BLI: add CPPType utility to copy elements to a shorter array

1 files changed, 24 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_cpp_type_make.hh b/source/blender/blenlib/BLI_cpp_type_make.hh
index 2612348075b..b0dbbff7ca8 100644
--- a/source/blender/blenlib/BLI_cpp_type_make.hh
+++ b/source/blender/blenlib/BLI_cpp_type_make.hh
@@ -51,6 +51,17 @@ template<typename T> void copy_assign_indices_cb(const void *src, void *dst, Ind
 
   mask.foreach_index([&](int64_t i) { dst_[i] = src_[i]; });
 }
+template<typename T> void copy_assign_compressed_cb(const void *src, void *dst, IndexMask mask)
+{
+  const T *src_ = static_cast<const T *>(src);
+  T *dst_ = static_cast<T *>(dst);
+
+  mask.to_best_mask_type([&](auto best_mask) {
+    for (const int64_t i : IndexRange(best_mask.size())) {
+      dst_[i] = src_[best_mask[i]];
+    }
+  });
+}
 
 template<typename T> void copy_construct_cb(const void *src, void *dst)
 {
@@ -63,6 +74,17 @@ template<typename T> void copy_construct_indices_cb(const void *src, void *dst,
 
   mask.foreach_index([&](int64_t i) { new (dst_ + i) T(src_[i]); });
 }
+template<typename T> void copy_construct_compressed_cb(const void *src, void *dst, IndexMask mask)
+{
+  const T *src_ = static_cast<const T *>(src);
+  T *dst_ = static_cast<T *>(dst);
+
+  mask.to_best_mask_type([&](auto best_mask) {
+    for (const int64_t i : IndexRange(best_mask.size())) {
+      new (dst_ + i) T(src_[best_mask[i]]);
+    }
+  });
+}
 
 template<typename T> void move_assign_cb(void *src, void *dst)
 {
@@ -208,10 +230,12 @@ CPPType::CPPType(CPPTypeParam<T, Flags> /* unused */, StringRef debug_name)
   if constexpr (std::is_copy_assignable_v<T>) {
     copy_assign_ = copy_assign_cb<T>;
     copy_assign_indices_ = copy_assign_indices_cb<T>;
+    copy_assign_compressed_ = copy_assign_compressed_cb<T>;
   }
   if constexpr (std::is_copy_constructible_v<T>) {
     copy_construct_ = copy_construct_cb<T>;
     copy_construct_indices_ = copy_construct_indices_cb<T>;
+    copy_construct_compressed_ = copy_construct_compressed_cb<T>;
   }
   if constexpr (std::is_move_assignable_v<T>) {
     move_assign_ = move_assign_cb<T>;