SipHash is highly HashDoS-resistent, initialized with a random seed at
startup (i.e. non-deterministic) and usable for security-critical use
cases with large enough parameters. We just use it because it's
reasonably secure with parameters 1-3 while having excellent properties
and not being significantly slower than before.
There was a small mishmash of argument order, as seen on the table:
| Traits<T>::equals(U, T) | Traits<T>::equals(T, U)
============= | ======================= | =======================
uses equals() | HashMap | Vector, HashTable
defines equals() | *String[^1] | ByteBuffer
[^1]: String, DeprecatedString, their Fly-type equivalents and KString.
This mostly meant that you couldn't use a StringView for finding a value
in Vector<String>.
I'm changing the order of arguments to make the trait type itself first
(`Traits<T>::equals(T, U)`), as I think it's more expected and makes us
more consistent with the rest of the functions that put the stored type
first (like StringUtils functions and binary_serach). I've also renamed
the variable name "other" in find functions to "entry" to give more
importance to the value.
With this change, each of the following lines will now compile
successfully:
Vector<String>().contains_slow("WHF!"sv);
HashTable<String>().contains("WHF!"sv);
HashMap<ByteBuffer, int>().contains("WHF!"sv.bytes());
This underlines that we still copy-construct and copy-assign HashMaps.
Primarily, this makes it easier to develop towards OOM-safe(r) internal
data structures, by providing a reminder (the FIXME) and an easy error-
checking switch (just change it to "delete" to see some of the errors).
This patch adds the `USING_AK_GLOBALLY` macro which is enabled by
default, but can be overridden by build flags.
This is a step towards integrating Jakt and AK types.
Just walk the table from start to finish, deleting buckets as we go.
This removes the need for remove() to return an iterator, which is
preventing me from implementing hash table auto-shrinking.
This will allow us to avoid some potentially expensive type conversion
during lookup, like form String to StringView, which would allocate
memory otherwise.
This was required before commit 5f724b6ca1
when we were building LibC before libstdc++ headers were available in
the sysroot. However as noted in that commit, we never actually needed
to be building LibC before libstdc++, so we can go ahead and remove this
ancient hack.
This function ensures that a key is present in the HashMap.
If it's not present, it is inserted, and the corresponding value
is initialized with whatever the callback returns.
It allows us to express this:
auto it = map.find(key);
if (it == map.end()) {
map.set(it, make_a_value());
it = map.find(key);
}
auto& value = it->value;
Like this:
auto& value = map.ensure(key, [] { return make_a_value(); });
Note that the callback is only invoked if we have to insert a missing
key into the HashMap. This is important in case constructing the default
value is expensive or otherwise undesirable.
Additionally, the const version of get() returns Optional<ConstPeekType>
for smart pointers.
For example, if the value in the HashMap is OwnPtr<u32>,
HashMap::get() const returns Optional<const u32*>.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
Arbitrarily split up to make git bisect easier.
These unnecessary #include's were found by combining an automated tool (which
determined likely candidates) and some brain power (which decided whether
the #include is also semantically superfluous).
Problem:
- Many constructors are defined as `{}` rather than using the ` =
default` compiler-provided constructor.
- Some types provide an implicit conversion operator from `nullptr_t`
instead of requiring the caller to default construct. This violates
the C++ Core Guidelines suggestion to declare single-argument
constructors explicit
(https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c46-by-default-declare-single-argument-constructors-explicit).
Solution:
- Change default constructors to use the compiler-provided default
constructor.
- Remove implicit conversion operators from `nullptr_t` and change
usage to enforce type consistency without conversion.
