`findScalarPos` might do repetitive work, even if using simd. For
example, when searching the string `/abcde/fghijk/lm` for the character
`/`, a 16-byte wide search would yield `1000001000000100` but would only
count the first `1` and re-search the remaining of the string.
When testing locally, the difference was quite significative:
```
count scalar
5737 iterations 522.83us per iterations
0 bytes per iteration
worst: 2370us median: 512us stddev: 107.64us
count v2
38333 iterations 78.03us per iterations
0 bytes per iteration
worst: 713us median: 76us stddev: 10.62us
count scalar v2
99565 iterations 29.80us per iterations
0 bytes per iteration
worst: 41us median: 29us stddev: 1.04us
```
Note that `count v2` is a simpler string search, similar to the
remaining version of the simd approach:
```
pub fn countV2(comptime T: type, haystack: []const T, needle: T) usize {
const n = haystack.len;
if (n < 1) return 0;
var count: usize = 0;
for (haystack[0..n]) |item| {
count += @intFromBool(item == needle);
}
return count;
}
```
Which implies the compiler yields some optimized code for a simpler loop
that is more performant than the `findScalarPos`-based approach, hence
the usage of iterative approach for the remaining of the haystack.
Co-authored-by: StAlKeR7779 <stalkek7779@yandex.ru>
* ELF v1 on powerpc64 is only barely kept on life support in a couple of Linux
distros. I don't anticipate that this will last much longer.
* Most of the Linux world has moved to powerpc64le which requires ELF v2.
* Some Linux distros have even started supporting powerpc64 with ELF v2.
* The BSD world has long since moved to ELF v2.
* We have no actual linking support for ELF v1.
* ELF v1 had confused DWARF register mappings which is becoming a problem in
our DWARF code in std.debug.
It's clear that ELF v1 is on its way out, and we never fully supported it
anyway. So let's not waste any time or energy on it going forward.
closes#5927
FreeBSD doesn't support the same number of platforms as Linux, and even then,
only has usermode emulation for a subset of its supported platforms.
NetBSD's usermode emulation support is apparently just broken at the moment.
Previously, `setAlignment` would set the value to 1 fewer than it should, so if you were intending to set alignment to 8 bytes, it would actually set it to 4 bytes, etc.
This enables depth-related use cases without any dependency on the Walker's internal stack which doesn't always pertain to the actual depth of the current entry (i.e. recursing into a directory immediately affects the stack).
Some decision-making might depend on the level of the traversal, so
it makes sense to expose depth here since it's stable, and not in the
automatic walker where it's not.
This matches all other platforms. Even if this field is defined as 'int'
in the C definition, the expectation is that the full 32-bit unsigned
integer range can be used. In particular this Sigaction initializer in
the new std.debug code was causing a build failure:
```zig
.flags = (posix.SA.SIGINFO | posix.SA.RESTART | posix.SA.RESETHAND)
```
Implements deflate compression from scratch. A history window is kept in
the writer's buffer for matching and a chained hash table is used to
find matches. Tokens are accumulated until a threshold is reached and
then outputted as a block. Flush is used to indicate end of stream.
Additionally, two other deflate writers are provided:
* `Raw` writes only in store blocks (the uncompressed bytes). It
utilizes data vectors to efficiently send block headers and data.
* `Huffman` only performs Huffman compression on data and no matching.
The above are also able to take advantage of writer semantics since they
do not need to keep a history.
Literal and distance code parameters in `token` have also been reworked.
Their parameters are now derived mathematically, however the more
expensive ones are still obtained through a lookup table (expect on
ReleaseSmall).
Decompression bit reading has been greatly simplified, taking advantage
of the ability to peek on the underlying reader. Additionally, a few
bugs with limit handling have been fixed.
