Initialized the libc random generator using the time and the process ID.

1 files changed, 14 insertions, 3 deletions

diff --git a/src/common/shuffle.c b/src/common/shuffle.c
index 6b20866..e2e0a3d 100644
--- a/src/common/shuffle.c
+++ b/src/common/shuffle.c
@@ -53,6 +53,14 @@ void shuffle(void *base, size_t nmemb, size_t size)
      * Application de l'algorithme Fisher-Yates.
      *
      * Cf. https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle
+     *
+     * En version hors-ligne, cela donne :
+     *
+     *    -- To shuffle an array a of n elements (indices 0..n-1):
+     *    for i from 0 to n−2 do
+     *        j ← random integer such that i ≤ j < n
+     *        exchange a[i] and a[j]
+     *
      */
 
     if (nmemb > 1)
@@ -65,9 +73,12 @@ void shuffle(void *base, size_t nmemb, size_t size)
         {
             j = i + rand() % (nmemb - i);
 
-            memcpy(tmp, list + i * size, size);
-            memcpy(list + i * size, list + j * size, size);
-            memcpy(list + j * size, tmp, size);
+            if (j != i)
+            {
+                memcpy(tmp, list + i * size, size);
+                memcpy(list + i * size, list + j * size, size);
+                memcpy(list + j * size, tmp, size);
+            }
 
         }