ladybird/AK/Find.h
Lenny Maiorani 4333a9a8d6 AK: Find a value in any container offering iterators
Problem:
- `find` is implemented inside of each container. This coupling
  requires that each container needs to individually provide `find`.

Solution:
- Decouple the `find` functionality from the container. This allows
  provides a `find` algorithm which can work with all
  containers. Containers can still provide their own `find` in the
  case where it can be optimized.
- This also allows for searching sub-ranges of a container rather than
  the entire container as some of the container-specific member
  functions enforced.

Note:
- @davidstone's talk from 2015 C++Now conference entitled "Functions
  Want to be Free" encourages this style:
  (https://www.youtube.com/watch?v=_lVlC0xzXDc), but it does come at
  the cost of composability.
- A logical follow-on to this is to provide a mechanism to use a
  short-hand function which automatically searches the entire
  container. This could automatically use the container-provided
  version if available so that functions which provide their own
  optimized version get the benefit.
2021-01-11 19:45:05 +01:00

58 lines
2.1 KiB
C++

/*
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#pragma once
#include <AK/Traits.h>
#include <AK/Types.h>
namespace AK {
template<typename TIterator, typename TUnaryPredicate>
constexpr TIterator find_if(TIterator first, TIterator last, TUnaryPredicate&& pred)
{
for (; first != last; ++first) {
if (pred(*first)) {
return first;
}
}
return last;
}
template<typename TIterator, typename T>
constexpr TIterator find(TIterator first, TIterator last, const T& value)
{
return find_if(first, last, [&](const auto& v) { return Traits<T>::equals(value, v); });
}
template<typename TIterator, typename T>
constexpr size_t find_index(TIterator first, TIterator last, const T& value)
{
return find_if(first, last, [&](const auto& v) { return Traits<T>::equals(value, v); }).index();
}
}