random: Add clarifying comments to the implementation of CombinedLCG

The implementation is needlessly obfuscated. It's not immediately clear that
MODMULT is a simple modular multiplicati

random: Add clarifying comments to the implementation of CombinedLCG

The implementation is needlessly obfuscated. It's not immediately clear that
MODMULT is a simple modular multiplication, despite its name. Specifically it's
not clear which of the parameters is the second factor.

Furthermore the stated period is off-by-one: A value of `0` is part of its own
chain, thus it may not be included in the period of the underlying generators.

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random: Use CSPRNG for CombinedLCG seeding (#13748)

Now that the CombinedLCG is no longer used within GENERATE_SEED(), we can
safely use the CSPRNG with a php_random_generate_fallback_se

random: Use CSPRNG for CombinedLCG seeding (#13748)

Now that the CombinedLCG is no longer used within GENERATE_SEED(), we can
safely use the CSPRNG with a php_random_generate_fallback_seed() fallback to
seed the CombinedLCG.

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random: Clean up seeding API (#13540)

* random: Expose xoshiro256**'s seeding functions

* random: Expose pcgoneseq128xslrr64's seeding functions

* random: Expose Mt19937's

random: Clean up seeding API (#13540)

* random: Expose xoshiro256**'s seeding functions

* random: Expose pcgoneseq128xslrr64's seeding functions

* random: Expose Mt19937's seeding functions

* random: Expose CombinedLCG's seeding functions

* random: Call php_random_mt19937_seed32 to seed the global Mt19937

This avoids the function pointer indirection and improves type safety.

* random: NULL the generic seeding function

Different engines work quite differently, it is not useful to attempt to seed
them in a generic way using a 64 bit integer. As an example Mt19937 completely
ignores the upper 32 bits.

* random: Remove the `seed` member from `php_random_algo`

See the explanation in the previous commit for the reasoning. This member is
unused since the previous commit and was not consistently available even before
that (specifically for the Secure engine).

* UPGRADING.INTERNALS

* random: Remove useless cast in `php_mt_srand()`

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random: Adjust `status` to `state` (#13521)

* random: Rename `status` local to `state`

* random: Rename `php_random_algo_with_state`'s `status` member to `state`

random: Pass algorithm and state together as `php_random_algo_with_state` (#13350)

* random: Remove `php_random_status`

Since 162e1dce9870168cb8c65c013f2b5a510b6536b1, the `php_rand

random: Pass algorithm and state together as `php_random_algo_with_state` (#13350)

* random: Remove `php_random_status`

Since 162e1dce9870168cb8c65c013f2b5a510b6536b1, the `php_random_status` struct
contains just a single `void*`, resulting in needless indirection when
accessing the engine state and thus decreasing readability because of the
additional non-meaningful `->state` references / the local helper variables.

There is also a small, but measurable performance benefit:

<?php
$e = new Random\Engine\Xoshiro256StarStar(0);
$r = new Random\Randomizer($e);

for ($i = 0; $i < 15; $i++)
var_dump(strlen($r->getBytes(100000000)));

goes from roughly 3.85s down to 3.60s.

The names of the `status` variables have not yet been touched to keep the diff
small. They will be renamed to the more appropriate `state` in a follow-up
cleanup commit.

* Introduce `php_random_algo_with_state`

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random: Optimize data flow for the `generate` function of native engines (#13043)

Instead of returning the generated `uint64_t` and providing the size (i.e. the
number of bytes of the ge

random: Optimize data flow for the `generate` function of native engines (#13043)

Instead of returning the generated `uint64_t` and providing the size (i.e. the
number of bytes of the generated value) out-of-band via the
`last_generated_size` member of the `php_random_status` struct, the `generate`
function is now expected to return a new `php_random_result` struct containing
both the `size` and the `result`.

This has two benefits, one for the developer:

It's no longer possible to forget setting `last_generated_size` to the correct
value, because it now happens at the time of returning from the function.

and the other benefit is for performance:

The `php_random_result` struct will be returned as a register pair, thus the
`size` will be directly available without reloading it from main memory.

Checking a simplified version of `php_random_range64()` on Compiler Explorer
(“Godbolt”) with clang 17 shows a single change in the resulting assembly
showcasing the improvement (https://godbolt.org/z/G4WjdYxqx):

- add rbp, qword ptr [r14]
+ add rbp, rdx

Empirical testing confirms a measurable performance increase for the
`Randomizer::getBytes()` method:

<?php
$e = new Random\Engine\Xoshiro256StarStar(0);
$r = new Random\Randomizer($e);

var_dump(strlen($r->getBytes(100000000)));

goes from 250ms (before the change) to 220ms (after the change). While
generating 100 MB of random data certainly is not the most common use case, it
confirms the theoretical improvement in practice.

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Add ext/random Exception hierarchy (#9220)

* Add Random\Random{Error,Exception} and Random\BrokenRandomEngineError

* Throw BrokenRandomEngineError

* Throw RandomException o

Add ext/random Exception hierarchy (#9220)

* Add Random\Random{Error,Exception} and Random\BrokenRandomEngineError

* Throw BrokenRandomEngineError

* Throw RandomException on seeding failure

* Throw RandomException when CSPRNG fails

* Remove unused include from ext/random/engine_combinedlcg.c

* Remove unused include from ext/random/engine_secure.c

* Remove unused include from ext/random/random.c

* [ci skip] Add ext/random Exception hierarchy to NEWS

* [ci skip] Add the change of Exception for random_(int|bytes) to UPGRADING

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[ci skip] Update EXTENSIONS and Author(s) in ext/random (#9074)

php.net account is better suited for this cases.

Implement Random Extension

https://wiki.php.net/rfc/rng_extension
https://wiki.php.net/rfc/random_extension_improvement