Add CPP version of bubble sort (#540)

Author: sak-codes

pydatastructs/linear_data_structures/_backend/cpp/algorithms/algorithms.cpp

@@ -1,9 +1,12 @@
 #include <Python.h>
 #include "quick_sort.hpp"
+#include "bubble_sort.hpp"
 
 static PyMethodDef algorithms_PyMethodDef[] = {
     {"quick_sort", (PyCFunction) quick_sort,
      METH_VARARGS | METH_KEYWORDS, ""},
+    {"bubble_sort", (PyCFunction) bubble_sort,
+     METH_VARARGS | METH_KEYWORDS, ""},
     {NULL, NULL, 0, NULL}        /* Sentinel */
 };
 

pydatastructs/linear_data_structures/_backend/cpp/algorithms/bubble_sort.hpp

@@ -0,0 +1,68 @@
+#ifndef LINEAR_DATA_STRUCTURES_ALGORITHMS_BUBBLE_SORT_HPP
+#define LINEAR_DATA_STRUCTURES_ALGORITHMS_BUBBLE_SORT_HPP
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include "../arrays/OneDimensionalArray.hpp"
+#include "../arrays/DynamicOneDimensionalArray.hpp"
+#include "../../../../utils/_backend/cpp/utils.hpp"
+
+static PyObject* bubble_sort_impl(PyObject* array, size_t lower, size_t upper,
+    PyObject* comp, size_t arr_length) {
+    for (size_t i = 0; i < arr_length - 1; i++) {
+        for (size_t j = lower; j < upper; j++) {
+            PyObject* j_PyObject = PyLong_FromSize_t(j);
+            PyObject* j1_PyObject = PyLong_FromSize_t(j+1);
+            if( _comp(PyObject_GetItem(array, j_PyObject),
+                        PyObject_GetItem(array, j1_PyObject), comp) != 1 ) {
+                PyObject* tmp = PyObject_GetItem(array, j1_PyObject);
+                PyObject_SetItem(array, j1_PyObject,
+                                PyObject_GetItem(array, j_PyObject));
+                PyObject_SetItem(array, j_PyObject, tmp);
+            }
+        }
+    }
+    return array;
+}
+
+
+static PyObject* bubble_sort(PyObject* self, PyObject* args, PyObject* kwds) {
+    PyObject *args0 = NULL, *start = NULL, *end = NULL;
+    PyObject *comp = NULL, *pick_pivot_element = NULL;
+    size_t lower, upper, arr_length;
+    args0 = PyObject_GetItem(args, PyZero);
+    int is_DynamicOneDimensionalArray = _check_type(args0, &DynamicOneDimensionalArrayType);
+    int is_OneDimensionalArray = _check_type(args0, &OneDimensionalArrayType);
+    if( !is_DynamicOneDimensionalArray && !is_OneDimensionalArray ) {
+        raise_exception_if_not_array(args0);
+        return NULL;
+    }
+    comp = PyObject_GetItem(kwds, PyUnicode_FromString("comp"));
+    if( comp == NULL ) {
+        PyErr_Clear();
+    }
+    start = PyObject_GetItem(kwds, PyUnicode_FromString("start"));
+    if( start == NULL ) {
+        PyErr_Clear();
+        lower = 0;
+    } else {
+        lower = PyLong_AsSize_t(start);
+    }
+    end = PyObject_GetItem(kwds, PyUnicode_FromString("end"));
+    if( end == NULL ) {
+        PyErr_Clear();
+        upper = PyObject_Length(args0) - 1;
+    } else {
+        upper = PyLong_AsSize_t(end);
+    }
+    arr_length = PyObject_Length(args0);
+
+    args0 = bubble_sort_impl(args0, lower, upper, comp, arr_length);
+    if( is_DynamicOneDimensionalArray ) {
+        PyObject_CallMethod(args0, "_modify", "O", Py_True);
+    }
+    Py_INCREF(args0);
+    return args0;
+}
+
+#endif

pydatastructs/linear_data_structures/algorithms.py

@@ -1361,8 +1361,9 @@ def bubble_sort(array, **kwargs):
 
     .. [1] https://en.wikipedia.org/wiki/Bubble_sort
     """
-    raise_if_backend_is_not_python(
-            bubble_sort, kwargs.get('backend', Backend.PYTHON))
+    backend = kwargs.pop("backend", Backend.PYTHON)
+    if backend == Backend.CPP:
+        return _algorithms.bubble_sort(array, **kwargs)
     start = kwargs.get('start', 0)
     end = kwargs.get('end', len(array) - 1)
     comp = kwargs.get("comp", lambda u, v: u <= v)

pydatastructs/linear_data_structures/tests/benchmarks/test_algorithms.py

@@ -1,6 +1,6 @@
 import random, timeit, functools, os, pytest
 from pydatastructs import (OneDimensionalArray, Backend,
-    DynamicOneDimensionalArray, quick_sort)
+    DynamicOneDimensionalArray, quick_sort, bubble_sort)
 
 def _test_common_sort(sort, **kwargs):
     cpp = Backend.CPP
@@ -34,3 +34,8 @@ def _common(array_type, dtype, *args, **kwargs):
 @pytest.mark.xfail
 def test_quick_sort():
     _test_common_sort(quick_sort, size=4000)
+
+
+@pytest.mark.xfail
+def test_bubble_sort():
+    _test_common_sort(bubble_sort, size=2000)

pydatastructs/linear_data_structures/tests/test_algorithms.py

@@ -117,6 +117,7 @@ def test_quick_sort():
 
 def test_bubble_sort():
     _test_common_sort(bubble_sort)
+    _test_common_sort(bubble_sort, backend=Backend.CPP)
 
 def test_selection_sort():
     _test_common_sort(selection_sort)