While it is already mentioned on the `items` attributes of the structs, it is
interesting to comment in every method potentially invalidating pointers to items
that they may do so.
`ArrayList.ensureTotalCapacityPrecise` uses `Allocator.reallocAtLeast` under
the hood, which can return more than `new_capacity` bytes if `alignment
!= @alignOf(T)`. This implementation of `clone` assures that
the case of `ensureTotalCapacityPrecise` is handled correctly.
Thanks @Vexu and @squeek502 for pointing this out.
initCapacity did and still does use the ensureTotalCapacityPrecise logic because the initial capacity of an ArrayList is not important in terms of how it grows, so allocating a more exact slice up-front allows for saving memory when the array list never exceeds that initial allocation size. There are use cases where this precise capacity is useful outside of the `init` function, though, like in instances where the user does not call the `init` function themselves but otherwise knows that an ArrayList is empty so calling `ensureTotalCapacityPrecise` can give the same memory savings that `initCapacity` would have.
Closes#9775
We already have a LICENSE file that covers the Zig Standard Library. We
no longer need to remind everyone that the license is MIT in every single
file.
Previously this was introduced to clarify the situation for a fork of
Zig that made Zig's LICENSE file harder to find, and replaced it with
their own license that required annual payments to their company.
However that fork now appears to be dead. So there is no need to
reinforce the copyright notice in every single file.
Conflicts:
* doc/langref.html.in
* lib/std/enums.zig
* lib/std/fmt.zig
* lib/std/hash/auto_hash.zig
* lib/std/math.zig
* lib/std/mem.zig
* lib/std/meta.zig
* test/behavior/alignof.zig
* test/behavior/bitcast.zig
* test/behavior/bugs/1421.zig
* test/behavior/cast.zig
* test/behavior/ptrcast.zig
* test/behavior/type_info.zig
* test/behavior/vector.zig
Master branch added `try` to a bunch of testing function calls, and some
lines also had changed how to refer to the native architecture and other
`@import("builtin")` stuff.
I've run into this footgun enough times, nearly every time I want
`ensureUnusedCapacity`, not `ensureCapacity`. This commit deprecates
`ensureCapacity` in favor of `ensureTotalCapacity` and introduces
`ensureUnusedCapacity`.
* std.ArrayList gains `moveToUnmanaged` and dead code
`ArrayListUnmanaged.appendWrite` is deleted.
* emit_h state is attached to Module rather than Compilation.
* remove the implementation of emit-h because it did not properly
integrate with incremental compilation. I will re-implement it
in a follow-up commit.
* Compilation: use the .codegen_failure tag rather than
.dependency_failure tag for when `bin_file.updateDecl` fails.
C backend:
* Use a CValue tagged union instead of strings for C values.
* Cleanly separate state into Object and DeclGen:
- Object is present only when generating a .c file
- DeclGen is present for both generating a .c and .h
* Move some functions into their respective Object/DeclGen namespace.
* Forward decls are managed by the incremental compilation frontend; C
backend no longer renders function signatures based on callsites.
For simplicity, all functions always get forward decls.
* Constants are managed by the incremental compilation frontend. C
backend no longer has a "constants" section.
* Participate in incremental compilation. Each Decl gets an ArrayList
for its generated C code and it is updated when the Decl is updated.
During flush(), all these are joined together in the output file.
* The new CValue tagged union is used to clean up using of assigning to
locals without an additional pointer local.
* Fix bug with bitcast of non-pointers making the memcpy destination
immutable.
* Improve ArrayList & co documentation
- Added doc comments about the validity of references to elements in
an ArrayList and how they may become invalid after resizing operations.
- This should help users avoid footguns in future.
* Improve ArrayListUnmanaged & co's documentation
- Port improved documentation from ArrayList and ArrayList aligned to
their unmanaged counterparts.
- Made documentation for ArrayListUnmanaged & co more inclusive and
up-to-date.
- Made documentation more consistent with `ArrayList`.
* Corrections on ArrayList documentation.
- Remove incorrect/unpreferred wording on ArrayList vs
ArrayListUnmanaged.
- Fix notes about the alignment of ArrayListAligned
- Be more verbose with warnings on when pointers are invalidated.
- Copy+paste a few warnings
* add warning to replaceRange
* revert changes to append documentation
* read directly into the ArrayList buffers.
* respect max_output_bytes
* std.ArrayList:
- make `allocatedSlice` public.
- add `unusedCapacitySlice`.
I removed the Windows implementation of this stuff; I am doing a partial
merge of LemonBoy's patch with the understanding that a later patch can
add the Windows implementation after it is vetted.
Don't use the user-supplied cap as starting point for a resize. Doing so
overallocates memory and thus negates the whole point of specifying a
precise cap value.
`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.
* breaking changes to the API. Some of the weird decisions from before
are changed to what would be more expected.
- `get` returns `?V`, use `getEntry` for the old API.
- `put` returns `!void`, use `fetchPut` for the old API.
* HashMap now has a comptime parameter of whether to store hashes with
entries. AutoHashMap has heuristics on whether to set this parameter.
For example, for integers, it is false, since equality checking is
cheap, but for strings, it is true, since equality checking is
probably expensive.
* The implementation has a separate array for entry_index /
distance_from_start_index. Entries no longer has holes; it is an
ArrayList, and iteration is simpler and more cache coherent.
This is inspired by Python's new dictionaries.
* HashMap is separated into an "unmanaged" and a "managed" API. The
unmanaged API is where the actual implementation is; the managed API
wraps it and provides a more convenient API, storing the allocator.
* Memory usage: When there are less than or equal to 8 entries, HashMap
now incurs only a single pointer-size integer as overhead, opposed to
using an ArrayList.
* Since the entries array is separate from the indexes array, the holes
in the indexes array take up less room than the holes in the entries
array otherwise would. However the entries array also allocates
additional capacity for appending into the array.
* HashMap now maintains insertion order. Deletion performs a "swap
remove". It's now possible to modify the HashMap while iterating.
