Hi On 2/17/22 08:37, Go Kudo wrote:
The following points have been fixed:- `nextByteSize(): int` has been removed from Random\Engine - If the width of the RNG is statically defined, it will now be used preferentially - Added Xoshiro256StarStar - Fixed an endianness issue And updated RFC https://wiki.php.net/rfc/rng_extension [...] This seems to have solved the whole problem. How about it?
Awesome, this is feeling much much better now. As you might've seen I've made some comments on GitHub regarding implementation bugs.
I have two more conceptional questions: ----------- 1)However I believe you did not answer my question regarding the following and that's something that should be clear in the RFC and documentation:
<?php
use Random\Engine\Xoshiro256StarStar;
use Random\Randomizer;
$g1 = new Xoshiro256StarStar(1);
$g2 = clone $g1;
$r1 = new Randomizer($g1);
$r2 = new Randomizer($g2);
var_dump(\bin2hex($r1->getBytes(8))); // string(16) "c510c70f6daff2b3"
var_dump(\bin2hex($r2->getBytes(4) . $r2->getBytes(4))); //
string(16) "c510c70fea4c3647"
In this example I get 8 bytes from the randomizer. One time by getting all 8 bytes at once, the second time by getting 4 bytes and then another 4 bytes.
I think that both lines should result in the same output, because in both cases I am getting 8 bytes, without any other operations that might affect the engine state in between. As a user I should not be required to know how the Randomizer works internally (by always getting 8 bytes from the engine and throwing away unused bytes).
If you disagree and think this is the correct behavior then this should be documented accordingly in the RFC. If you agree, then this should be fixed and a testcase be added.
----------- 2)This ties into (1): Currently any additional bytes returned by the engine are silently ignored. Either the bytes should be processed in full, or an error emitted if the returned bytestring is too long.
Consider the attached test case with a Sha1-based RNG. If I grab 20 bytes (the length of a SHA-1 hash) from the Randomizer then the 'generate()' function will be called 3 times, despite it returning sufficient bytes on the first attempt. If I want to make sure that no bytes are wasted, then I need to implement a pretty complex construction (Sha1_2) to always return exactly 8 bytes.
Best regards Tim Düsterhus
<<attachment: test_rng.php>>
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