Geometry Nodes: Find in String node

Add a node that finds the number of times a substring occurs in a string,
and the position of the start of the first match.

See the PR description for more rational and details.

Pull Request: https://projects.blender.org/blender/blender/pulls/129270

scripts/startup/bl_ui/node_add_menu_geometry.py

@@ -553,6 +553,7 @@ class NODE_MT_category_GEO_TEXT(Menu):
         node_add_menu.add_node_type(layout, "FunctionNodeSliceString")
         layout.separator()
         node_add_menu.add_node_type(layout, "FunctionNodeStringLength")
+        node_add_menu.add_node_type(layout, "FunctionNodeFindInString")
         node_add_menu.add_node_type(layout, "GeometryNodeStringToCurves")
         node_add_menu.add_node_type(layout, "FunctionNodeValueToString")
         layout.separator()

source/blender/blenkernel/BKE_node.hh

@@ -1412,6 +1412,7 @@ void node_tree_remove_layer_n(bNodeTree *ntree, Scene *scene, int layer_index);
 #define FN_NODE_HASH_VALUE 1245
 #define FN_NODE_INTEGER_MATH 1246
 #define FN_NODE_MATRIX_DETERMINANT 1247
+#define FN_NODE_FIND_IN_STRING 1248
 
 /** \} */
 

source/blender/nodes/NOD_static_types.h

@@ -304,6 +304,7 @@ DefNode(FunctionNode, FN_NODE_SEPARATE_MATRIX, 0, SeparateMatrix, "Separate Matr
 DefNode(FunctionNode, FN_NODE_SEPARATE_TRANSFORM, 0, SeparateTransform, "Separate Transform", "")
 DefNode(FunctionNode, FN_NODE_SLICE_STRING, 0, SliceString, "Slice String", "")
 DefNode(FunctionNode, FN_NODE_STRING_LENGTH, 0, StringLength, "String Length", "")
+DefNode(FunctionNode, FN_NODE_FIND_IN_STRING, 0, FindInString, "Find In String","")
 DefNode(FunctionNode, FN_NODE_TRANSFORM_DIRECTION, 0, TransformDirection, "Transform Direction", "")
 DefNode(FunctionNode, FN_NODE_TRANSFORM_POINT, 0, TransformPoint, "Transform Point", "")
 DefNode(FunctionNode, FN_NODE_TRANSPOSE_MATRIX, 0, TransposeMatrix, "Transpose Matrix", "")

source/blender/nodes/function/CMakeLists.txt

@@ -60,6 +60,7 @@ set(SRC
   nodes/node_fn_transform_point.cc
   nodes/node_fn_transpose_matrix.cc
   nodes/node_fn_value_to_string.cc
+  nodes/node_fn_find_in_string.cc
 
   node_function_util.cc
 

source/blender/nodes/function/nodes/node_fn_find_in_string.cc

@@ -0,0 +1,68 @@
+/* SPDX-FileCopyrightText: 2024 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BLI_string_utf8.h"
+
+#include "node_function_util.hh"
+
+namespace blender::nodes::node_fn_find_in_string_cc {
+
+static void node_declare(NodeDeclarationBuilder &b)
+{
+  b.add_input<decl::String>("String").hide_label();
+  b.add_input<decl::String>("Search");
+  b.add_output<decl::Int>("First Found");
+  b.add_output<decl::Int>("Count");
+}
+
+static int string_find(const StringRef text, const StringRef token)
+{
+  if (text.is_empty() || token.is_empty()) {
+    return 0;
+  }
+  const int pos = text.find(token, 0);
+  size_t r_len_bytes;
+  const int pos_n = BLI_strnlen_utf8_ex(text.data(), pos, &r_len_bytes);
+  return pos_n;
+}
+
+static int string_count(const StringRef text, const StringRef token)
+{
+  if (text.is_empty() || token.is_empty()) {
+    return 0;
+  }
+  int count = 0;
+  const int match_len = token.size();
+  int pos = 0;
+  while ((pos = text.find(token, pos)) != StringRef::not_found) {
+    count++;
+    pos += match_len;
+  }
+  return count;
+}
+
+static void node_build_multi_function(NodeMultiFunctionBuilder &builder)
+{
+  static auto token_position_count = mf::build::SI2_SO2<std::string, std::string, int, int>(
+      "Find in String",
+      [](const std::string &text, const std::string &token, int &first, int &count) -> void {
+        first = string_find(text, token);
+        count = string_count(text, token);
+      });
+
+  builder.set_matching_fn(&token_position_count);
+}
+
+static void node_register()
+{
+  static blender::bke::bNodeType ntype;
+
+  fn_node_type_base(&ntype, FN_NODE_FIND_IN_STRING, "Find in String", NODE_CLASS_CONVERTER);
+  ntype.declare = node_declare;
+  ntype.build_multi_function = node_build_multi_function;
+  blender::bke::node_register_type(&ntype);
+}
+NOD_REGISTER_NODE(node_register)
+
+}  // namespace blender::nodes::node_fn_find_in_string_cc