... and mem.copy operations. Requires slightly larger input buffers than result length. Add helper functions std.mem.alignInBytes and std.mem.alignInSlice.
This is a trivial implementation that just does a or[xor] loop.
However, this pattern is used by virtually all crypto libraries and
in practice, even without assembly barriers, LLVM never turns it into
code with conditional jumps, even if one of the parameters is constant.
This has been verified to still be the case with LLVM 11.0.0.
The new defaults that came in with
644400054c5769a397ded4f569e2ac0600d65305 are nice, however, it is still
possible that someone knows their inputs are always small and wants to
use the simpler implementations. We keep the default to make the choice
at runtime, but expose the linear functions in the public interface of
std.mem.
Also improved the doc comments.
Add check if the type is float. Float byte comparison doesn't work
because +0.0 and -0.0 are considered equal but their byte
representations are not equal.
The high level Allocator interface API functions will now do a
`@returnAddress()` so that stack traces captured by allocator
implementations have a return address that does not include the
Allocator overhead functions. This makes `4` a more reasonable default
for how many stack frames to capture.
`std.GeneralPurposeAllocator` is now available. It is a function that
takes a configuration struct (with default field values) and returns an
allocator. There is a detailed description of this allocator in the
doc comments at the top of the new file.
The main feature of this allocator is that it is *safe*. It
prevents double-free, use-after-free, and detects leaks.
Some deprecation compile errors are removed.
The Allocator interface gains `old_align` as a new parameter to
`resizeFn`. This is useful to quickly look up allocations.
`std.heap.page_allocator` is improved to use mmap address hints to avoid
obtaining the same virtual address pages when unmapping and mapping
pages. The new general purpose allocator uses the page allocator as its
backing allocator by default.
`std.testing.allocator` is replaced with usage of this new allocator,
which does leak checking, and so the LeakCheckAllocator is retired.
stage1 is improved so that the `@typeInfo` of a pointer has a lazy value
for the alignment of the child type, to avoid false dependency loops
when dealing with pointers to async function frames.
The `std.mem.Allocator` interface is refactored to be in its own file.
`std.Mutex` now exposes the dummy mutex with `std.Mutex.Dummy`.
This allocator is great for debug mode, however it needs some work to
have better performance in release modes. The next step will be setting
up a series of tests in ziglang/gotta-go-fast and then making
improvements to the implementation.
* Added `replace` for simple pre-allocated search-and-replace
* Added `replacementSize` for calculating ahead-of-time buffer sizes for
performing a safe search-and-replace
* Added `replaceOwned` for automatically allocating and performing
replacement
