BLI: move generic data structures to blenlib

This is a follow up to rB2252bc6a5527cd7360d1ccfe7a2d1bc640a8dfa6.

source/blender/blenlib/intern/generic_vector_array.cc

@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BLI_generic_vector_array.hh"
+
+namespace blender {
+
+GVectorArray::GVectorArray(const CPPType &type, const int64_t array_size)
+    : type_(type), element_size_(type.size()), items_(array_size)
+{
+}
+
+GVectorArray::~GVectorArray()
+{
+  if (type_.is_trivially_destructible()) {
+    return;
+  }
+  for (Item &item : items_) {
+    type_.destruct_n(item.start, item.length);
+  }
+}
+
+void GVectorArray::append(const int64_t index, const void *value)
+{
+  Item &item = items_[index];
+  if (item.length == item.capacity) {
+    this->realloc_to_at_least(item, item.capacity + 1);
+  }
+
+  void *dst = POINTER_OFFSET(item.start, element_size_ * item.length);
+  type_.copy_construct(value, dst);
+  item.length++;
+}
+
+void GVectorArray::extend(const int64_t index, const GVArray &values)
+{
+  BLI_assert(values.type() == type_);
+  for (const int i : IndexRange(values.size())) {
+    BUFFER_FOR_CPP_TYPE_VALUE(type_, buffer);
+    values.get(i, buffer);
+    this->append(index, buffer);
+    type_.destruct(buffer);
+  }
+}
+
+void GVectorArray::extend(const int64_t index, const GSpan values)
+{
+  this->extend(index, GVArray::ForSpan(values));
+}
+
+void GVectorArray::extend(IndexMask mask, const GVVectorArray &values)
+{
+  for (const int i : mask) {
+    GVArray_For_GVVectorArrayIndex array{values, i};
+    this->extend(i, GVArray(&array));
+  }
+}
+
+void GVectorArray::extend(IndexMask mask, const GVectorArray &values)
+{
+  GVVectorArray_For_GVectorArray virtual_values{values};
+  this->extend(mask, virtual_values);
+}
+
+void GVectorArray::clear(IndexMask mask)
+{
+  for (const int64_t i : mask) {
+    Item &item = items_[i];
+    type_.destruct_n(item.start, item.length);
+    item.length = 0;
+  }
+}
+
+GMutableSpan GVectorArray::operator[](const int64_t index)
+{
+  Item &item = items_[index];
+  return GMutableSpan{type_, item.start, item.length};
+}
+
+GSpan GVectorArray::operator[](const int64_t index) const
+{
+  const Item &item = items_[index];
+  return GSpan{type_, item.start, item.length};
+}
+
+void GVectorArray::realloc_to_at_least(Item &item, int64_t min_capacity)
+{
+  const int64_t new_capacity = std::max(min_capacity, item.length * 2);
+
+  void *new_buffer = allocator_.allocate(element_size_ * new_capacity, type_.alignment());
+  type_.relocate_assign_n(item.start, new_buffer, item.length);
+
+  item.start = new_buffer;
+  item.capacity = new_capacity;
+}
+
+}  // namespace blender