMakeLists.txt     |  8 ++-
 .../operating-system-experiment/DataRaceDemo.cpp   | 27 ++++++++
 works/life/operating-system-experiment/Mutex.cpp   | 78 ++++++++++++++++++++++
 works/life/operating-system-experiment/Mutex.h     | 44 ++++++++++++
 works/life/operating-system-experiment/Thread.cpp  | 31 +++++++++
 works/life/operating-system-experiment/Thread.h    | 15 ++++-
 6 files changed, 199 insertions(+), 4 deletions(-)
 create mode 100644 works/life/operating-system-experiment/DataRaceDemo.cpp
 create mode 100644 works/life/operating-system-experiment/Mutex.cpp
 create mode 100644 works/life/operating-system-experiment/Mutex.h

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/CMakeLists.txt b/works/life/operating-system-experiment/CMakeLists.txt
index 540574b..806ec74 100644
--- a/works/life/operating-system-experiment/CMakeLists.txt
+++ b/works/life/operating-system-experiment/CMakeLists.txt
@@ -9,13 +9,15 @@ set(CMAKE_CXX_STANDARD 17)
 
 find_package(fmt CONFIG REQUIRED)
 find_package(Microsoft.GSL CONFIG REQUIRED)
-add_library(cru_system SHARED Thread.cpp)
+add_library(cru_system SHARED Thread.cpp Mutex.cpp)
 target_link_libraries(cru_system PUBLIC Microsoft.GSL::GSL fmt::fmt)
 target_compile_definitions(cru_system PUBLIC CRU_EXPORT_API)
 if(UNIX)
 target_link_libraries(cru_system PUBLIC pthread)
 endif()
 
-
 add_executable(main main.cpp)
-target_link_libraries(main PRIVATE cru_system)
\ No newline at end of file
+target_link_libraries(main PRIVATE cru_system)
+
+add_executable(data_race_demo DataRaceDemo.cpp)
+target_link_libraries(data_race_demo PRIVATE cru_system)
diff --git a/works/life/operating-system-experiment/DataRaceDemo.cpp b/works/life/operating-system-experiment/DataRaceDemo.cpp
new file mode 100644
index 0000000..9589eb3
--- /dev/null
+++ b/works/life/operating-system-experiment/DataRaceDemo.cpp
@@ -0,0 +1,27 @@
+#include "Thread.h"
+
+#include <iostream>
+
+int main() {
+  unsigned data = 0;
+
+  cru::Thread t1([&data] {
+    for (int i = 0; i < 100000; i++)
+      data += 10;
+  });
+
+  cru::Thread t2([&data] {
+    for (int i = 0; i < 100000; i++)
+      data += 10;
+  });
+
+  std::cout << "Created thread: " << t1.GetNativeID() << '\n';
+  std::cout << "Created thread: " << t2.GetNativeID() << '\n';
+
+  t1.Join();
+  t2.Join();
+  std::cout << "Answer is " << data << ", which is "
+            << (data == 200000 ? "correct" : "false") << '\n';
+
+  return 0;
+}
diff --git a/works/life/operating-system-experiment/Mutex.cpp b/works/life/operating-system-experiment/Mutex.cpp
new file mode 100644
index 0000000..6a91885
--- /dev/null
+++ b/works/life/operating-system-experiment/Mutex.cpp
@@ -0,0 +1,78 @@
+#include "Mutex.h"
+
+#include <cassert>
+#include <pthread.h>
+
+#ifndef CRU_WINDOWS
+#include <errno.h>
+#endif
+
+namespace cru {
+Mutex::Mutex() {
+#ifdef CRU_WINDOWS
+#else
+  mutex_ = std::make_unique<pthread_mutex_t>();
+
+  auto c = pthread_mutex_init(mutex_.get(), nullptr);
+  assert(c == 0);
+#endif
+}
+
+Mutex::Mutex(Mutex &&other)
+#ifdef CRU_WINDOWS
+#else
+    : mutex_(std::move(other.mutex_))
+#endif
+{
+}
+
+Mutex &Mutex::operator=(Mutex &&other) {
+  if (this != &other) {
+    Destroy();
+    mutex_ = std::move(other.mutex_);
+  }
+  return *this;
+}
+
+Mutex::~Mutex() { Destroy(); }
+
+void Mutex::Lock() {
+#ifdef CRU_WINDOWS
+#else
+  assert(mutex_);
+  auto c = pthread_mutex_lock(mutex_.get());
+  assert(c == 0);
+#endif
+}
+
+bool Mutex::TryLock() {
+#ifdef CRU_WINDOWS
+#else
+  assert(mutex_);
+  auto c = pthread_mutex_trylock(mutex_.get());
+  assert(c == 0 || c == EBUSY);
+  return c == 0 ? true : false;
+#endif
+}
+
+void Mutex::Unlock() {
+#ifdef CRU_WINDOWS
+#else
+  assert(mutex_);
+  auto c = pthread_mutex_unlock(mutex_.get());
+  assert(c == 0);
+#endif
+}
+
+void Mutex::Destroy() {
+#ifdef CRU_WINDOWS
+#else
+  if (mutex_ != nullptr) {
+    auto c = pthread_mutex_destroy(mutex_.get());
+    assert(c);
+    mutex_ = nullptr;
+  }
+#endif
+}
+
+} // namespace cru
diff --git a/works/life/operating-system-experiment/Mutex.h b/works/life/operating-system-experiment/Mutex.h
new file mode 100644
index 0000000..163d9ca
--- /dev/null
+++ b/works/life/operating-system-experiment/Mutex.h
@@ -0,0 +1,44 @@
+#ifndef HEADER_MUTEX_H
+#define HEADER_MUTEX_H
+
+#include "Base.h"
+
+#include <memory>
+
+#ifdef CRU_WINDOWS
+#include <Windows.h>
+#else
+#include <pthread.h>
+#endif
+
+namespace cru {
+class CRU_API Mutex {
+public:
+  Mutex();
+
+  Mutex(const Mutex &other) = delete;
+  Mutex &operator=(const Mutex &other) = delete;
+
+  Mutex(Mutex &&other);
+  Mutex &operator=(Mutex &&other);
+
+  ~Mutex();
+
+public:
+  void Lock();
+  bool TryLock();
+
+  void Unlock();
+
+private:
+  void Destroy();
+
+private:
+#ifdef CRU_WINDOWS
+#else
+  std::unique_ptr<pthread_mutex_t> mutex_;
+#endif
+};
+} // namespace cru
+
+#endif
\ No newline at end of file
diff --git a/works/life/operating-system-experiment/Thread.cpp b/works/life/operating-system-experiment/Thread.cpp
index 9d9f5dd..7e3c784 100644
--- a/works/life/operating-system-experiment/Thread.cpp
+++ b/works/life/operating-system-experiment/Thread.cpp
@@ -59,6 +59,36 @@ void Thread::Detach() {
   detached_ = true;
 }
 
+#ifdef CRU_WINDOWS
+DWORD
+#else
+pthread_t
+#endif
+Thread::GetNativeID() {
+#ifdef CRU_WINDOWS
+  assert(thread_handle_);
+  return thread_id_;
+#else
+  assert(thread_);
+  return *thread_;
+#endif
+}
+
+#ifdef CRU_WINDOWS
+HANDLE
+#else
+pthread_t
+#endif
+Thread::GetNativeHandle() {
+#ifdef CRU_WINDOWS
+  assert(thread_handle_);
+  return thread_handle_;
+#else
+  assert(thread_);
+  return *thread_;
+#endif
+}
+
 void Thread::swap(Thread &other) noexcept {
 #ifdef CRU_WINDOWS
   Thread temp = std::move(*this);
@@ -81,6 +111,7 @@ void Thread::Destroy() noexcept {
     detached_ = false;
     joined_ = false;
 #ifdef CRU_WINDOWS
+    thread_id_ = 0;
     thread_handle_ = nullptr;
 #else
     thread_ = nullptr;
diff --git a/works/life/operating-system-experiment/Thread.h b/works/life/operating-system-experiment/Thread.h
index 69a402c..56fdcb0 100644
--- a/works/life/operating-system-experiment/Thread.h
+++ b/works/life/operating-system-experiment/Thread.h
@@ -18,7 +18,6 @@
 #include <type_traits>
 #include <utility>
 #include <vector>
-#include <tuple>
 
 namespace cru {
 class CRU_API Thread {
@@ -35,6 +34,20 @@ public:
   void Join();
   void Detach();
 
+#ifdef CRU_WINDOWS
+  DWORD
+#else
+  pthread_t
+#endif
+  GetNativeID();
+
+#ifdef CRU_WINDOWS
+  HANDLE
+#else
+  pthread_t
+#endif
+  GetNativeHandle();
+
   void swap(Thread &other) noexcept;
 
 private:
-- 
cgit v1.2.3


From f532667d936500f50447d63333544f603ec06137 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Thu, 10 Jun 2021 11:35:29 +0800
Subject: import(life): ...

---
 .../operating-system-experiment/CMakeLists.txt     |  3 ++
 .../operating-system-experiment/DataRaceDemo.cpp   |  2 +-
 works/life/operating-system-experiment/Mutex.cpp   | 23 +++++++++++-
 works/life/operating-system-experiment/Mutex.h     |  1 +
 .../MutexAvoidDataRaceDemo.cpp                     | 42 ++++++++++++++++++++++
 works/life/operating-system-experiment/Thread.cpp  |  5 ++-
 6 files changed, 73 insertions(+), 3 deletions(-)
 create mode 100644 works/life/operating-system-experiment/MutexAvoidDataRaceDemo.cpp

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/CMakeLists.txt b/works/life/operating-system-experiment/CMakeLists.txt
index 806ec74..139d2ba 100644
--- a/works/life/operating-system-experiment/CMakeLists.txt
+++ b/works/life/operating-system-experiment/CMakeLists.txt
@@ -21,3 +21,6 @@ target_link_libraries(main PRIVATE cru_system)
 
 add_executable(data_race_demo DataRaceDemo.cpp)
 target_link_libraries(data_race_demo PRIVATE cru_system)
+
+add_executable(mutex_avoid_data_race_demo MutexAvoidDataRaceDemo.cpp)
+target_link_libraries(mutex_avoid_data_race_demo PRIVATE cru_system)
diff --git a/works/life/operating-system-experiment/DataRaceDemo.cpp b/works/life/operating-system-experiment/DataRaceDemo.cpp
index 9589eb3..a2f98d9 100644
--- a/works/life/operating-system-experiment/DataRaceDemo.cpp
+++ b/works/life/operating-system-experiment/DataRaceDemo.cpp
@@ -21,7 +21,7 @@ int main() {
   t1.Join();
   t2.Join();
   std::cout << "Answer is " << data << ", which is "
-            << (data == 200000 ? "correct" : "false") << '\n';
+            << (data == 2000000 ? "correct" : "false") << '\n';
 
   return 0;
 }
diff --git a/works/life/operating-system-experiment/Mutex.cpp b/works/life/operating-system-experiment/Mutex.cpp
index 6a91885..b7d0cb6 100644
--- a/works/life/operating-system-experiment/Mutex.cpp
+++ b/works/life/operating-system-experiment/Mutex.cpp
@@ -1,7 +1,6 @@
 #include "Mutex.h"
 
 #include <cassert>
-#include <pthread.h>
 
 #ifndef CRU_WINDOWS
 #include <errno.h>
@@ -10,6 +9,8 @@
 namespace cru {
 Mutex::Mutex() {
 #ifdef CRU_WINDOWS
+  handle_ = CreateMutexW(nullptr, FALSE, nullptr);
+  assert(handle_);
 #else
   mutex_ = std::make_unique<pthread_mutex_t>();
 
@@ -20,16 +21,25 @@ Mutex::Mutex() {
 
 Mutex::Mutex(Mutex &&other)
 #ifdef CRU_WINDOWS
+    : handle_(other.handle_)
 #else
     : mutex_(std::move(other.mutex_))
 #endif
 {
+#ifdef CRU_WINDOWS
+  other.handle_ = nullptr;
+#endif
 }
 
 Mutex &Mutex::operator=(Mutex &&other) {
   if (this != &other) {
     Destroy();
+#ifdef CRU_WINDOWS
+    handle_ = other.handle_;
+    other.handle_ = nullptr;
+#else
     mutex_ = std::move(other.mutex_);
+#endif
   }
   return *this;
 }
@@ -38,6 +48,8 @@ Mutex::~Mutex() { Destroy(); }
 
 void Mutex::Lock() {
 #ifdef CRU_WINDOWS
+  auto c = WaitForSingleObject(handle_, INFINITE);
+  assert(c == WAIT_OBJECT_0);
 #else
   assert(mutex_);
   auto c = pthread_mutex_lock(mutex_.get());
@@ -47,6 +59,9 @@ void Mutex::Lock() {
 
 bool Mutex::TryLock() {
 #ifdef CRU_WINDOWS
+  auto c = WaitForSingleObject(handle_, 0);
+  assert(c == WAIT_OBJECT_0 || c == WAIT_TIMEOUT);
+  return c == WAIT_OBJECT_0 ? true : false;
 #else
   assert(mutex_);
   auto c = pthread_mutex_trylock(mutex_.get());
@@ -57,6 +72,8 @@ bool Mutex::TryLock() {
 
 void Mutex::Unlock() {
 #ifdef CRU_WINDOWS
+  auto c = ReleaseMutex(handle_);
+  assert(c);
 #else
   assert(mutex_);
   auto c = pthread_mutex_unlock(mutex_.get());
@@ -66,6 +83,10 @@ void Mutex::Unlock() {
 
 void Mutex::Destroy() {
 #ifdef CRU_WINDOWS
+  if (handle_ != nullptr) {
+    auto c = CloseHandle(handle_);
+    assert(c);
+  }
 #else
   if (mutex_ != nullptr) {
     auto c = pthread_mutex_destroy(mutex_.get());
diff --git a/works/life/operating-system-experiment/Mutex.h b/works/life/operating-system-experiment/Mutex.h
index 163d9ca..d561f1a 100644
--- a/works/life/operating-system-experiment/Mutex.h
+++ b/works/life/operating-system-experiment/Mutex.h
@@ -35,6 +35,7 @@ private:
 
 private:
 #ifdef CRU_WINDOWS
+  HANDLE handle_;
 #else
   std::unique_ptr<pthread_mutex_t> mutex_;
 #endif
diff --git a/works/life/operating-system-experiment/MutexAvoidDataRaceDemo.cpp b/works/life/operating-system-experiment/MutexAvoidDataRaceDemo.cpp
new file mode 100644
index 0000000..81a7aa1
--- /dev/null
+++ b/works/life/operating-system-experiment/MutexAvoidDataRaceDemo.cpp
@@ -0,0 +1,42 @@
+#include "Mutex.h"
+#include "Thread.h"
+
+#include <iostream>
+
+int main() {
+
+  unsigned data = 0;
+  cru::Mutex mutex;
+  mutex.Lock();
+
+  cru::Thread t1([&data, &mutex] {
+    for (int i = 0; i < 100000; i++) {
+      mutex.Lock();
+      data += 10;
+      //std::cout << "Data is now: " << data << '\n';
+      mutex.Unlock();
+    }
+  });
+
+  cru::Thread t2([&data, &mutex] {
+    for (int i = 0; i < 100000; i++) {
+      mutex.Lock();
+      data += 10;
+      //std::cout << "Data is now: " << data << '\n';
+      mutex.Unlock();
+    }
+  });
+
+  std::cout << "Created thread: " << t1.GetNativeID() << '\n';
+  std::cout << "Created thread: " << t2.GetNativeID() << '\n';
+
+  mutex.Unlock();
+
+  t1.Join();
+  t2.Join();
+
+  std::cout << "Answer is " << data << ", which is "
+            << (data == 2000000 ? "correct" : "false") << '\n';
+
+  return 0;
+}
diff --git a/works/life/operating-system-experiment/Thread.cpp b/works/life/operating-system-experiment/Thread.cpp
index 7e3c784..a5f526d 100644
--- a/works/life/operating-system-experiment/Thread.cpp
+++ b/works/life/operating-system-experiment/Thread.cpp
@@ -112,7 +112,10 @@ void Thread::Destroy() noexcept {
     joined_ = false;
 #ifdef CRU_WINDOWS
     thread_id_ = 0;
-    thread_handle_ = nullptr;
+    if (thread_handle_ != nullptr) {
+      CloseHandle(thread_handle_);
+      thread_handle_ = nullptr;
+    }
 #else
     thread_ = nullptr;
 #endif
-- 
cgit v1.2.3


From bfd0f33af41ac2d5f26d597eac80070911c945a5 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Thu, 10 Jun 2021 11:36:27 +0800
Subject: import(life): ...

---
 works/life/operating-system-experiment/Mutex.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/Mutex.cpp b/works/life/operating-system-experiment/Mutex.cpp
index b7d0cb6..4d360f1 100644
--- a/works/life/operating-system-experiment/Mutex.cpp
+++ b/works/life/operating-system-experiment/Mutex.cpp
@@ -90,7 +90,7 @@ void Mutex::Destroy() {
 #else
   if (mutex_ != nullptr) {
     auto c = pthread_mutex_destroy(mutex_.get());
-    assert(c);
+    assert(c == 0);
     mutex_ = nullptr;
   }
 #endif
-- 
cgit v1.2.3


From 91ec864a9c8e023f9f87d1c079a1cd8024844a7a Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Thu, 10 Jun 2021 11:43:23 +0800
Subject: import(life): ...

---
 works/life/operating-system-experiment/CMakeLists.txt  |  2 +-
 works/life/operating-system-experiment/Interlocked.cpp | 16 ++++++++++++++++
 works/life/operating-system-experiment/Interlocked.hpp | 10 ++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 works/life/operating-system-experiment/Interlocked.cpp
 create mode 100644 works/life/operating-system-experiment/Interlocked.hpp

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/CMakeLists.txt b/works/life/operating-system-experiment/CMakeLists.txt
index 139d2ba..bd50319 100644
--- a/works/life/operating-system-experiment/CMakeLists.txt
+++ b/works/life/operating-system-experiment/CMakeLists.txt
@@ -9,7 +9,7 @@ set(CMAKE_CXX_STANDARD 17)
 
 find_package(fmt CONFIG REQUIRED)
 find_package(Microsoft.GSL CONFIG REQUIRED)
-add_library(cru_system SHARED Thread.cpp Mutex.cpp)
+add_library(cru_system SHARED Thread.cpp Mutex.cpp Interlocked.cpp)
 target_link_libraries(cru_system PUBLIC Microsoft.GSL::GSL fmt::fmt)
 target_compile_definitions(cru_system PUBLIC CRU_EXPORT_API)
 if(UNIX)
diff --git a/works/life/operating-system-experiment/Interlocked.cpp b/works/life/operating-system-experiment/Interlocked.cpp
new file mode 100644
index 0000000..4f224e4
--- /dev/null
+++ b/works/life/operating-system-experiment/Interlocked.cpp
@@ -0,0 +1,16 @@
+#include "Interlocked.hpp"
+
+#ifdef CRU_WINDOWS
+#include <Windows.h>
+#else
+#endif
+
+namespace cru {
+void InterlockedIncrease(volatile long long *v) {
+#ifdef CRU_WINDOWS
+  InterlockedIncrement64(v);
+#else
+
+#endif
+}
+} // namespace cru
diff --git a/works/life/operating-system-experiment/Interlocked.hpp b/works/life/operating-system-experiment/Interlocked.hpp
new file mode 100644
index 0000000..1151e39
--- /dev/null
+++ b/works/life/operating-system-experiment/Interlocked.hpp
@@ -0,0 +1,10 @@
+#ifndef HRADER_INTERLOCKED_H
+#define HRADER_INTERLOCKED_H
+
+#include "Base.h"
+
+namespace cru {
+CRU_API void InterlockedIncrease(volatile long long *v);
+}
+
+#endif
-- 
cgit v1.2.3


From 1ce9ffb961fa2d2f878131bfc6fe38ce9317a401 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Thu, 10 Jun 2021 11:47:14 +0800
Subject: import(life): ...

---
 works/life/operating-system-experiment/Interlocked.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/Interlocked.cpp b/works/life/operating-system-experiment/Interlocked.cpp
index 4f224e4..1c0f638 100644
--- a/works/life/operating-system-experiment/Interlocked.cpp
+++ b/works/life/operating-system-experiment/Interlocked.cpp
@@ -6,11 +6,11 @@
 #endif
 
 namespace cru {
-void InterlockedIncrease(volatile long long *v) {
+void InterlockedAdd(volatile long long *v, long long a) {
 #ifdef CRU_WINDOWS
-  InterlockedIncrement64(v);
+  InterlockedAdd64(v, a);
 #else
-
+  __sync_fetch_and_add(v, a);
 #endif
 }
 } // namespace cru
-- 
cgit v1.2.3


From 06c91dd3a3d17bd1f884c7e322fd7701a95ce7a9 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Thu, 10 Jun 2021 11:48:45 +0800
Subject: import(life): ...

---
 works/life/operating-system-experiment/Interlocked.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/Interlocked.hpp b/works/life/operating-system-experiment/Interlocked.hpp
index 1151e39..aa5dbfc 100644
--- a/works/life/operating-system-experiment/Interlocked.hpp
+++ b/works/life/operating-system-experiment/Interlocked.hpp
@@ -4,7 +4,7 @@
 #include "Base.h"
 
 namespace cru {
-CRU_API void InterlockedIncrease(volatile long long *v);
+CRU_API void InterlockedAdd(volatile long long *v, long long a);
 }
 
 #endif
-- 
cgit v1.2.3


From 5018c2b40009258ed0691cbbb1dcc4d8ac4a809b Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Thu, 10 Jun 2021 11:55:27 +0800
Subject: import(life): ...

---
 .../operating-system-experiment/CMakeLists.txt     |  3 +++
 .../operating-system-experiment/Interlocked.cpp    |  2 +-
 .../operating-system-experiment/Interlocked.hpp    |  2 +-
 .../InterlockedAvoidDataRaceDemo.cpp               | 28 ++++++++++++++++++++++
 works/life/operating-system-experiment/Thread.cpp  | 18 ++++++++++++--
 works/life/operating-system-experiment/Thread.h    | 12 ++--------
 6 files changed, 51 insertions(+), 14 deletions(-)
 create mode 100644 works/life/operating-system-experiment/InterlockedAvoidDataRaceDemo.cpp

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/CMakeLists.txt b/works/life/operating-system-experiment/CMakeLists.txt
index bd50319..8b4617f 100644
--- a/works/life/operating-system-experiment/CMakeLists.txt
+++ b/works/life/operating-system-experiment/CMakeLists.txt
@@ -24,3 +24,6 @@ target_link_libraries(data_race_demo PRIVATE cru_system)
 
 add_executable(mutex_avoid_data_race_demo MutexAvoidDataRaceDemo.cpp)
 target_link_libraries(mutex_avoid_data_race_demo PRIVATE cru_system)
+
+add_executable(interlocked_avoid_data_race_demo InterlockedAvoidDataRaceDemo.cpp)
+target_link_libraries(interlocked_avoid_data_race_demo PRIVATE cru_system)
diff --git a/works/life/operating-system-experiment/Interlocked.cpp b/works/life/operating-system-experiment/Interlocked.cpp
index 1c0f638..7fc8c6b 100644
--- a/works/life/operating-system-experiment/Interlocked.cpp
+++ b/works/life/operating-system-experiment/Interlocked.cpp
@@ -6,7 +6,7 @@
 #endif
 
 namespace cru {
-void InterlockedAdd(volatile long long *v, long long a) {
+void CruInterlockedAdd(volatile long long *v, long long a) {
 #ifdef CRU_WINDOWS
   InterlockedAdd64(v, a);
 #else
diff --git a/works/life/operating-system-experiment/Interlocked.hpp b/works/life/operating-system-experiment/Interlocked.hpp
index aa5dbfc..7e09b60 100644
--- a/works/life/operating-system-experiment/Interlocked.hpp
+++ b/works/life/operating-system-experiment/Interlocked.hpp
@@ -4,7 +4,7 @@
 #include "Base.h"
 
 namespace cru {
-CRU_API void InterlockedAdd(volatile long long *v, long long a);
+CRU_API void CruInterlockedAdd(volatile long long *v, long long a);
 }
 
 #endif
diff --git a/works/life/operating-system-experiment/InterlockedAvoidDataRaceDemo.cpp b/works/life/operating-system-experiment/InterlockedAvoidDataRaceDemo.cpp
new file mode 100644
index 0000000..91d6d50
--- /dev/null
+++ b/works/life/operating-system-experiment/InterlockedAvoidDataRaceDemo.cpp
@@ -0,0 +1,28 @@
+#include "Interlocked.hpp"
+#include "Thread.h"
+
+#include <iostream>
+
+int main() {
+  volatile long long data = 0;
+
+  cru::Thread t1([&data] {
+    for (int i = 0; i < 100000; i++)
+      cru::CruInterlockedAdd(&data, 10);
+  });
+
+  cru::Thread t2([&data] {
+    for (int i = 0; i < 100000; i++)
+      cru::CruInterlockedAdd(&data, 10);
+  });
+
+  std::cout << "Created thread: " << t1.GetNativeID() << '\n';
+  std::cout << "Created thread: " << t2.GetNativeID() << '\n';
+
+  t1.Join();
+  t2.Join();
+  std::cout << "Answer is " << data << ", which is "
+            << (data == 2000000 ? "correct" : "false") << '\n';
+
+  return 0;
+}
diff --git a/works/life/operating-system-experiment/Thread.cpp b/works/life/operating-system-experiment/Thread.cpp
index a5f526d..657c69f 100644
--- a/works/life/operating-system-experiment/Thread.cpp
+++ b/works/life/operating-system-experiment/Thread.cpp
@@ -122,7 +122,7 @@ void Thread::Destroy() noexcept {
   }
 }
 
-namespace details {
+namespace {
 #ifdef CRU_WINDOWS
 DWORD WINAPI ThreadProc(_In_ LPVOID lpParameter) {
   auto p = static_cast<std::function<void()> *>(lpParameter);
@@ -139,5 +139,19 @@ void *ThreadProc(void *data) {
 }
 
 #endif
-} // namespace details
+} // namespace
+
+void Thread::CreateThread(std::function<void()> *proc) {
+#ifdef CRU_WINDOWS
+  thread_handle_ = ::CreateThread(nullptr, 0, ThreadProc,
+                                  static_cast<void *>(proc), 0, &thread_id_);
+  assert(thread_handle_);
+#else
+  thread_.reset(new pthread_t());
+  auto c = pthread_create(thread_.get(), nullptr, ThreadProc,
+                          static_cast<void *>(proc));
+  assert(c == 0);
+#endif
+};
+
 } // namespace cru
\ No newline at end of file
diff --git a/works/life/operating-system-experiment/Thread.h b/works/life/operating-system-experiment/Thread.h
index 56fdcb0..735407c 100644
--- a/works/life/operating-system-experiment/Thread.h
+++ b/works/life/operating-system-experiment/Thread.h
@@ -52,6 +52,7 @@ public:
 
 private:
   void Destroy() noexcept;
+  void CreateThread(std::function<void()> *proc);
 
 private:
   bool detached_ = false;
@@ -81,16 +82,7 @@ Thread::Thread(Fn &&process, Args &&...args) {
         std::apply(process, std::move(args));
       });
 
-#ifdef CRU_WINDOWS
-  thread_handle_ = ::CreateThread(nullptr, 0, &::cru::details::ThreadProc,
-                                  static_cast<void *>(p), 0, &thread_id_);
-  assert(thread_handle_);
-#else
-  thread_.reset(new pthread_t());
-  auto c = pthread_create(thread_.get(), nullptr, details::ThreadProc,
-                          static_cast<void *>(p));
-  assert(c == 0);
-#endif
+  CreateThread(p);
 };
 } // namespace cru
 
-- 
cgit v1.2.3


From 0380cd595ee05773f78751aa7f2952b6ea105f7c Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Fri, 11 Jun 2021 10:43:00 +0800
Subject: import(life): ...

---
 .../operating-system-experiment/CMakeLists.txt     |  6 +-
 .../life/operating-system-experiment/Semaphore.cpp | 78 ++++++++++++++++++++++
 works/life/operating-system-experiment/Semaphore.h | 46 +++++++++++++
 .../SemaphoreAvoidDataRaceDemo.cpp                 | 36 ++++++++++
 4 files changed, 165 insertions(+), 1 deletion(-)
 create mode 100644 works/life/operating-system-experiment/Semaphore.cpp
 create mode 100644 works/life/operating-system-experiment/Semaphore.h
 create mode 100644 works/life/operating-system-experiment/SemaphoreAvoidDataRaceDemo.cpp

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/CMakeLists.txt b/works/life/operating-system-experiment/CMakeLists.txt
index 8b4617f..c8afc24 100644
--- a/works/life/operating-system-experiment/CMakeLists.txt
+++ b/works/life/operating-system-experiment/CMakeLists.txt
@@ -9,7 +9,7 @@ set(CMAKE_CXX_STANDARD 17)
 
 find_package(fmt CONFIG REQUIRED)
 find_package(Microsoft.GSL CONFIG REQUIRED)
-add_library(cru_system SHARED Thread.cpp Mutex.cpp Interlocked.cpp)
+add_library(cru_system SHARED Thread.cpp Mutex.cpp Interlocked.cpp Semaphore.cpp)
 target_link_libraries(cru_system PUBLIC Microsoft.GSL::GSL fmt::fmt)
 target_compile_definitions(cru_system PUBLIC CRU_EXPORT_API)
 if(UNIX)
@@ -27,3 +27,7 @@ target_link_libraries(mutex_avoid_data_race_demo PRIVATE cru_system)
 
 add_executable(interlocked_avoid_data_race_demo InterlockedAvoidDataRaceDemo.cpp)
 target_link_libraries(interlocked_avoid_data_race_demo PRIVATE cru_system)
+
+add_executable(semaphore_avoid_data_race_demo SemaphoreAvoidDataRaceDemo.cpp)
+target_link_libraries(semaphore_avoid_data_race_demo PRIVATE cru_system)
+
diff --git a/works/life/operating-system-experiment/Semaphore.cpp b/works/life/operating-system-experiment/Semaphore.cpp
new file mode 100644
index 0000000..e8221fd
--- /dev/null
+++ b/works/life/operating-system-experiment/Semaphore.cpp
@@ -0,0 +1,78 @@
+#include "Semaphore.h"
+
+#include <cassert>
+
+#ifndef CRU_WINDOWS
+#include <errno.h>
+#endif
+
+namespace cru {
+Semaphore::Semaphore(unsigned init_value) {
+#ifdef CRU_WINDOWS
+#else
+  semaphore_ = std::make_unique<sem_t>();
+  auto c = sem_init(semaphore_.get(), 0, init_value);
+  assert(c == 0);
+#endif
+}
+
+Semaphore::Semaphore(Semaphore &&other)
+#ifdef CRU_WINDOWS
+#else
+    : semaphore_(std::move(other.semaphore_))
+#endif
+{
+}
+
+Semaphore &Semaphore::operator=(Semaphore &&other) {
+  if (this != &other) {
+    Destroy();
+#ifdef CRU_WINDOWS
+#else
+    semaphore_ = std::move(other.semaphore_);
+#endif
+  }
+  return *this;
+}
+
+Semaphore::~Semaphore() { Destroy(); }
+
+void Semaphore::P() { Acquire(); }
+void Semaphore::V() { Release(); }
+
+void Semaphore::Acquire() {
+#ifdef CRU_WINDOWS
+#else
+  auto c = sem_wait(semaphore_.get());
+  assert(c == 0);
+#endif
+}
+
+bool Semaphore::TryAcquire() {
+#ifdef CRU_WINDOWS
+#else
+  auto c = sem_trywait(semaphore_.get());
+  assert((c == 0) || (c == -1 && errno == EAGAIN));
+  return c == 0 ? true : false;
+#endif
+}
+
+void Semaphore::Release() {
+#ifdef CRU_WINDOWS
+#else
+  auto c = sem_post(semaphore_.get());
+  assert(c == 0);
+#endif
+}
+
+void Semaphore::Destroy() {
+#ifdef CRU_WINDOWS
+#else
+  if (semaphore_ != nullptr) {
+    auto c = sem_destroy(semaphore_.get());
+    assert(c == 0);
+    semaphore_ = nullptr;
+  }
+#endif
+}
+} // namespace cru
\ No newline at end of file
diff --git a/works/life/operating-system-experiment/Semaphore.h b/works/life/operating-system-experiment/Semaphore.h
new file mode 100644
index 0000000..1d49b60
--- /dev/null
+++ b/works/life/operating-system-experiment/Semaphore.h
@@ -0,0 +1,46 @@
+#ifndef HEADER_SEMAPHORE_H
+#define HEADER_SEMAPHORE_H
+
+#include "Base.h"
+
+#include <memory>
+
+#ifdef CRU_WINDOWS
+#include <Windows.h>
+#else
+#include <semaphore.h>
+#endif
+
+namespace cru {
+class CRU_API Semaphore {
+public:
+  explicit Semaphore(unsigned init_value = 1);
+
+  Semaphore(const Semaphore &other) = delete;
+  Semaphore &operator=(const Semaphore &other) = delete;
+
+  Semaphore(Semaphore &&other);
+  Semaphore &operator=(Semaphore &&other);
+
+  ~Semaphore();
+
+public:
+  void P();
+  void V();
+
+  void Acquire();
+  bool TryAcquire();
+  void Release();
+
+private:
+  void Destroy();
+
+private:
+#ifdef CRU_WINDOWS
+#else
+  std::unique_ptr<sem_t> semaphore_;
+#endif
+};
+} // namespace cru
+
+#endif
\ No newline at end of file
diff --git a/works/life/operating-system-experiment/SemaphoreAvoidDataRaceDemo.cpp b/works/life/operating-system-experiment/SemaphoreAvoidDataRaceDemo.cpp
new file mode 100644
index 0000000..0068082
--- /dev/null
+++ b/works/life/operating-system-experiment/SemaphoreAvoidDataRaceDemo.cpp
@@ -0,0 +1,36 @@
+#include "Semaphore.h"
+#include "Thread.h"
+
+#include <iostream>
+
+int main() {
+  unsigned data = 0;
+
+  cru::Semaphore semaphore;
+
+  cru::Thread t1([&data, &semaphore] {
+    for (int i = 0; i < 100000; i++) {
+      semaphore.P();
+      data += 10;
+      semaphore.V();
+    }
+  });
+
+  cru::Thread t2([&data, &semaphore] {
+    for (int i = 0; i < 100000; i++) {
+      semaphore.P();
+      data += 10;
+      semaphore.V();
+    }
+  });
+
+  std::cout << "Created thread: " << t1.GetNativeID() << '\n';
+  std::cout << "Created thread: " << t2.GetNativeID() << '\n';
+
+  t1.Join();
+  t2.Join();
+  std::cout << "Answer is " << data << ", which is "
+            << (data == 2000000 ? "correct" : "false") << '\n';
+
+  return 0;
+}
-- 
cgit v1.2.3


From fabd9692c49bad9f4f2858315f2a16501ad45d21 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Fri, 11 Jun 2021 11:02:41 +0800
Subject: import(life): ...

---
 works/life/operating-system-experiment/Mutex.cpp     |  1 +
 works/life/operating-system-experiment/Semaphore.cpp | 20 ++++++++++++++++++++
 works/life/operating-system-experiment/Semaphore.h   |  1 +
 works/life/operating-system-experiment/Thread.cpp    |  3 ++-
 4 files changed, 24 insertions(+), 1 deletion(-)

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/Mutex.cpp b/works/life/operating-system-experiment/Mutex.cpp
index 4d360f1..8acfdc5 100644
--- a/works/life/operating-system-experiment/Mutex.cpp
+++ b/works/life/operating-system-experiment/Mutex.cpp
@@ -86,6 +86,7 @@ void Mutex::Destroy() {
   if (handle_ != nullptr) {
     auto c = CloseHandle(handle_);
     assert(c);
+    handle_ = nullptr;
   }
 #else
   if (mutex_ != nullptr) {
diff --git a/works/life/operating-system-experiment/Semaphore.cpp b/works/life/operating-system-experiment/Semaphore.cpp
index e8221fd..aceef4d 100644
--- a/works/life/operating-system-experiment/Semaphore.cpp
+++ b/works/life/operating-system-experiment/Semaphore.cpp
@@ -9,6 +9,8 @@
 namespace cru {
 Semaphore::Semaphore(unsigned init_value) {
 #ifdef CRU_WINDOWS
+  handle_ = CreateSemaphoreW(nullptr, init_value, 100, nullptr);
+  assert(handle_);
 #else
   semaphore_ = std::make_unique<sem_t>();
   auto c = sem_init(semaphore_.get(), 0, init_value);
@@ -18,16 +20,22 @@ Semaphore::Semaphore(unsigned init_value) {
 
 Semaphore::Semaphore(Semaphore &&other)
 #ifdef CRU_WINDOWS
+    : handle_(other.handle_)
 #else
     : semaphore_(std::move(other.semaphore_))
 #endif
 {
+#ifdef CRU_WINDOWS
+  other.handle_ = nullptr;
+#endif
 }
 
 Semaphore &Semaphore::operator=(Semaphore &&other) {
   if (this != &other) {
     Destroy();
 #ifdef CRU_WINDOWS
+    handle_ = other.handle_;
+    other.handle_ = nullptr;
 #else
     semaphore_ = std::move(other.semaphore_);
 #endif
@@ -42,6 +50,8 @@ void Semaphore::V() { Release(); }
 
 void Semaphore::Acquire() {
 #ifdef CRU_WINDOWS
+  auto c = WaitForSingleObject(handle_, INFINITE);
+  assert(c == WAIT_OBJECT_0);
 #else
   auto c = sem_wait(semaphore_.get());
   assert(c == 0);
@@ -50,6 +60,9 @@ void Semaphore::Acquire() {
 
 bool Semaphore::TryAcquire() {
 #ifdef CRU_WINDOWS
+  auto c = WaitForSingleObject(handle_, 0);
+  assert(c == WAIT_OBJECT_0 || c == WAIT_TIMEOUT);
+  return c == WAIT_OBJECT_0 ? true : false;
 #else
   auto c = sem_trywait(semaphore_.get());
   assert((c == 0) || (c == -1 && errno == EAGAIN));
@@ -59,6 +72,8 @@ bool Semaphore::TryAcquire() {
 
 void Semaphore::Release() {
 #ifdef CRU_WINDOWS
+  auto c = ReleaseSemaphore(handle_, 1, nullptr);
+  assert(c);
 #else
   auto c = sem_post(semaphore_.get());
   assert(c == 0);
@@ -67,6 +82,11 @@ void Semaphore::Release() {
 
 void Semaphore::Destroy() {
 #ifdef CRU_WINDOWS
+  if (handle_ != nullptr) {
+    auto c = CloseHandle(handle_);
+    assert(c);
+    handle_ = nullptr;
+  }
 #else
   if (semaphore_ != nullptr) {
     auto c = sem_destroy(semaphore_.get());
diff --git a/works/life/operating-system-experiment/Semaphore.h b/works/life/operating-system-experiment/Semaphore.h
index 1d49b60..430c036 100644
--- a/works/life/operating-system-experiment/Semaphore.h
+++ b/works/life/operating-system-experiment/Semaphore.h
@@ -37,6 +37,7 @@ private:
 
 private:
 #ifdef CRU_WINDOWS
+  HANDLE handle_ = nullptr;
 #else
   std::unique_ptr<sem_t> semaphore_;
 #endif
diff --git a/works/life/operating-system-experiment/Thread.cpp b/works/life/operating-system-experiment/Thread.cpp
index 657c69f..0bc4c18 100644
--- a/works/life/operating-system-experiment/Thread.cpp
+++ b/works/life/operating-system-experiment/Thread.cpp
@@ -113,7 +113,8 @@ void Thread::Destroy() noexcept {
 #ifdef CRU_WINDOWS
     thread_id_ = 0;
     if (thread_handle_ != nullptr) {
-      CloseHandle(thread_handle_);
+      auto c = CloseHandle(thread_handle_);
+      assert(c);
       thread_handle_ = nullptr;
     }
 #else
-- 
cgit v1.2.3


From e9cfa972d7ffd09584b678b42cb60bf50b8efa92 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Fri, 11 Jun 2021 11:24:08 +0800
Subject: import(life): ...

---
 .../operating-system-experiment/CMakeLists.txt     |  2 +
 .../ParallelCalculationDemo.cpp                    | 73 ++++++++++++++++++++++
 2 files changed, 75 insertions(+)
 create mode 100644 works/life/operating-system-experiment/ParallelCalculationDemo.cpp

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/CMakeLists.txt b/works/life/operating-system-experiment/CMakeLists.txt
index c8afc24..5671b4a 100644
--- a/works/life/operating-system-experiment/CMakeLists.txt
+++ b/works/life/operating-system-experiment/CMakeLists.txt
@@ -31,3 +31,5 @@ target_link_libraries(interlocked_avoid_data_race_demo PRIVATE cru_system)
 add_executable(semaphore_avoid_data_race_demo SemaphoreAvoidDataRaceDemo.cpp)
 target_link_libraries(semaphore_avoid_data_race_demo PRIVATE cru_system)
 
+add_executable(parallel_calculation_demo ParallelCalculationDemo.cpp)
+target_link_libraries(parallel_calculation_demo PRIVATE cru_system)
diff --git a/works/life/operating-system-experiment/ParallelCalculationDemo.cpp b/works/life/operating-system-experiment/ParallelCalculationDemo.cpp
new file mode 100644
index 0000000..31ff2bf
--- /dev/null
+++ b/works/life/operating-system-experiment/ParallelCalculationDemo.cpp
@@ -0,0 +1,73 @@
+#include "Thread.h"
+
+#include <iostream>
+
+const long long N = 1e9;
+
+int main(int argc, char **argv) {
+  int thread_number;
+  if (argc == 1) {
+    thread_number = 1;
+  } else if (argc == 2) {
+    thread_number = std::atoi(argv[1]);
+    if (thread_number <= 0) {
+      std::cerr << "Argument must be a positive integer.\n";
+    }
+  } else {
+    std::cerr << "Too many arguments.\n";
+  }
+
+  std::cout << "Use " << thread_number << " threads to calculate sum of 1-" << N
+            << ".\n";
+
+  if (thread_number == 1) {
+    long long sum = 0;
+    for (long long i = 1; i <= 1e9; i++) {
+      sum += i;
+    }
+    std::cout << "Sum of 1-" << N << " is " << sum << '\n';
+  } else {
+    std::vector<cru::Thread> threads(thread_number);
+    std::vector<long long> partial_sum(thread_number);
+
+    long long step = N / thread_number;
+
+    for (int i = 0; i < thread_number; i++) {
+      long long start = step * i;
+      long long end = step * (i + 1);
+
+      long long &ps = partial_sum[i];
+
+      if (i == thread_number - 1) {
+        threads[i] = cru::Thread([&ps, start] {
+          long long sum = 0;
+          for (long long j = start; j <= 1e9; j++) {
+            sum += j;
+          }
+          ps = sum;
+        });
+      } else {
+        threads[i] = cru::Thread([&ps, start, end] {
+          long long sum = 0;
+          for (int j = start; j < end; j++) {
+            sum += j;
+          }
+          ps = sum;
+        });
+      }
+    }
+
+    for (auto &thread : threads) {
+      thread.Join();
+    }
+
+    long long sum = 0;
+    for (auto ps : partial_sum) {
+      sum += ps;
+    }
+
+    std::cout << "Sum of 1-" << N << " is " << sum << '\n';
+  }
+
+  return 0;
+}
-- 
cgit v1.2.3


From 2c7ceca3e58543c36098fd46de711d9cd80a4d12 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Fri, 11 Jun 2021 11:34:16 +0800
Subject: import(life): ...

---
 works/life/operating-system-experiment/ParallelCalculationDemo.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/ParallelCalculationDemo.cpp b/works/life/operating-system-experiment/ParallelCalculationDemo.cpp
index 31ff2bf..7340da8 100644
--- a/works/life/operating-system-experiment/ParallelCalculationDemo.cpp
+++ b/works/life/operating-system-experiment/ParallelCalculationDemo.cpp
@@ -41,7 +41,7 @@ int main(int argc, char **argv) {
       if (i == thread_number - 1) {
         threads[i] = cru::Thread([&ps, start] {
           long long sum = 0;
-          for (long long j = start; j <= 1e9; j++) {
+          for (long long j = start; j <= N; j++) {
             sum += j;
           }
           ps = sum;
-- 
cgit v1.2.3


From dc0dfeec23158268268da5a16364abb1f0de5a06 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Sat, 12 Jun 2021 23:20:15 +0800
Subject: import(life): ...

---
 .../operating-system-experiment/CMakeLists.txt     |  2 ++
 .../DeadLockDetectionDemo.cpp                      | 25 ++++++++++++++++++++++
 .../ParallelCalculationDemo.cpp                    |  2 ++
 works/life/operating-system-experiment/Thread.h    |  8 -------
 4 files changed, 29 insertions(+), 8 deletions(-)
 create mode 100644 works/life/operating-system-experiment/DeadLockDetectionDemo.cpp

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/CMakeLists.txt b/works/life/operating-system-experiment/CMakeLists.txt
index 5671b4a..79fe786 100644
--- a/works/life/operating-system-experiment/CMakeLists.txt
+++ b/works/life/operating-system-experiment/CMakeLists.txt
@@ -33,3 +33,5 @@ target_link_libraries(semaphore_avoid_data_race_demo PRIVATE cru_system)
 
 add_executable(parallel_calculation_demo ParallelCalculationDemo.cpp)
 target_link_libraries(parallel_calculation_demo PRIVATE cru_system)
+
+add_executable(dead_lock_detection_demo DeadLockDetectionDemo.cpp)
diff --git a/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp b/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp
new file mode 100644
index 0000000..b22549e
--- /dev/null
+++ b/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp
@@ -0,0 +1,25 @@
+#include <fstream>
+#include <iostream>
+#include <vector>
+
+int main() {
+  std::vector<int> ns;
+
+  while (!std::cin.eof() || std::cin) {
+    int n;
+    std::cin >> n;
+    ns.push_back(n);
+  }
+
+  if (!std::cin.eof()) {
+    std::cerr << "Failed to parse input.\n";
+    return -1;
+  }
+
+  if (ns.size() % 2 != 0) {
+    std::cerr << "Input integer number must be even.\n";
+    return -1;
+  }
+
+  
+}
diff --git a/works/life/operating-system-experiment/ParallelCalculationDemo.cpp b/works/life/operating-system-experiment/ParallelCalculationDemo.cpp
index 7340da8..0174c55 100644
--- a/works/life/operating-system-experiment/ParallelCalculationDemo.cpp
+++ b/works/life/operating-system-experiment/ParallelCalculationDemo.cpp
@@ -12,9 +12,11 @@ int main(int argc, char **argv) {
     thread_number = std::atoi(argv[1]);
     if (thread_number <= 0) {
       std::cerr << "Argument must be a positive integer.\n";
+      return -1;
     }
   } else {
     std::cerr << "Too many arguments.\n";
+    return -1;
   }
 
   std::cout << "Use " << thread_number << " threads to calculate sum of 1-" << N
diff --git a/works/life/operating-system-experiment/Thread.h b/works/life/operating-system-experiment/Thread.h
index 735407c..4ad1ef4 100644
--- a/works/life/operating-system-experiment/Thread.h
+++ b/works/life/operating-system-experiment/Thread.h
@@ -66,14 +66,6 @@ private:
 #endif
 };
 
-namespace details {
-#ifdef CRU_WINDOWS
-CRU_API DWORD WINAPI ThreadProc(_In_ LPVOID lpParameter);
-#else
-void *ThreadProc(void *data);
-#endif
-} // namespace details
-
 template <typename Fn, typename... Args>
 Thread::Thread(Fn &&process, Args &&...args) {
   std::tuple<std::decay_t<Args>...> a{std::forward<Args>(args)...};
-- 
cgit v1.2.3


From 60fb578a0202d354b2fdc5cdf86c04fb9d62c729 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Mon, 14 Jun 2021 18:38:04 +0800
Subject: import(life): ...

---
 .../DeadLockDetectionDemo.cpp                      | 89 +++++++++++++++++++++-
 .../DeadLockTestData1.txt                          |  4 +
 .../DeadLockTestData2.txt                          |  4 +
 .../DeadLockTestData3.txt                          |  6 ++
 .../DeadLockTestData4.txt                          |  9 +++
 5 files changed, 108 insertions(+), 4 deletions(-)
 create mode 100644 works/life/operating-system-experiment/DeadLockTestData1.txt
 create mode 100644 works/life/operating-system-experiment/DeadLockTestData2.txt
 create mode 100644 works/life/operating-system-experiment/DeadLockTestData3.txt
 create mode 100644 works/life/operating-system-experiment/DeadLockTestData4.txt

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp b/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp
index b22549e..e043161 100644
--- a/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp
+++ b/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp
@@ -1,14 +1,66 @@
-#include <fstream>
 #include <iostream>
+#include <unordered_map>
+#include <unordered_set>
 #include <vector>
 
+const int LOCK_START_INDEX = 10000;
+
+struct Node {
+  int id;
+};
+
+bool operator==(const Node &left, const Node &right) {
+  return left.id == right.id;
+}
+
+template <> struct std::hash<Node> {
+  std::size_t operator()(const Node &node) const {
+    return std::hash<int>{}(node.id);
+  }
+};
+
+std::ostream &operator<<(std::ostream &left, const Node &right) {
+  left << (right.id > LOCK_START_INDEX ? "lock" : "process") << ' '
+       << (right.id > LOCK_START_INDEX ? right.id - LOCK_START_INDEX
+                                       : right.id);
+  return left;
+}
+
+bool dfs(
+    const Node *root,
+    std::unordered_map<const Node *, std::unordered_set<const Node *>> &edges,
+    std::unordered_map<const Node *, bool> &visited) {
+
+  if (visited[root]) {
+    std::cout << "Ohhhhhh, it is already visited!\n";
+    return true;
+  }
+
+  visited[root] = true;
+  auto r = edges.find(root);
+  if (r != edges.cend())
+    for (auto n : r->second) {
+      std::cout << "from " << *root << " go to " << *n << "\n";
+      if (dfs(n, edges, visited))
+        return true;
+      std::cout << "from " << *n << " back to " << *root << "\n";
+    }
+
+  edges.erase(root);
+  return false;
+}
+
+// 1 10001 -> process 1 is waiting for lock 10001
+// 10001 1 -> lock 10001 is owned by process 1
+
 int main() {
   std::vector<int> ns;
 
-  while (!std::cin.eof() || std::cin) {
+  while (std::cin) {
     int n;
     std::cin >> n;
-    ns.push_back(n);
+    if (std::cin)
+      ns.push_back(n);
   }
 
   if (!std::cin.eof()) {
@@ -21,5 +73,34 @@ int main() {
     return -1;
   }
 
-  
+  std::unordered_set<Node> nodes;
+  std::unordered_map<const Node *, std::unordered_set<const Node *>> edges;
+
+  for (int i = 0; i < ns.size(); i += 2) {
+    int p = ns[i];
+    int l = ns[i + 1];
+    auto r1 = nodes.insert({p});
+    auto r2 = nodes.insert({l});
+    edges[&(*r1.first)].insert(&(*r2.first));
+  }
+
+  bool h = false;
+
+  while (!edges.empty()) {
+    auto n = edges.cbegin()->first;
+    std::unordered_map<const Node *, bool> visited;
+    std::cout << "Begin to detect child graph containing '" << *n << "'.\n";
+    if (dfs(n, edges, visited)) {
+      h = true;
+      break;
+    }
+  }
+
+  if (h) {
+    std::cout << "Cycle, aka dead lock, detected.\n";
+  } else {
+    std::cout << "You are free of dead lock!!!\n";
+  }
+
+  return 0;
 }
diff --git a/works/life/operating-system-experiment/DeadLockTestData1.txt b/works/life/operating-system-experiment/DeadLockTestData1.txt
new file mode 100644
index 0000000..0c8dd14
--- /dev/null
+++ b/works/life/operating-system-experiment/DeadLockTestData1.txt
@@ -0,0 +1,4 @@
+1 10001
+2 10001
+3 10001
+4 10001
diff --git a/works/life/operating-system-experiment/DeadLockTestData2.txt b/works/life/operating-system-experiment/DeadLockTestData2.txt
new file mode 100644
index 0000000..d632f2a
--- /dev/null
+++ b/works/life/operating-system-experiment/DeadLockTestData2.txt
@@ -0,0 +1,4 @@
+10001 1
+1 10002
+2 10001
+10002 2
diff --git a/works/life/operating-system-experiment/DeadLockTestData3.txt b/works/life/operating-system-experiment/DeadLockTestData3.txt
new file mode 100644
index 0000000..1e1692d
--- /dev/null
+++ b/works/life/operating-system-experiment/DeadLockTestData3.txt
@@ -0,0 +1,6 @@
+1 10001
+10001 2
+2 10002
+10002 3
+3 10003
+10003 1
diff --git a/works/life/operating-system-experiment/DeadLockTestData4.txt b/works/life/operating-system-experiment/DeadLockTestData4.txt
new file mode 100644
index 0000000..d124102
--- /dev/null
+++ b/works/life/operating-system-experiment/DeadLockTestData4.txt
@@ -0,0 +1,9 @@
+1 10001
+2 10001
+3 10002
+3 10004
+10001 3
+4 10001
+4 10005
+10004 5
+10005 5
-- 
cgit v1.2.3


From 213363383b5864d236cfce711920f76a2450de07 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Wed, 16 Jun 2021 20:18:19 +0800
Subject: import(life): ...

---
 .../operating-system-experiment/DeadLockDetectionDemo.cpp   | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

(limited to 'works/life/operating-system-experiment')

diff --git a/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp b/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp
index e043161..bea2b43 100644
--- a/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp
+++ b/works/life/operating-system-experiment/DeadLockDetectionDemo.cpp
@@ -1,3 +1,13 @@
+// Demo使用方法：
+// 本程序采用标准C++11代码写成，请使用支持C++11的编译器编译。
+//
+// 程序接受的输入为n个整数对，其中1-10000表示进程，10001及以上表示锁，顺序很重要：
+// 1 10001 -> process 1 is acquiring or waiting for lock 1
+// 10001 1 -> lock 1 is owned by process 1
+//
+// 建议采用重定向输入至文件的方式输入，提供4个典型情况的测试数据。
+//
+
 #include <iostream>
 #include <unordered_map>
 #include <unordered_set>
@@ -50,9 +60,6 @@ bool dfs(
   return false;
 }
 
-// 1 10001 -> process 1 is waiting for lock 10001
-// 10001 1 -> lock 10001 is owned by process 1
-
 int main() {
   std::vector<int> ns;
 
-- 
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