Added futex, posix shared memory and shared futex

README.md

@@ -1,6 +1,5 @@
 # cpputils
-
-[![Build Status](https://travis-ci.org/yangosoft/cpputils.svg?branch=master)](https://travis-ci.org/yangosoft/cpputils)
+![cpputils workflow](https://github.com/yangosoft/cpputils/actions/workflows/cpp.yml/badge.svg)
 
 C++14 utilites 
 
@@ -15,6 +14,8 @@ C++14 utilites
 * TCP socket server
 * BTree
 * Colors: RGB and LAB color converters and distance calculation
+* Futex and shared memory futex implementation based on [Eli Bendersky Mutex https://eli.thegreenplace.net/2018/basics-of-futexes/](https://eli.thegreenplace.net/2018/basics-of-futexes/) implementation of the [Ulrich Drepper's Futexes are Tricky paper](https://www.akkadia.org/drepper/futex.pdf)
+* Shared memory wrapper for POSIX
 
 Check examples folder and build them after install CppUtils.
 

src/CMakeLists.txt

@@ -1,18 +1,20 @@
-cmake_minimum_required(VERSION 3.4)
+cmake_minimum_required(VERSION 3.17)
 set (CppUtils_VERSION_MAJOR 0)
 set (CppUtils_VERSION_MINOR 1)
 project(CppUtilsLibs VERSION ${CppUtils_VERSION_MAJOR}.${CppUtils_VERSION_MINOR} LANGUAGES CXX)
 
-set(CMAKE_CXX_STANDARD 14)
+# set(CMAKE_C_COMPILER /usr/bin/gcc-12)
+# set(CMAKE_CXX_COMPILER "/usr/bin/g++-12")
+set(CMAKE_CXX_STANDARD 23)
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wsign-promo -Wnon-virtual-dtor -Wctor-dtor-privacy -Woverloaded-virtual -Wold-style-cast -Wpointer-arith -Wshadow -Wunused -Wuninitialized -Winit-self -Wdeprecated -Wfloat-equal")
-set(CMAKE_CXX_EXTENSIONS OFF)
-set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+set(ENABLE_LINUX ON)
 
 
 
 
-set(ENABLE_TEST OFF CACHE BOOL "Enable Google Test")
+set(ENABLE_TEST ON CACHE BOOL "Enable Google Test")
 set(ENABLE_GNUTLS OFF CACHE BOOL "Enable GNUTLS link")
 
 if( NOT CMAKE_BUILD_TYPE )
@@ -21,6 +23,15 @@ MinSizeRel."  FORCE )
 endif()
 
 if( ENABLE_TEST )
+    include(CTest)
+    include(FetchContent)
+    FetchContent_Declare(
+      googletest
+      URL https://github.com/google/googletest/archive/03597a01ee50ed33e9dfd640b249b4be3799d395.zip
+    )
+    # For Windows: Prevent overriding the parent project's compiler/linker settings
+    set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+    FetchContent_MakeAvailable(googletest)
     message("Unit test enabled")
     enable_testing()
 endif()
@@ -37,6 +48,10 @@ add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/graphs)
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/tree)
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/misc/colors)
 
+if (ENABLE_LINUX)
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/linux)
+endif()
+
 #add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/namedpipes)
 
 #add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/example/tcpsocket)

src/abstractfactory/test/CMakeLists.txt

@@ -1,12 +1,12 @@
 project(AbstractFactoryTest)
-cmake_minimum_required(VERSION 2.8)
+cmake_minimum_required(VERSION 3.14)
+
 
-set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pthread")
 
 
 enable_testing()
-find_package(GTest REQUIRED)
+include(GoogleTest)
 
 
 if(NOT TARGET CppUtils::AbstractFactory)
@@ -21,7 +21,7 @@ file(GLOB SRCS ${CMAKE_CURRENT_SOURCE_DIR}/test/src/*.cpp)
 
 add_executable(Test_abstractfactory ${SRCS})
 
-target_link_libraries(Test_abstractfactory PRIVATE ${GTEST_BOTH_LIBRARIES})
+target_link_libraries(Test_abstractfactory PRIVATE  GTest::gtest_main)
 
 add_test(FactoryTests2 Test_abstractfactory --gtest_output=xml)
 

src/example/tcpepollserver/CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.8)
 project(TcpEpollServerExample)
 
 
-set(CMAKE_CXX_STANDARD 14)
+
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pthread")
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 

src/example/tcpsecuresocket/CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.8)
 project(TcpSecureExample)
 
 
-set(CMAKE_CXX_STANDARD 14)
+
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pthread")
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 

src/example/tcpsocket/CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.8)
 project(TcpExample)
 
 
-set(CMAKE_CXX_STANDARD 14)
+
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pthread")
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 

src/example/thread/CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.8)
 project(ThreadExample)
 
 
-set(CMAKE_CXX_STANDARD 14)
+
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pthread")
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 

src/factory/CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.8)
 
 project(Factory VERSION ${CppUtils_VERSION_MAJOR}.${CppUtils_VERSION_MINOR} LANGUAGES CXX)
 
-set(CMAKE_CXX_STANDARD 14)
+
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
 
 include (GNUInstallDirs)

src/factory/test/CMakeLists.txt

@@ -2,12 +2,12 @@ cmake_minimum_required(VERSION 3.4)
 project(FactoryTest)
 
 
-set(CMAKE_CXX_STANDARD 14)
+
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pthread")
 
 
 enable_testing()
-find_package(GTest REQUIRED)
+include(GoogleTest)
 
 if(NOT TARGET CppUtils::Factory)
     find_package(Factory CONFIG REQUIRED)
@@ -25,7 +25,7 @@ message("FILES ${SRCS}")
 
 add_executable(Test_factory ${SRCS})
 target_include_directories(Test_factory PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/inc)
-target_link_libraries(Test_factory ${GTEST_BOTH_LIBRARIES})
+target_link_libraries(Test_factory  GTest::gtest_main)
 
 add_test(FactoryTests Test_factory --gtest_output=xml)
 

src/graphs/test/CMakeLists.txt

@@ -2,12 +2,12 @@ cmake_minimum_required(VERSION 3.4)
 project(GraphsTest)
 
 
-set(CMAKE_CXX_STANDARD 14)
+
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pthread")
 
 
 enable_testing()
-find_package(GTest REQUIRED)
+include(GoogleTest)
 
 
 
@@ -27,11 +27,11 @@ include_directories(inc)
 include_directories(${graphs_INCLUDE_DIRS})
 
 file(GLOB SRCS ${CMAKE_CURRENT_SOURCE_DIR}/test/src/*.cpp)
-message("LIBS ${GTEST_BOTH_LIBRARIES}")
+message("LIBS  GTest::gtest_main")
 
 add_executable(Test_graphs ${SRCS})
 target_include_directories(Test_graphs PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/inc)
-target_link_libraries(Test_graphs ${GTEST_BOTH_LIBRARIES})
+target_link_libraries(Test_graphs  GTest::gtest_main)
 
 add_test(GraphsTests Test_graphs --gtest_output=xml)
 

src/linux/CMakeLists.txt

@@ -0,0 +1,3 @@
+# set(CMAKE_CXX_COMPILER "/usr/bin/x86_64-linux-gnu-g++-12")
+add_subdirectory(futex)
+add_subdirectory(shm)

src/linux/futex/CMakeLists.txt

@@ -0,0 +1,49 @@
+cmake_minimum_required(VERSION 3.8)
+
+project(Futex VERSION ${CppUtils_VERSION_MAJOR}.${CppUtils_VERSION_MINOR} LANGUAGES CXX) 
+
+
+include (GNUInstallDirs)
+
+
+include_directories(inc)
+
+file(GLOB SRC_FILES
+    "src/*.cpp"
+)
+
+file(GLOB HEADER_FILES   
+    "inc/*.h"
+)
+
+add_library(Futex INTERFACE )
+target_link_libraries(Futex INTERFACE CppUtils::Shm)
+
+set( futex_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/inc" CACHE STRING "Include-directories for futex" FORCE )
+
+
+add_library(CppUtils::Futex ALIAS Futex)
+
+
+install (TARGETS Futex EXPORT FutexTargets 
+         LIBRARY DESTINATION lib/cpputils/futex
+         INCLUDES DESTINATION include/cpputils/futex)
+
+install (EXPORT FutexTargets 
+         DESTINATION lib/cpputils/cmake/Futex
+         FILE   FutexTargets.cmake
+         NAMESPACE CppUtils::)
+
+install (DIRECTORY inc/futex 
+         DESTINATION include/cpputils)
+
+include (CMakePackageConfigHelpers)
+write_basic_package_version_file(FutexConfigVersion.cmake COMPATIBILITY SameMajorVersion)
+install (FILES FutexConfig.cmake ${CMAKE_CURRENT_BINARY_DIR}/FutexConfigVersion.cmake
+         DESTINATION lib/cmake/cpputils/Futex)
+
+
+if( ENABLE_TEST )
+    message("Unit test enabled")
+    include(${CMAKE_CURRENT_SOURCE_DIR}/test/CMakeLists.txt)
+endif()

src/linux/futex/FutexConfig.cmake

@@ -0,0 +1,7 @@
+include (CMakeFindDependencyMacro)
+
+# set(SOCKETS_LIBRARIES Sockets)
+# FIND_LIBRARY(SOCKETS_LIBRARIES NAMES "Sockets" HINTS "/usr/local/lib/cpputils/sockets/")
+
+
+include ("${CMAKE_CURRENT_LIST_DIR}/FutexTargets.cmake")

src/linux/futex/inc/futex/futex.hpp

@@ -0,0 +1,136 @@
+/**
+ * @file futex.hpp
+ * @brief Implementation of a futex-based mutex.
+ *
+ * This file contains the implementation of a mutex using futexes, based on Ulrich Drepper's
+ * "Futexes Are Tricky" paper.
+ *
+ * @see https://www.akkadia.org/drepper/futex.pdf
+ */
+
+#pragma once
+
+#include <atomic>
+#include <cstdint>
+#include <iostream>
+#include <sstream>
+#include <thread>
+
+#include <linux/futex.h>
+#include <pthread.h>
+#include <sys/resource.h>
+#include <sys/shm.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+namespace CppUtils
+{
+
+// 0 means unlocked
+const int UNLOCKED(0);
+// 1 means locked, no waiters
+const int LOCKED_NO_WAITERS(1);
+// 2 means locked, there are waiters in lock()
+const int LOCKED(2);
+
+// An atomic_compare_exchange as expected in the paper
+static int cmpxchg(std::atomic<int>* atom, int expected, int desired)
+{
+    int* ep = &expected;
+    std::atomic_compare_exchange_strong(atom, ep, desired);
+    return *ep;
+}
+
+/// @brief Futex-based mutex
+///
+/// This class implements a mutex using futexes. It's based on Ulrich Drepper's "Futexes Are
+/// Tricky" paper.
+///
+/// @see https://www.akkadia.org/drepper/futex.pdf
+class Futex
+{
+public:
+    /// @brief Default constructor
+    Futex()
+        : free_resources(true)
+    {
+        ptr_atom = new std::atomic<int>;
+        ptr_atom->store(UNLOCKED);
+    }
+
+    /// @brief Constructor that allows to pass a pointer to the atomic to use
+    /// @param val_atomic Pointer to atomic value
+    Futex(std::atomic<int>* val_atomic)
+        : ptr_atom(val_atomic)
+        , free_resources(false)
+    {
+        ptr_atom->store(UNLOCKED);
+    }
+
+    /// @brief Locks the mutex
+    void lock()
+    {
+        int c = cmpxchg(ptr_atom, UNLOCKED, LOCKED_NO_WAITERS);
+        // If the lock was previously unlocked, there's nothing else for us to do.
+        // Otherwise, we'll probably have to wait.
+        if (c != UNLOCKED) {
+            do {
+                // If the mutex is locked, we signal that we're waiting by setting the
+                // atom to 2. A shortcut checks is it's 2 already and avoids the atomic
+                // operation in this case.
+                if (c == LOCKED || cmpxchg(ptr_atom, LOCKED_NO_WAITERS, LOCKED) != UNLOCKED) {
+                    // Here we have to actually sleep, because the mutex is actually
+                    // locked. Note that it's not necessary to loop around this syscall;
+                    // a spurious wakeup will do no harm since we only exit the do...while
+                    // loop when ptr_atom is indeed 0.
+                    syscall(SYS_futex, reinterpret_cast<int*>(ptr_atom), FUTEX_WAIT, LOCKED, 0, 0, 0);
+                }
+                // We're here when either:
+                // (a) the mutex was in fact unlocked (by an intervening thread).
+                // (b) we slept waiting for the atom and were awoken.
+                //
+                // So we try to lock the atom again. We set teh state to 2 because we
+                // can't be certain there's no other thread at this exact point. So we
+                // prefer to err on the safe side.
+            } while ((c = cmpxchg(ptr_atom, UNLOCKED, LOCKED)) != UNLOCKED);
+        }
+    }
+
+    /// @brief Unlock the mutex
+    void unlock()
+    {
+        if (ptr_atom->fetch_sub(1) != LOCKED_NO_WAITERS) {
+            ptr_atom->store(UNLOCKED);
+            syscall(SYS_futex, reinterpret_cast<int*>(ptr_atom), FUTEX_WAKE, LOCKED_NO_WAITERS, 0, 0, 0);
+        }
+    }
+
+    /// @brief Notifies the number of waiters
+    /// @param number_of_waiters
+    /// @return -1 on ERROR, 0 on success
+    int32_t post(uint32_t number_of_waiters)
+    {
+        return syscall(SYS_futex, reinterpret_cast<int*>(ptr_atom), FUTEX_WAKE, number_of_waiters, 0, 0, 0);
+    }
+
+    /// @brief Wait for the value to change
+    /// @param wait_value Value to wait for
+    /// @return -1 on ERROR, 0 on success
+    int32_t wait(uint32_t wait_value)
+    {
+        return syscall(SYS_futex, reinterpret_cast<int*>(ptr_atom), FUTEX_WAIT, wait_value, 0, 0, 0);
+    }
+
+    /// @brief Destructor
+    virtual ~Futex()
+    {
+        if (free_resources) {
+            delete ptr_atom;
+        }
+    }
+
+private:
+    std::atomic<int>* ptr_atom;
+    bool free_resources;
+};
+}  // namespace CppUtils