Added C++ backend for ArrayForTrees

Author: Kishan-Ved

pydatastructs/linear_data_structures/_backend/cpp/arrays/ArrayForTrees.hpp

@@ -0,0 +1,107 @@
+#ifndef LINEAR_DATA_STRUCTURES_ARRAYFORTREES_HPP
+#define LINEAR_DATA_STRUCTURES_ARRAYFORTREES_HPP
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <structmember.h>
+#include "DynamicOneDimensionalArray.hpp"
+#include "OneDimensionalArray.hpp"
+
+typedef struct {
+    PyObject_HEAD
+} ArrayForTrees;
+
+static void ArrayForTrees_dealloc(ArrayForTrees *self) {
+    Py_TYPE(self)->tp_free(reinterpret_cast<PyObject*>(self));
+}
+
+static PyObject* ArrayForTrees__modify(ArrayForTrees *self) {
+    if(((double)self->_num/(double)self->_size) < self->_load_factor){
+        map<long , long> new_indices;
+
+        // PyObject* arr_new = OneDimensionalArray___new__(self->_dtype, 2*self->_num + 1);
+        // This is how arr_new was made in DynamicOneDimensionalArray__modify() for the exact same line :-
+        long new_size = 2 * self->_num + 1;
+        PyObject** arr_new = reinterpret_cast<PyObject**>(std::malloc(new_size * sizeof(PyObject*)));
+        for( i = 0; i < new_size; i++ ) {
+            Py_INCREF(Py_None);
+            arr_new[i] = Py_None;
+        }
+
+        int j=0;
+        PyObject** _data = self->_one_dimensional_array->_data;
+        for(int i=0; i<=self->_last_pos_filled;i++){
+            if(_data[i] != Py_None){ // Check this line. Python code: if self[i] is not None:
+                Py_INCREF(Py_None); // This was put in DynamicOneDimensionalArray line 116
+                arr_new[j] = _data[i];
+                new_indices[_data[i]->key] = j;
+                j += 1;
+            }
+        }
+        for(int i=0;i<j;i++){
+            if(arr_new[i]->left != Py_None){
+                arr_new[i]->left = new_indices[_data[arr_new[i]->left]->key];
+            }
+            if(arr_new[i]->right != Py_None){
+                arr_new[i]->right = new_indices[_data[arr_new[i]->right]->key];
+            }
+            if(arr_new[i]->parent != Py_None){
+                arr_new[i]->parent = new_indices[_data[arr_new[i]->parent]->key];
+            }
+        }
+        self->_last_pos_filled = j - 1;
+        self->_one_dimensional_array->_data = arr_new;
+        self->_one_dimensional_array->_size = new_size;
+        self->_size = new_size;
+        return reinterpret_cast<PyObject*>(new_indices);
+    }
+    Py_INCREF(Py_None);
+    return Py_None;
+}
+
+static struct PyMethodDef ArrayForTrees_PyMethodDef[] = {
+    {"_modify", (PyCFunction) ArrayForTrees__modify, METH_VARARGS, NULL},
+    {NULL}
+};
+
+static PyTypeObject ArrayForTreesType = {
+    /* tp_name */ PyVarObject_HEAD_INIT(NULL, 0) "ArrayForTrees",
+    /* tp_basicsize */ sizeof(ArrayForTrees),
+    /* tp_itemsize */ 0,
+    /* tp_dealloc */ (destructor) ArrayForTrees_dealloc,
+    /* tp_print */ 0,
+    /* tp_getattr */ 0,
+    /* tp_setattr */ 0,
+    /* tp_reserved */ 0,
+    /* tp_repr */ 0,
+    /* tp_as_number */ 0,
+    /* tp_as_sequence */ 0,
+    /* tp_as_mapping */ 0,
+    /* tp_hash  */ 0,
+    /* tp_call */ 0,
+    /* tp_str */ 0,
+    /* tp_getattro */ 0,
+    /* tp_setattro */ 0,
+    /* tp_as_buffer */ 0,
+    /* tp_flags */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+    /* tp_doc */ 0,
+    /* tp_traverse */ 0,
+    /* tp_clear */ 0,
+    /* tp_richcompare */ 0,
+    /* tp_weaklistoffset */ 0,
+    /* tp_iter */ 0,
+    /* tp_iternext */ 0,
+    /* tp_methods */ ArrayForTrees_PyMethodDef,
+    /* tp_members */ 0,
+    /* tp_getset */ 0,
+    /* tp_base */ &DynamicOneDimensionalArrayType,
+    /* tp_dict */ 0,
+    /* tp_descr_get */ 0,
+    /* tp_descr_set */ 0,
+    /* tp_dictoffset */ 0,
+    /* tp_init */ 0,
+    /* tp_alloc */ 0,
+    /* tp_new */ 0,
+};
+
+#endif

pydatastructs/utils/_backend/cpp/TreeNode.hpp

@@ -10,18 +10,18 @@ typedef struct {
     PyObject_HEAD
     long key;
     long data;
-    PyObject* left;
-    PyObject* right;
+    PyObject* left; // can store None or a number
+    PyObject* right; // can store None or a number
     bool is_root;
     long height;
     PyObject* parent;
     long size;
 } TreeNode;
 
 static void TreeNode_dealloc(TreeNode *self) {
-    // Dealloc left and right TreeNodes
-    TreeNode_dealloc(reinterpret_cast<TreeNode*>(TreeNode->left));
-    TreeNode_dealloc(reinterpret_cast<TreeNode*>(TreeNode->right));
+    // left and right are long values, no need to dealloc for them
+    // TreeNode_dealloc(reinterpret_cast<TreeNode*>(TreeNode->left));
+    // TreeNode_dealloc(reinterpret_cast<TreeNode*>(TreeNode->right));
     // Check if other deallocs are needed using Py_XDECREF
     Py_TYPE(self)->tp_free(reinterpret_cast<PyObject*>(self));
 }