From c0670991b17ae410ad76698720b068e18e95e46c Mon Sep 17 00:00:00 2001
From: Lumijiez <danthevip@gmail.com>
Date: Sun, 8 Dec 2024 19:19:22 +0200
Subject: [PATCH] lab5, reader/writer problem

---
 include/reader_writer.h |  7 +--
 main.cpp                | 26 +++++++++--
 src/reader_writer.cpp   | 97 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 123 insertions(+), 7 deletions(-)

diff --git a/include/reader_writer.h b/include/reader_writer.h
index 7b92969..9e7712e 100644
--- a/include/reader_writer.h
+++ b/include/reader_writer.h
@@ -10,7 +10,7 @@
 
 class ReaderWriter {
 public:
-    ReaderWriter(int numReaders, int numWriters, const std::string& filename);
+    ReaderWriter(int numReaders, int numWriters, std::string  filename);
     ~ReaderWriter();
     void run();
 
@@ -19,9 +19,10 @@ private:
     int numWriters;
     std::string filename;
 
-    sem_t resourceAccess;
-    sem_t readCountAccess;
+    sem_t resourceAccess{};
+    sem_t readCountAccess{};
     int readCount;
+    int writeCount;
 
     static void* reader(void* arg);
     static void* writer(void* arg);
diff --git a/main.cpp b/main.cpp
index 69e5289..aff8b28 100644
--- a/main.cpp
+++ b/main.cpp
@@ -6,6 +6,7 @@
 #include "buffer.h"
 #include "producer.h"
 #include "consumer.h"
+#include "reader_writer.h"
 
 [[noreturn]] void runSignalHandler() {
     setupSignalHandlers();
@@ -45,11 +46,24 @@ void runProducerConsumer() {
     }
 }
 
+void runReaderWriter() {
+    int numReaders = 5;
+    int numWriters = 2;
+    std::string filename = "shared_resource.txt";
+
+    std::ofstream file(filename, std::ios::trunc);
+    file.close();
+
+    ReaderWriter rw(numReaders, numWriters, filename);
+    rw.run();
+}
+
 int main() {
     while (true) {
         std::cout << "=== Main Menu ===\n";
-        std::cout << "1. Run Signal Handler Program\n";
-        std::cout << "2. Run Producer/Consumer Program\n";
+        std::cout << "1. Run Signal Handler\n";
+        std::cout << "2. Run Producer/Consumer\n";
+        std::cout << "3. Run Reader/Writer\n";
         std::cout << "0. Exit\n";
         std::cout << "Enter your choice: ";
 
@@ -58,13 +72,17 @@ int main() {
 
         switch (choice) {
             case 1:
-                std::cout << "Running Signal Handler Program...\n";
+                std::cout << "Running Signal Handler...\n";
             runSignalHandler();
             break;
             case 2:
-                std::cout << "Running Producer/Consumer Program...\n";
+                std::cout << "Running Producer/Consumer...\n";
             runProducerConsumer();
             break;
+            case 3:
+                std::cout << "Running Reader-Writer...\n";
+            runReaderWriter();
+            break;
             case 0:
                 std::cout << "Exiting program. Goodbye!\n";
             return 0;
diff --git a/src/reader_writer.cpp b/src/reader_writer.cpp
index eb2e51f..ecf32fc 100644
--- a/src/reader_writer.cpp
+++ b/src/reader_writer.cpp
@@ -3,3 +3,100 @@
 //
 
 #include "reader_writer.h"
+
+#include <iostream>
+#include <sstream>
+#include <utility>
+#include <unistd.h>
+#include <vector>
+
+ReaderWriter::ReaderWriter(const int numReaders, const int numWriters, std::string filename)
+    : numReaders(numReaders), numWriters(numWriters), filename(std::move(filename)), readCount(0), writeCount(0) {
+    sem_init(&resourceAccess, 0, 1);
+    sem_init(&readCountAccess, 0, 1);
+}
+
+ReaderWriter::~ReaderWriter() {
+    sem_destroy(&resourceAccess);
+    sem_destroy(&readCountAccess);
+}
+
+void* ReaderWriter::reader(void* arg) {
+    auto* rw = static_cast<ReaderWriter*>(arg);
+
+    for (int i = 0; i < 5; ++i) {
+        sem_wait(&rw->readCountAccess);
+        rw->readCount++;
+        if (rw->readCount == 1) {
+            sem_wait(&rw->resourceAccess);
+        }
+        sem_post(&rw->readCountAccess);
+
+        if (std::ifstream file(rw->filename); file.is_open()) {
+            std::ostringstream output;
+            output << "Reader reading: ";
+            std::string line;
+            while (std::getline(file, line)) {
+                output << line << " ";
+            }
+            output << std::endl;
+            std::cout << output.str();
+        } else {
+            std::cerr << "Reader could not open file\n";
+        }
+
+        sem_wait(&rw->readCountAccess);
+        rw->readCount--;
+        if (rw->readCount == 0) {
+            sem_post(&rw->resourceAccess);
+        }
+        sem_post(&rw->readCountAccess);
+
+        sleep(1);
+    }
+    return nullptr;
+}
+
+
+
+void* ReaderWriter::writer(void* arg) {
+    auto* rw = static_cast<ReaderWriter*>(arg);
+
+    for (int i = 0; i < 5; ++i) {
+        sem_wait(&rw->resourceAccess);
+
+        std::ofstream file(rw->filename, std::ios::app);
+        if (file.is_open()) {
+            file << rw->writeCount << "\n";
+            std::cout << "Writer writing: " << rw->writeCount << std::endl;
+            rw->writeCount++;
+        } else {
+            std::cerr << "Writer could not open file\n";
+        }
+        file.close();
+
+        sem_post(&rw->resourceAccess);
+
+        sleep(1);
+    }
+    return nullptr;
+}
+
+void ReaderWriter::run() {
+    std::vector<pthread_t> readerThreads(numReaders);
+    std::vector<pthread_t> writerThreads(numWriters);
+
+    for (int i = 0; i < numReaders; ++i) {
+        pthread_create(&readerThreads[i], nullptr, reader, this);
+    }
+    for (int i = 0; i < numWriters; ++i) {
+        pthread_create(&writerThreads[i], nullptr, writer, this);
+    }
+
+    for (const auto& t : readerThreads) {
+        pthread_join(t, nullptr);
+    }
+    for (const auto& t : writerThreads) {
+        pthread_join(t, nullptr);
+    }
+}
\ No newline at end of file