In Linux when writing to various files in the virtual file system,
for example /sys/fs/cgroup, if you write an invalid value to a file
you'll get errno 16.
This change allows for these specific cases to be caught instead of
being lumped together in UnexpectedError.
Previously, this API had pid, to be used on POSIX systems, and handle,
to be used on Windows.
This commit unifies the API, defining an Id type that is either the pid
or the HANDLE depending on the target OS.
This commit also prepares for the future by allowing one to import via
`std.process.Child` which is the fully qualified namespace that I intend
to migrate to in the future.
Also add `std.fs.has_executable_bit` for doing conditional compilation.
This adds the linux syscalls for chmod and fchmodat, as well as the
extern libc function declarations.
Only `fchmodat` is added to `std.os`, and it is not yet added to std.fs.
Make the Keccak permutation public, as it's useful for more than
SHA-3 (kMAC, SHAKE, TurboSHAKE, TupleHash, etc).
Our Keccak implementation was accepting f as a comptime parameter,
but always used 64-bit words and 200 byte states, so it actually
didn't work with anything besides f=1600.
That has been fixed. The ability to use reduced-round versions
was also added in order to support M14 and K12.
The state was constantly converted back and forth between bytes
and words, even though only a part of the state is actually used
for absorbing and squeezing bytes. It was changed to something
similar to the other permutations we have, so we can avoid extra
copies, and eventually add vectorized implementations.
In addition, the SHAKE extendable output function (XOF) was
added (SHAKE128, SHAKE256). It is required by newer schemes,
such as the Kyber post-quantum key exchange mechanism, whose
implementation is currently blocked by SHAKE missing from our
standard library.
Breaking change: `Keccak_256` and `Keccak_512` were renamed to
`Keccak256` and `Keccak512` for consistency with all other
hash functions.
And make it not do any installation, only objcopying. We already have
install steps for doing installation.
This commit also makes ObjCopyStep properly integrate with caching.
And additionally support writing files to source files. This means a
custom build step in zig's own build.zig is no longer needed for copying
zig.h because it is handled by WriteFileStep.
Forcing the key to be of the same type as the sorted items used during
the search is a valid use case.
There, however, exists some cases where the key and the items are of
heterogeneous types, like searching for a code point in ordered ranges
of code points:
```zig
const CodePoint = u21;
const CodePointRange = [2]CodePoint;
const valid_ranges = &[_]CodePointRange{
// an ordered array of ranges
};
fn orderCodePointAndRange(
context: void,
code_point: CodePoint,
range: CodePointRange
) std.math.Order {
_ = context;
if (code_point < range[0]) {
return .lt;
}
if (code_point > range[1]) {
return .gt;
}
return .eq;
}
fn isValidCodePoint(code_point: CodePoint) bool {
return std.sort.binarySearch(
CodePointRange,
code_point,
valid_ranges,
void,
orderCodePointAndRange
) != null;
}
```
It is so expected that `std.sort.binarySearch` should therefore support
both homogeneous and heterogeneous keys.
Previously `executeSequenceRingBuffer()` would not verify the offset
against the number of bytes already decoded, so it would happily copy
garbage bytes rather than return an error before the window was filled.
To fix this a new `written_count` is added to the decode state that
tracks the total number of bytes decoded.
