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Fix bug #7045: shuffle() now provides consistent distribution of values

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in the array.
This commit is contained in:
Andrei Zmievski 2002-06-10 02:28:32 +00:00
parent 0258d9e2ee
commit 7f4c12b006
2 changed files with 53 additions and 8 deletions
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1
NEWS
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@ -1,6 +1,7 @@
PHP 4 NEWS
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
?? ??? 2002, Version 4.3.0
- Fixed shuffle() to provide equal distribution of values. (Andrei)
- Added --with-mysql-sock configure option which can be used to override
the unix socket location. (e.g. NFS compiles, etc.) (imajes)
- Fixed is_a() to properly work on extension registered classes. (Andrei)

60
ext/standard/array.c
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@ -1435,24 +1435,68 @@ PHP_FUNCTION(range)
/* }}} */
static int array_data_shuffle(const void *a, const void *b TSRMLS_DC)
{
return (php_rand(TSRMLS_C) % 2) ? 1 : -1;
}
/* {{{ proto bool shuffle(array array_arg)
Randomly shuffle the contents of an array */
PHP_FUNCTION(shuffle)
{
zval *array;
Bucket **elems, *temp;
HashTable *hash;
int j, n_elems, cur_elem = 0, rnd_idx, n_left;
TSRMLS_FETCH();
if (zend_parse_parameters(1 TSRMLS_CC, "a", &array) == FAILURE) {
RETURN_FALSE;
}
if (zend_hash_sort(Z_ARRVAL_PP(&array), (sort_func_t)php_mergesort, array_data_shuffle, 1 TSRMLS_CC) == FAILURE) {
RETURN_FALSE;
n_elems = zend_hash_num_elements(Z_ARRVAL_P(array));
if (n_elems <= 1) {
RETURN_TRUE;
}
elems = (Bucket **)emalloc(n_elems * sizeof(Bucket *));
hash = Z_ARRVAL_P(array);
n_left = n_elems;
for (j = 0, temp = hash->pListHead; temp; temp = temp->pListNext)
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];
elems[rnd_idx] = temp;
}
cur_elem++;
}
HANDLE_BLOCK_INTERRUPTIONS();
hash->pListHead = elems[0];
hash->pListTail = NULL;
hash->pInternalPointer = hash->pListHead;
for (j = 0; j < n_elems; j++) {
if (hash->pListTail) {
hash->pListTail->pListNext = elems[j];
}
elems[j]->pListLast = hash->pListTail;
elems[j]->pListNext = NULL;
hash->pListTail = elems[j];
}
temp = hash->pListHead;
j = 0;
while (temp != NULL) {
temp->nKeyLength = 0;
temp->h = j++;
temp = temp->pListNext;
}
hash->nNextFreeElement = n_elems;
zend_hash_rehash(hash);
HANDLE_UNBLOCK_INTERRUPTIONS();
efree(elems);
RETURN_TRUE;
}
/* }}} */