From 004ee52ae422d27b1ba03d795d23a2fe0c096365 Mon Sep 17 00:00:00 2001
From: Ivaylo Ivanov <me@ivayloivanov.eu>
Date: Sun, 13 Jan 2019 14:18:20 +0100
Subject: [PATCH] Add shuffler and paramaterize the open_sem function
 additionally

---
 fb_arc_set/generator.c  | 67 ++++++++++++++++++++++++++++++++++++++++-
 fb_arc_set/shared/sem.c | 15 +++++++--
 fb_arc_set/supervisor.c |  5 +--
 3 files changed, 81 insertions(+), 6 deletions(-)

diff --git a/fb_arc_set/generator.c b/fb_arc_set/generator.c
index 4256a3d..8009e5b 100644
--- a/fb_arc_set/generator.c
+++ b/fb_arc_set/generator.c
@@ -30,6 +30,10 @@
 #include "shared/sem.c"
 #include "shared/structs.c"
 #include <regex.h>
+#include <time.h>
+
+void swap(int *a, int *b);
+void shuffle(int arr[], size_t size);
 
 int main(int argc, char *argv[]) {
     if(argc < 2) {
@@ -76,13 +80,74 @@ int main(int argc, char *argv[]) {
     }
     num_nodes++; ///< Our first node is labeled 0, so we need to add 1 more
 
-    printf("%d", num_nodes);
+    /// Declare arrays for unique nodes and for the chosen edges
+    int unique_nodes[num_nodes];
+    bool chosen_edges[num_edges];
+
+    /// Filling the node array with the nodes
+    for(int i=0; i < num_nodes; i++) {
+        unique_nodes[i] = i;
+    }
+
+    /// Marking all edges as not chosen
+    for(int i=0; i < num_edges; i++) {
+        chosen_edges[i] = false;
+    }
 
     /// Allocate resources for circular buffer
+    int wr_pos = 0;
     buffer_shmfd = create_shmfd(BUFF_SHM_NAME);
     circ_buffer = (buffer_t *)open_shm(buffer_shmfd, sizeof(buffer_t));
 
+    /// Open semaphores
+    free_sem = open_sem(FREE_SEM_NAME, BUFF_SIZE, 1);
+    use_sem = open_sem(USE_SEM_NAME, 0, 1);
+    mutex = open_sem(MUTEX_NAME, 1, 1);
 
+    int best_solution = num_edges - 1; ///< Set a basic best solution
+
+    /// Declaring buffer arrays
+    int buf_nodes[num_nodes];
+    int buf_chosen_edges[num_edges];
+
+    while(terminate != true && circ_buffer->finished != true) { ///< Loop until told to stop or until an acyclic solution is discovered
+        /// Copy the original into a buffer array and shuffle it
+        memcpy(buf_nodes, unique_nodes, sizeof(unique_nodes));
+        shuffle(buf_nodes, num_nodes);
+
+        /// Reset the chosen status of the array
+        memcpy(buf_chosen_edges, chosen_edges, sizeof(chosen_edges));
+    }
 
     exit(EXIT_SUCCESS);
 }
+
+/**
+ * @brief Function that swaps a two variables
+ * @details The function takes pointers to two variables and swaps their values with a buffer variable
+ * @param *a, *b
+ * @return none
+ **/
+void swap(int *a, int *b) {
+    int temp = *a;
+    *a = *b;
+    *b = temp;
+}
+
+/**
+ * @brief Function that shuffles a given array
+ * @details The function takes an array and shuffles it randomly using the Fisher-Yates algorithm:
+ *          https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle
+ * @param arr, size
+ * @return res
+ **/
+void shuffle(int arr[], size_t size) {
+
+    srand(time(NULL)); ///< Set a random seed
+
+    int j = 0; ///< Index that will be randomized later on
+    for(int i = size - 1; i > 0; i--) {
+        j = rand()%(i+1); ///< Pick a random index
+        swap(&arr[i], &arr[j]); ///< Swap the values
+    }
+}
diff --git a/fb_arc_set/shared/sem.c b/fb_arc_set/shared/sem.c
index 9ed79cc..f91bfae 100644
--- a/fb_arc_set/shared/sem.c
+++ b/fb_arc_set/shared/sem.c
@@ -22,12 +22,21 @@ static sem_t *mutex;
  * @brief Function that executes sem_open(3) and does error handling.
  * @details The function executes sem_open(3), giving it a semaphor name and size as parameters,
  *          and handles the errors if any. The same behaviour as sem_open(3) should be expected.
+ *          The type parameter is used to determine how the semaphore should be opened:
+ *          - as a supervisor: 0
+ *          - as a generator: 1
  *          Returns a new semaphore
- * @param sem_name, sem_size
+ * @param sem_name, sem_size, type
  * @return res
  **/
-sem_t * open_sem(char *sem_name, size_t sem_size) {
-    sem_t *res = sem_open(sem_name, O_CREAT | O_EXCL, 0600, sem_size);
+sem_t * open_sem(char *sem_name, size_t sem_size, short type) {
+    sem_t *res;
+
+    if(type == 0)
+        res = sem_open(sem_name, O_CREAT | O_EXCL, 0600, sem_size);
+    else
+        res = sem_open(sem_name, sem_size);
+
     if(res == SEM_FAILED) {
         fprintf(stderr, "ERROR: Failed opening semaphore\n");
         exit(EXIT_FAILURE);
diff --git a/fb_arc_set/supervisor.c b/fb_arc_set/supervisor.c
index 0c0142b..7fc65a7 100644
--- a/fb_arc_set/supervisor.c
+++ b/fb_arc_set/supervisor.c
@@ -46,8 +46,9 @@ int main(int argc, char *argv[]) {
     circ_buffer = (buffer_t *)open_shm(buffer_shmfd, sizeof(buffer_t));
 
     /// Open semaphores
-    free_sem = open_sem(FREE_SEM_NAME, BUFF_SIZE);
-    use_sem = open_sem(USE_SEM_NAME, 0);
+    free_sem = open_sem(FREE_SEM_NAME, BUFF_SIZE, 0);
+    use_sem = open_sem(USE_SEM_NAME, 0, 0);
+    mutex = open_sem(MUTEX_NAME, 1, 0);
 
     int free_space = 0;
     int use_space = 0;