[김필모] 11주차 미션 제출 (#118)

Author: why-arong

8th_members/김필모/11주차.md

@@ -0,0 +1,102 @@
+
+# dictionay 타입에 대해서 알아보자
+### dict get
+
+```c
+static inline Py_ssize_t
+dictkeys_get_index(const PyDictKeysObject *keys, Py_ssize_t i)
+{
+    Py_ssize_t s = DK_SIZE(keys);
+    Py_ssize_t ix;
+
+    if (s <= 0xff) {
+        const int8_t *indices = (const int8_t*)(keys->dk_indices);
+        ix = indices[i];
+    }
+    else if (s <= 0xffff) {
+        const int16_t *indices = (const int16_t*)(keys->dk_indices);
+        ix = indices[i];
+    }
+#if SIZEOF_VOID_P > 4
+    else if (s > 0xffffffff) {
+        const int64_t *indices = (const int64_t*)(keys->dk_indices);
+        ix = indices[i];
+    }
+#endif
+    else {
+        const int32_t *indices = (const int32_t*)(keys->dk_indices);
+        ix = indices[i];
+    }
+    assert(ix >= DKIX_DUMMY);
+    return ix;
+}
+```
+
+### dict set
+```c
+static inline void
+dictkeys_set_index(PyDictKeysObject *keys, Py_ssize_t i, Py_ssize_t ix)
+{
+    Py_ssize_t s = DK_SIZE(keys);
+
+    assert(ix >= DKIX_DUMMY);
+
+    if (s <= 0xff) {
+        int8_t *indices = (int8_t*)(keys->dk_indices);
+        assert(ix <= 0x7f);
+        indices[i] = (char)ix;
+    }
+    else if (s <= 0xffff) {
+        int16_t *indices = (int16_t*)(keys->dk_indices);
+        assert(ix <= 0x7fff);
+        indices[i] = (int16_t)ix;
+    }
+#if SIZEOF_VOID_P > 4
+    else if (s > 0xffffffff) {
+        int64_t *indices = (int64_t*)(keys->dk_indices);
+        indices[i] = ix;
+    }
+#endif
+    else {
+        int32_t *indices = (int32_t*)(keys->dk_indices);
+        assert(ix <= 0x7fffffff);
+        indices[i] = (int32_t)ix;
+    }
+}
+```
+
+### dict new
+```c
+static PyObject *
+new_dict(PyDictKeysObject *keys, PyObject **values)
+{
+    PyDictObject *mp;
+    assert(keys != NULL);
+#if PyDict_MAXFREELIST > 0
+    if (numfree) {
+        mp = free_list[--numfree];
+        assert (mp != NULL);
+        assert (Py_IS_TYPE(mp, &PyDict_Type));
+        _Py_NewReference((PyObject *)mp);
+    }
+    else
+#endif
+    {
+        mp = PyObject_GC_New(PyDictObject, &PyDict_Type);
+        if (mp == NULL) {
+            dictkeys_decref(keys);
+            if (values != empty_values) {
+                free_values(values);
+            }
+            return NULL;
+        }
+    }
+    mp->ma_keys = keys;
+    mp->ma_values = values;
+    mp->ma_used = 0;
+    mp->ma_version_tag = DICT_NEXT_VERSION();
+    ASSERT_CONSISTENT(mp);
+    return (PyObject *)mp;
+}
+```
+