From e2b1f449971db46a752e6c963d4735660433be45 Mon Sep 17 00:00:00 2001
From: Jan Grewe <jan.grewe@g-node.org>
Date: Thu, 12 Mar 2020 17:47:53 +0100
Subject: [PATCH] [buffer] working circular buffer

---
 imagebuffer.cpp | 68 +++++++++++++++++++++++++++++++++++++++++++++++--
 imagebuffer.h   | 26 ++++++++++++++++++-
 2 files changed, 91 insertions(+), 3 deletions(-)

diff --git a/imagebuffer.cpp b/imagebuffer.cpp
index 9c792b5..6e2632f 100644
--- a/imagebuffer.cpp
+++ b/imagebuffer.cpp
@@ -1,6 +1,70 @@
 #include "imagebuffer.h"
 
-ImageBuffer::ImageBuffer(QObject *parent) : QObject(parent)
-{
+ImageBuffer::ImageBuffer(size_t buffer_size, QObject *parent) : QObject(parent), buffer_size(buffer_size) {
+  buffer.resize(buffer_size);
+}
+
+void ImageBuffer::clear() {
+  resize(buffer_size);
+}
+
+size_t ImageBuffer::capacity() {
+  return buffer.capacity();
+}
+
+double ImageBuffer::bufferPreassure() {
+  double preassure;
+  mutex.lock();
+  preassure = static_cast<double>(load)/static_cast<double>(buffer.capacity());
+  mutex.unlock();
+  return preassure * 100;
+}
+
+int64_t ImageBuffer::bufferLoad() {
+  int64_t l;
+  mutex.lock();
+  l = load;
+  mutex.unlock();
+  return l;
+}
+
+void ImageBuffer::resize(size_t new_size) {
+  mutex.lock();
+  buffer_size = new_size;
+  buffer.clear();
+  buffer.resize(new_size);
+  current_read_index = -1;
+  current_write_index = -1;
+  load = 0;
+  mutex.unlock();
+}
+
+void ImageBuffer::push(const MyImage &img) {
+  mutex.lock();
+  static_cast<size_t>(current_write_index) < (buffer.size() - 1) ? current_write_index += 1 : current_write_index = 0;
+  buffer[static_cast<size_t>(current_write_index)] = img;
+  if (load < static_cast<int64_t>(buffer.capacity()))
+    load += 1;
+  mutex.unlock();
+}
+
+bool ImageBuffer::bufferNotEmpty() {
+  bool res;
+  mutex.lock();
+  res = load > 0;
+  mutex.unlock();
+  return res;
+}
 
+bool ImageBuffer::pop(MyImage &img) {
+  bool ret = false;
+  mutex.lock();
+  if (load > 0) {
+    img = buffer[static_cast<size_t>(current_read_index)];
+    static_cast<size_t>(current_read_index) < (buffer.capacity() - 1) ? current_read_index += 1 : current_read_index = 0;
+    load -= 1;
+  }
+  mutex.unlock();
+  return ret;
 }
+
diff --git a/imagebuffer.h b/imagebuffer.h
index bfc6056..1d5e708 100644
--- a/imagebuffer.h
+++ b/imagebuffer.h
@@ -1,14 +1,38 @@
 #ifndef IMAGEBUFFER_H
 #define IMAGEBUFFER_H
 
+#include <QMutex>
 #include <QObject>
+#include <QWaitCondition>
+#include <myimage.h>
 
 
 class ImageBuffer : public QObject
 {
   Q_OBJECT
 public:
-  explicit ImageBuffer(QObject *parent = nullptr);
+  explicit ImageBuffer(size_t buffer_size=100, QObject *parent = nullptr);
+
+  void clear();
+  void resize(size_t new_size);
+  void push(const MyImage &img);
+  bool pop(MyImage &img);
+  size_t capacity();
+  double bufferPreassure();
+  int64_t bufferLoad();
+  bool bufferNotEmpty();
+
+private:
+  // QWaitCondition bufferNotEmpty; // signals that the consumer can get data
+  // QWaitCondition bufferNotFull; // signals that the producer can store data
+  QMutex mutex;
+  int numUsedBytes = 0;
+
+  std::vector<MyImage> buffer;
+  int64_t current_write_index = -1;
+  int64_t current_read_index = 0;
+  int64_t load = 0;
+  size_t buffer_size;
 
 signals: