I think it would be better to either use a correct algorithm or not to
add this function at all. I think it's a reasonable expectation on a
user's part to assume that foo_shuffle() actually does a proper
shuffle. We got all sorts of complaints about the array shuffling code
being broken.
-adam
On Wed, 25 Sep 2002, Andrey Hristov wrote:
> andrey Wed Sep 25 14:06:06 2002 EDT
>
> Modified files:
> /php4/ext/standard basic_functions.c php_string.h string.c
> Log:
> str_shuffle() function added. Like shuffle() for arrays - however the
> algorithm for creating the permutation is quite simple. More like
> the implementation of shuffle() for 4.2.1 .
>
>
> Index: php4/ext/standard/basic_functions.c
> diff -u php4/ext/standard/basic_functions.c:1.511
>php4/ext/standard/basic_functions.c:1.512
> --- php4/ext/standard/basic_functions.c:1.511 Wed Sep 25 11:25:11 2002
> +++ php4/ext/standard/basic_functions.c Wed Sep 25 14:06:05 2002
> @@ -17,7 +17,7 @@
> +----------------------------------------------------------------------+
> */
>
> -/* $Id: basic_functions.c,v 1.511 2002/09/25 15:25:11 wez Exp $ */
> +/* $Id: basic_functions.c,v 1.512 2002/09/25 18:06:05 andrey Exp $ */
>
> #include "php.h"
> #include "php_streams.h"
> @@ -329,6 +329,7 @@
> PHP_FE(strstr,
> NULL)
> PHP_FE(stristr,
> NULL)
> PHP_FE(strrchr,
> NULL)
> + PHP_FE(str_shuffle,
> NULL)
>
> #ifdef HAVE_STRCOLL
> PHP_FE(strcoll,
> NULL)
> Index: php4/ext/standard/php_string.h
> diff -u php4/ext/standard/php_string.h:1.60 php4/ext/standard/php_string.h:1.61
> --- php4/ext/standard/php_string.h:1.60 Tue Aug 20 16:47:47 2002
> +++ php4/ext/standard/php_string.h Wed Sep 25 14:06:05 2002
> @@ -17,7 +17,7 @@
> +----------------------------------------------------------------------+
> */
>
> -/* $Id: php_string.h,v 1.60 2002/08/20 20:47:47 wez Exp $ */
> +/* $Id: php_string.h,v 1.61 2002/09/25 18:06:05 andrey Exp $ */
>
> /* Synced with php 3.0 revision 1.43 1999-06-16 [ssb] */
>
> @@ -82,6 +82,7 @@
> PHP_FUNCTION(substr_count);
> PHP_FUNCTION(str_pad);
> PHP_FUNCTION(sscanf);
> +PHP_FUNCTION(str_shuffle);
> #ifdef HAVE_STRCOLL
> PHP_FUNCTION(strcoll);
> #endif
> Index: php4/ext/standard/string.c
> diff -u php4/ext/standard/string.c:1.297 php4/ext/standard/string.c:1.298
> --- php4/ext/standard/string.c:1.297 Mon Sep 23 10:20:02 2002
> +++ php4/ext/standard/string.c Wed Sep 25 14:06:05 2002
> @@ -18,7 +18,7 @@
> +----------------------------------------------------------------------+
> */
>
> -/* $Id: string.c,v 1.297 2002/09/23 14:20:02 sebastian Exp $ */
> +/* $Id: string.c,v 1.298 2002/09/25 18:06:05 andrey Exp $ */
>
> /* Synced with php 3.0 revision 1.193 1999-06-16 [ssb] */
>
> @@ -3929,6 +3929,39 @@
> zval_copy_ctor(return_value);
>
> php_strtr(Z_STRVAL_P(return_value), Z_STRLEN_P(return_value), rot13_from,
>rot13_to, 52);
> +}
> +/* }}} */
> +
> +
> +static int php_string_shuffle(const void *a, const void *b TSRMLS_DC)
> +{
> + long rnd;
> + rnd = php_rand(TSRMLS_C);
> + if (rnd % 3)
> + return 1;
> + else if (rnd % 5)
> + return 0;
> + else
> + return -1;
> +}
> +
> +/* {{{ proto string str_shuffle(string str)
> + Shuffles string. One permutation of all possible is created */
> +PHP_FUNCTION(str_shuffle)
> +{
> + /* Note : by using current php_string_shuffle for string */
> + /* with 6 chars (6! permutations) about 2/3 of them are */
> + /* computed for 6! calls for the function. So it isn't so */
> + /* unique. The ratio is the same for other lengths. */
> + char *str;
> + int i, str_len;
> +
> + i = 0;
> + if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len) ==
>FAILURE) {
> + RETURN_FALSE;
> + }
> + zend_qsort((void *)str, str_len, sizeof(char), php_string_shuffle TSRMLS_CC);
> + RETURN_STRINGL(str, str_len, 1);
> }
> /* }}} */
>
>
>
>
>
--
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