From 4aaea1cf33192fdff89c31335c07d7526b2fe89b Mon Sep 17 00:00:00 2001
From: Yi Zhang <zhangyiss@icloud.com>
Date: Mon, 20 Jan 2025 17:17:50 +0800
Subject: [PATCH] tmp

---
 lib/io/gmsh_io.h | 108 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)

diff --git a/lib/io/gmsh_io.h b/lib/io/gmsh_io.h
index cb4c7d0..1da881b 100644
--- a/lib/io/gmsh_io.h
+++ b/lib/io/gmsh_io.h
@@ -65,6 +65,7 @@ namespace gctl
 
 		template <typename A> void read_node(array<vertex<point2dc, A>> &out_nodes);
 		template <typename A> void read_node(array<vertex<point3dc, A>> &out_nodes);
+		template <typename E, typename A> void read_element(array<type_edge2d<E>> &out_elements, const array<vertex<point2dc, A>> &nodes, _2i_vector *ele_tag = nullptr);
 		template <typename E, typename A> void read_element(array<type_triangle2d<E>> &out_elements, const array<vertex<point2dc, A>> &nodes, _2i_vector *ele_tag = nullptr);
 		template <typename E, typename A> void read_element(array<type_triangle2d2o<E>> &out_elements, const array<vertex<point2dc, A>> &nodes, _2i_vector *ele_tag = nullptr);
 		template <typename E, typename A> void read_element(array<type_rectangle2d<E>> &out_elements, const array<vertex<point2dc, A>> &nodes, _2i_vector *ele_tag = nullptr);
@@ -151,6 +152,14 @@ namespace gctl
 		return;
 	}
 
+	template <typename E, typename A>
+	void gmshio::read_element(array<type_edge2d<E>> &out_elements, const array<vertex<point2dc, A>> &nodes, _2i_vector *ele_tag)
+	{
+		initialized(Input);
+		read_gmsh_element(gmsh_in, out_elements, nodes, in_packed, ele_tag);
+		return;
+	}
+
 	template <typename E, typename A>
 	void gmshio::read_element(array<type_triangle2d<E>> &out_elements, const array<vertex<point2dc, A>> &nodes, _2i_vector *ele_tag)
 	{
@@ -1135,6 +1144,105 @@ namespace gctl
 		return;
 	}
 
+	/**
+	 * @brief      Read element index from a Gmsh file.
+	 *
+	 * @param[in]  infile       The input file stream
+	 * @param      element      The output element object array
+	 * @param      node         The node array
+	 * @param[in]  packed       Indicates whether the index in the node file starts from zero. The 
+	 * index is deemed to be started with one if this option is false. The default value of this 
+	 * variable is true.
+	 * @param[in]  ele_tag      Return elements' tags by a 2D integer vector.
+	 *
+	 */
+	template <typename E, typename A>
+	void read_gmsh_element(std::ifstream &infile, array<type_edge2d<E>> &element, 
+		const array<vertex<point2dc, A>> &node, index_packed_e packed = Packed, 
+		_2i_vector *ele_tag = nullptr)
+	{
+		if (node.empty())
+			throw runtime_error("The input array is empty. From gctl::read_gmsh_element(...)");
+
+		// 重置数据
+		if (!element.empty()) element.clear();
+		// 重置标签
+		if (ele_tag != nullptr && !ele_tag->empty()) ele_tag->clear();
+
+		// 将文件指针重置到文件头
+		infile.clear(std::ios::goodbit);
+		infile.seekg(std::ios::beg);
+
+		int i_size = 0, ele_count = 0;
+		int tmp_int, ele_type, attri_num;
+		int tmp_index[2];
+		std::string tmp_str;
+		std::stringstream tmp_ss;
+		while(getline(infile,tmp_str))
+		{
+			if (tmp_str == "$Elements") //读入模型空间顶点集 msh文件版本为2.2
+			{
+				getline(infile,tmp_str);
+				gctl::str2ss(tmp_str, tmp_ss);
+				tmp_ss >> i_size; //第一个数为顶点的个数
+
+				// 我们先用一个临时的向量来储存元素
+				edge2d tmp_edge;
+				std::vector<edge2d> element_vec;
+				std::vector<int> tmp_tag;
+
+				for (int i = 0; i < i_size; i++)
+				{
+					getline(infile,tmp_str);
+					str2ss(tmp_str, tmp_ss);
+					tmp_ss >> tmp_int >> ele_type >> attri_num;
+					if (ele_type == 1)
+					{
+						tmp_edge.id = ele_count;
+
+						tmp_tag.clear();
+						for (int a = 0; a < attri_num; a++)
+						{
+							tmp_ss >> tmp_int;
+							tmp_tag.push_back(tmp_int);
+						}
+
+						if (ele_tag != nullptr)
+							ele_tag->push_back(tmp_tag);
+
+						tmp_ss >> tmp_index[0] >> tmp_index[1];
+
+						if (packed == NotPacked)
+						{
+							for (int j = 0; j < 2; j++)
+								tmp_edge.vert[j] = node.get(tmp_index[j]-1);
+						}
+						else
+						{
+							for (int j = 0; j < 2; j++)
+								tmp_edge.vert[j] = node.get(tmp_index[j]);
+						}
+						element_vec.push_back(tmp_edge);
+
+						ele_count++;
+					}
+				}
+
+				//将元素转移到向量上来
+				element.resize(element_vec.size());
+				for (int i = 0; i < element.size(); i++)
+				{
+					element[i].id = element_vec[i].id;
+					for (int j = 0; j < 2; j++)
+						element[i].vert[j] = element_vec[i].vert[j];
+				}
+				destroy_vector(element_vec);
+				break;
+			}
+		}
+		return;
+	}
+
 	/**
 	 * @brief      Read element index from a Gmsh file.
 	 *