BLI: improve support for generic algorithms with c++ containers

Some generic algorithms from the standard library like `std::any_of`
did not work with all container and iterator types. To improve the
situation, this patch adds various type members to containers
and iterators.

Custom iterators for Set, Map and IndexRange now have an iterator
category, which soe algorithms require. IndexRange could become
a random access iterator, but adding all the missing methods can
be done when it is necessary.

1 files changed, 34 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_set.hh b/source/blender/blenlib/BLI_set.hh
index 06b56c3f8e5..fef657b2d8f 100644
--- a/source/blender/blenlib/BLI_set.hh
+++ b/source/blender/blenlib/BLI_set.hh
@@ -119,6 +119,16 @@ template<
      */
     typename Allocator = GuardedAllocator>
 class Set {
+ public:
+  class Iterator;
+  using value_type = Key;
+  using pointer = Key *;
+  using const_pointer = const Key *;
+  using reference = Key &;
+  using const_reference = const Key &;
+  using iterator = Iterator;
+  using size_type = int64_t;
+
  private:
   /**
    * Slots are either empty, occupied or removed. The number of occupied slots can be computed by
@@ -401,6 +411,13 @@ class Set {
    * also change their hash.
    */
   class Iterator {
+   public:
+    using iterator_category = std::forward_iterator_tag;
+    using value_type = Key;
+    using pointer = const Key *;
+    using reference = const Key &;
+    using difference_type = std::ptrdiff_t;
+
    private:
     const Slot *slots_;
     int64_t total_slots_;
@@ -422,17 +439,34 @@ class Set {
       return *this;
     }
 
+    Iterator operator++(int) const
+    {
+      Iterator copied_iterator = *this;
+      ++copied_iterator;
+      return copied_iterator;
+    }
+
     const Key &operator*() const
     {
       return *slots_[current_slot_].key();
     }
 
+    const Key *operator->() const
+    {
+      return slots_[current_slot_].key();
+    }
+
     friend bool operator!=(const Iterator &a, const Iterator &b)
     {
       BLI_assert(a.slots_ == b.slots_);
       BLI_assert(a.total_slots_ == b.total_slots_);
       return a.current_slot_ != b.current_slot_;
     }
+
+    friend bool operator==(const Iterator &a, const Iterator &b)
+    {
+      return !(a != b);
+    }
   };
 
   Iterator begin() const