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Date: Sat, 2 Jan 2021 04:22:37 +0900
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To: Marc <marc@mabe.berlin>, internals@lists.php.net
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Subject: Re: [PHP-DEV] Re: Improving PRNG implementation.
From: zeriyoshi@gmail.com (Go Kudo)

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Hi Marc, and sorry for the late reply. Email has been marked as spam...

> I would expect the Random number generator to implement from Iterator
using an integer for current() value
> and providing utility functions (simple functions or methods of another
class) for shuffle, random array entry like this:

Thank you very much. This suggestion makes sense and looks very structured.

However, I feel that in the PHP world, this structuring is a bit too much.
Ease of use is very important in PHP.

Nevertheless, I am satisfied with this proposal. I'd like to hear from
someone who is more familiar with the PHP context about the form of the
implementation.

But, it may be faster to actually hold a vote to ask this question. I'm not
sure how much support this proposal has at this point, but do you think
it's worth a try?


2020=E5=B9=B412=E6=9C=8829=E6=97=A5(=E7=81=AB) 18:26 Marc <marc@mabe.berlin=
>:

> Hi zeriyoshi,
> On 23.12.20 14:41, zeriyoshi wrote:
>
> Thanks tyson.
>
>
> This would also make it easier to use those generators in brand new
>
> algorithms that weren't in the initial RFC.
>
> (or in algorithms written by users in PHP)
>
> This suggestion seems to make sense. Maybe the RNG should only focus on
> generating random numbers and not anything else.
> However, the fact that array and string manipulation functions are no
> longer native to C may have a speed disadvantage.
>
> So I came up with the idea of minimizing the interface definition as RNG.
>
> ```
> interface PRNGInterface
> {
>     public function nextInt(?int $min =3D null, ?int $max =3D null): int;
>     public function nextDouble(): double; // maybe, non-needed.
>     public function nextByte(int $length): string;
> }
> ```
>
> The methods for array and string operations are defined separately as
> interfaces that inherit from the interface.
>
> ```
> interface RandomInterface extends PRNGInterface
> {
>     public function shuffle(array &$array): bool;
>     public function arrayRand(array $array, int $num =3D 1): int|string|a=
rray;
>     public function strShuffle(string $string): string;
> }
> ```
>
> This can be overly structured, but it will serve all purposes.
>
> Personally I feel the interfaces still looking a bit off to me.
>
> I would expect the Random number generator to implement from Iterator
> using an integer for `current()` value
>
> and providing utility functions (simple functions or methods of another
> class) for shuffle, random array entry like this:
>
> ```php
>
> interface RNG extends Iterator {
>     public function rewind();
>     public function next();
>     public function current(): int;
>     public function key(): int;
>     public function valid();
> }
>
>
> interface PRNG extends RNG {
>     public function __current(int $seed);
>     public function getSeed(): int;
> }
>
> class RNGUtil {
>     public static function shuffleArray(int $randomNumber, array $arr): a=
rray;
>     public static function randomArrayElement(int $randomNumber, array $a=
rr): mixed;
>     public static function between(int $randomNumber, int $min =3D PHP_IN=
T_MIN, int $max =3D PHP_INT_MAX): int;
>     public static function bytes(RNG $rng, int $length): string;
> }
>
> ```
>
>
> Regards,
> Go Kudo
>
>
> 2020=E5=B9=B412=E6=9C=8823=E6=97=A5(=E6=B0=B4) 0:40 tyson andre <tysonand=
re775@hotmail.com> <tysonandre775@hotmail.com>:
>
>
> Hi Go Kudo,
>
> **A possible alternative that is widely used in other programming
> languages is to limit the interface API to only generating bytes/integers=
,**
> and to provide global functions that would use generic random number
> generator objects (from internal or user-provided code) in their algorith=
ms.
>
> This would also make it easier to use those generators in brand new
> algorithms that weren't in the initial RFC.
> (or in algorithms written by users in PHP)
>
> This alternative is similar to Javahttps://docs.oracle.com/javase/7/docs/=
api/java/util/Collections.html#shuffle(java.util.List,%20java.util.Random)
> and https://docs.oracle.com/javase/7/docs/api/java/util/Random.html
> and C++ https://www.cplusplus.com/reference/algorithm/shuffle/
> where the algorithms accept a random number generator conforming to some
> interface
> and Python https://docs.python.org/3/library/random.html#random.shuffle
>
> ```
> interface PRNGInterface {
>     public function random[Signed]Int(): int;  // between PHP_INT_MIN and
> PHP_INT_MAX (4 bytes or 8 bytes)
>     public function randomBytes(int $length): string // $length bytes of
> raw data
>     // possibly randomByte(): int // between 0 and 255
>     // public function randomIntInRange(int $min, int $max)
>     // __serialize(), __unserialize() may be provided, but may be
> counterproductive for classes that wrap /dev/urandom or random_bytes()?
> }
> // possibly provide a trait that provides defaults based on abstract
> function randomInt
>
> function whateverprefixornamespace_rand(PRNGInterface $rng, [int $min, in=
t
> $max]): int {}
> // If this is intended to be secure, whateverprefix_array_rand may need t=
o
> avoid the optimizations used by array_rand for sparse arrays
> function whateverprefixornamespace_array_rand(PRNGInterface $rng, array
> $array, ...): int {}
> function whateverprefixornamespace_shuffle(PRNGInterface $rng, array
> &$array): bool;
> // alternately might be possible by extending existing global functions
> with an optional parameter
> ```
>
> Thanks,
> - Tyson
>
>

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