On a heavily loaded Linux 6.17.5, I observed a maximum of 20 attempts
not acknowledged before the timeout (including exponential backoff) was
sufficient, despite the heavy load.
The time wasted here sleeping is mitigated by the fact that, later on,
the system will likely wait for the canceled task, causing it to
indefinitely yield until the canceled task finishes, and the task must
acknowledge the cancel before it proceeds to that point.
Now, before a syscall is entered, beginSyscall is called, which may
return error.Canceled. After syscall returns, whether error or success,
endSyscall is called. If the syscall returns EINTR then checkCancel is
called.
`cancelRequested` is removed from the std.Io VTable for now, with plans
to replace it with a more powerful API that allows protection against
cancellation requests.
closes#25751
The inverse MixColumns operation is already used internally for
AES decryption, but it wasn’t exposed in the public API because
it didn’t seem necessary at the time.
Since then, several new AES-based block ciphers and permutations
(such as Vistrutah and Areion) have been developed, and they require
this operation to be implementable in Zig.
Since then, new interesting AES-based block ciphers and permutations
(Vistrutah, Areion, etc). have been invented, and require that
operation to be implementable in Zig.
Rewrite `Reader.takeLeb128` to not use `takeMultipleOf7Leb128` and
instead:
* Use byte aligned integers
* Turn the main reading loop into an inlined loop of static length
* Special case small integers (<= 7 bits)
Notably signed and unsigned 32 bit integers have 5x to 12x(!)
performance improvement.
Outside of that:
For u8, u16 and u64 performance increases ~1.5x to ~6x
For i8, i16 and i64 performance increases ~1.5x to ~3.5x
For integers with bit multiples of 7 performance is roughly equal within the
margin or error.
Also expand on test coverage
Microbenchmark: https://zigbin.io/242cb1
Rewrite `writeLeb128` to no longer use `writeMultipleOf7Leb128` and instead:
* Make use of byte aligned ints
* Special case small numbers (fitting inside 7 bits)
Amongst u8, u16, u32 and u64 performance gains are between ~1.5x and ~2x
Amongst i8, i16, i32 ane i64 perfromance gains are between ~2x and >4x
Additinally add test coverage for written encodings
Microbenchmark: https://zigbin.io/7ed5fe
Hybrid KEMs combine a post-quantum secure KEM with a traditional
elliptic curve Diffie-Hellman key exchange.
The hybrid construction provides security against both classical and quantum
adversaries: even if one component is broken, the combined scheme remains
secure as long as the other component holds.
The implementation follows the IETF CFRG draft specification for concrete
hybrid KEMs:
https://datatracker.ietf.org/doc/draft-irtf-cfrg-concrete-hybrid-kems/
KangarooTwelve is a family of two fast and secure extendable-output
functions (XOFs): KT128 and KT256. These functions generalize
traditional hash functions by allowing arbitrary output lengths.
KangarooTwelve was designed by SHA-3 authors. It aims to deliver
higher performance than the SHA-3 and SHAKE functions defined in
FIPS 202, while preserving their flexibility and core security
principles.
On high-end platforms, it can take advantage of parallelism,
whether through multiple CPU cores or SIMD instructions.
As modern SHA-3 constructions, KT128 and KT256 can serve as
general-purpose hash functions and can be used, for example, in
key-derivation, and with arbitrarily large inputs.
RFC9861: https://datatracker.ietf.org/doc/rfc9861/
It seems to me this was simply forgotten.
Or there is some reason I don't know why this code doesn't work for `comptime_float`.
For a more comprehensive fix, https://github.com/ziglang/zig/pull/24057 is the place to look.
This method is called on an identifier token, so let's rename the parameter to make this clear.
This is also how it's named on most of the caller's sides.
This also unifies the rename implementations, since previously `posix.renameW` used `MoveFileEx` while `posix.renameatW` used `NtOpenFile`/`NtSetInformationFile`. This, in turn, allows the `MoveFileEx` bindings to be deleted as `posix.renameW` was the only usage.
This functionality -- if it's actually needed -- can be reintroduced through
some other mechanism. An ABI is clearly not the right way to represent it.
closes#25918
The new builtins are:
* `@EnumLiteral`
* `@Int`
* `@Fn`
* `@Pointer`
* `@Tuple`
* `@Enum`
* `@Union`
* `@Struct`
Their usage is documented in the language reference.
There is no `@Array` because arrays can be created like this:
if (sentinel) |s| [n:s]T else [n]T
There is also no `@Float`. Instead, `std.meta.Float` can serve this use
case if necessary.
There is no `@ErrorSet` and intentionally no way to achieve this.
Likewise, there is intentionally no way to reify tuples with comptime
fields, or function types with comptime parameters. These decisions
simplify the Zig language specification, and moreover make Zig code more
readable by discouraging overly complex metaprogramming.
Co-authored-by: Ali Cheraghi <alichraghi@proton.me>
Resolves: #10710
If a Reader implementation implements `stream` by ignoring the Writer, writing directly to its internal buffer, and returning 0, then `defaultDiscard` would not update `seek` and also return 0, which is incorrect and can cause `discardShort` to violate the contract of `VTable.discard` by calling into `vtable.discard` with a non-empty buffer.
This commit fixes the problem by advancing seek up to the limit after the stream call. This logic could likely be somewhat simplified in the future depending on how #25170 is resolved.
Andrew Kelley