Fix for bug #18401, makes shuffle() properly generate all possibilities.

Patch provided by Adam Trachtenberg <adam@trachtenberg.com>

diff --git a/ext/standard/array.c b/ext/standard/array.c
index 0c8ad6c11189cb1f675e7e9ee029175782546f75..de666674f3e852c27b67d0b68d0be10c33bf745a 100644 (file)
--- a/ext/standard/array.c
+++ b/ext/standard/array.c
@@ -1441,7 +1441,7 @@ static void array_data_shuffle(zval *array TSRMLS_DC)
 {
        Bucket **elems, *temp;
        HashTable *hash;
-       int j, n_elems, cur_elem = 0, rnd_idx, n_left;
+       int j, n_elems, rnd_idx, n_left;
 
        n_elems = zend_hash_num_elements(Z_ARRVAL_P(array));
        
@@ -1457,13 +1457,12 @@ static void array_data_shuffle(zval *array TSRMLS_DC)
                elems[j++] = temp;
        while (--n_left) {
                rnd_idx = php_rand(TSRMLS_C);
-               RAND_RANGE(rnd_idx, cur_elem, n_left, PHP_RAND_MAX);
-               if (rnd_idx != cur_elem) {
-                       temp = elems[cur_elem];
-                       elems[cur_elem] = elems[rnd_idx];
+               RAND_RANGE(rnd_idx, 0, n_left, PHP_RAND_MAX);
+               if (rnd_idx != n_left) {
+                       temp = elems[n_left];
+                       elems[n_left] = elems[rnd_idx];
                        elems[rnd_idx] = temp;
                }
-               cur_elem++;
        }
 
        HANDLE_BLOCK_INTERRUPTIONS();