From 79914fb9b91b373a81ff0f964dd0b92643a1fbf3 Mon Sep 17 00:00:00 2001
From: walterzhaojr <519362600@qq.com>
Date: Thu, 4 Jun 2020 14:45:47 +0000
Subject: [PATCH] add producer_consumer design_pattern

---
 .../producer_consumer/producer_consumer.cpp   | 104 ++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 design_pattern/producer_consumer/producer_consumer.cpp

diff --git a/design_pattern/producer_consumer/producer_consumer.cpp b/design_pattern/producer_consumer/producer_consumer.cpp
new file mode 100644
index 0000000..534cff8
--- /dev/null
+++ b/design_pattern/producer_consumer/producer_consumer.cpp
@@ -0,0 +1,104 @@
+#include <iostream>
+#include <vector>
+#include <mutex>
+#include <thread>
+#include <condition_variable>
+#include <unistd.h>
+
+using namespace std;
+
+const int MAX_NUM = 10000;
+
+class BoundedBuffer
+{
+public:
+  BoundedBuffer(size_t n) {
+    array_.resize(n);
+    start_pos_ = 0;
+    end_pos_ = 0;
+    pos_ = 0;
+  }
+  void Produce(int n) {
+    {
+      std::unique_lock<std::mutex> lock(mtx_);
+      //wait for not full
+      not_full_.wait(lock, [=] { return pos_ < array_.size(); });
+
+      usleep(1000 * 400);
+      array_[end_pos_] = n;
+      end_pos_ = (end_pos_ + 1) % array_.size();
+      ++pos_;
+      cout << "Produce pos:" << pos_ << endl;
+    } //auto unlock
+
+    not_empty_.notify_one();
+  }
+  
+  int Consume() {
+    std::unique_lock<std::mutex> lock(mtx_);
+    //wait for not empty
+    not_empty_.wait(lock, [=] { return pos_ > 0; });
+    
+    usleep(1000 * 400);
+    int n = array_[start_pos_];
+    start_pos_ = (start_pos_ + 1) % array_.size();
+    --pos_;
+    cout << "Consume pos:" << pos_ << endl;
+    lock.unlock();
+
+    not_full_.notify_one();
+
+    return n;
+  }
+private:
+  std::vector<int> array_;
+  size_t start_pos_;
+  size_t end_pos_;
+  size_t pos_;
+  std::mutex mtx_;
+  std::condition_variable not_full_;
+  std::condition_variable not_empty_;
+};
+
+BoundedBuffer bb(10);
+std::mutex g_mtx;
+
+void Producer()
+{
+  int n = 0;
+  while(n < 100) {
+    bb.Produce(n);
+    cout << "Producer:" << n << endl;
+    n++;
+  }
+
+  bb.Produce(-1);
+}
+
+
+void Consumer()
+{
+  std::thread::id thread_id = std::this_thread::get_id();
+  int n = 0;
+  do {
+    n = bb.Consume();
+    cout << "Consumer thread:" << thread_id << "=====> " << n << endl;
+  } while(-1 != n);
+
+  bb.Produce(-1);
+}
+
+int main()
+{
+  std::vector<std::thread> t;
+  t.push_back(std::thread(&Producer));
+  t.push_back(std::thread(&Consumer));
+  t.push_back(std::thread(&Consumer));
+  t.push_back(std::thread(&Consumer));
+  
+  for (auto& one : t) {
+    one.join();
+  }
+
+  return 0;
+}