Add _PyDict_FromItems()

python · methane · Mar 1, 2022 · Feb 23, 2022 · Feb 25, 2022 · Feb 25, 2022
commit e7d9ba07b22361413636b88580cfa70d17c2a4f5
diff --git a/Include/internal/pycore_dict.h b/Include/internal/pycore_dict.h
@@ -148,6 +148,10 @@ extern uint64_t _pydict_global_version;
 #define DICT_NEXT_VERSION() (++_pydict_global_version)
 
 PyObject *_PyObject_MakeDictFromInstanceAttributes(PyObject *obj, PyDictValues *values);
+PyObject *_PyDict_FromItems(
+        PyObject *const *keys, Py_ssize_t keys_offset,
+        PyObject *const *values, Py_ssize_t values_offset,
+        Py_ssize_t length);
 
 static inline void
 _PyDictValues_AddToInsertionOrder(PyDictValues *values, Py_ssize_t ix)

@@ -935,26 +935,11 @@ PyObject *
 _PyStack_AsDict(PyObject *const *values, PyObject *kwnames)
 {
     Py_ssize_t nkwargs;
-    PyObject *kwdict;
-    Py_ssize_t i;
 
     assert(kwnames != NULL);
     nkwargs = PyTuple_GET_SIZE(kwnames);
-    kwdict = _PyDict_NewPresized(nkwargs);
-    if (kwdict == NULL) {
-        return NULL;
-    }
-
-    for (i = 0; i < nkwargs; i++) {
-        PyObject *key = PyTuple_GET_ITEM(kwnames, i);
-        PyObject *value = *values++;
-        /* If key already exists, replace it with the new value */
-        if (PyDict_SetItem(kwdict, key, value)) {
-            Py_DECREF(kwdict);
-            return NULL;
-        }
-    }
-    return kwdict;
+    return _PyDict_FromItems(&PyTuple_GET_ITEM(kwnames, 0), 1,
+                             values, 1, nkwargs);
 }
 
 

@@ -123,6 +123,8 @@ As a consequence of this, split keys have a maximum size of 16.
 #include "pycore_pystate.h"       // _PyThreadState_GET()
 #include "stringlib/eq.h"         // unicode_eq()
 
+#include <stdbool.h>
+
 /*[clinic input]
 class dict "PyDictObject *" "&PyDict_Type"
 [clinic start generated code]*/
@@ -600,7 +602,7 @@ _PyDict_CheckConsistency(PyObject *op, int check_content)
 
 
 static PyDictKeysObject*
-new_keys_object(uint8_t log2_size, int unicode)
+new_keys_object(uint8_t log2_size, bool unicode)
 {
     PyDictKeysObject *dk;
     Py_ssize_t usable;
@@ -1561,8 +1563,8 @@ dictresize(PyDictObject *mp, uint8_t log2_newsize, int unicode)
     return 0;
 }
 
-PyObject *
-_PyDict_NewPresized(Py_ssize_t minused)
+static PyObject *
+dict_new_presized(Py_ssize_t minused, bool unicode)
 {
     const uint8_t log2_max_presize = 17;
     const Py_ssize_t max_presize = ((Py_ssize_t)1) << log2_max_presize;
@@ -1583,13 +1585,56 @@ _PyDict_NewPresized(Py_ssize_t minused)
         log2_newsize = estimate_log2_keysize(minused);
     }
 
-    // TODO: Document that this function returns dict optimized for string keys.
-    new_keys = new_keys_object(log2_newsize, 1);
+    new_keys = new_keys_object(log2_newsize, unicode);
     if (new_keys == NULL)
         return NULL;
     return new_dict(new_keys, NULL, 0, 0);
 }
 
+PyObject *
+_PyDict_NewPresized(Py_ssize_t minused)
+{
+    return dict_new_presized(minused, false);
+}
+
+PyObject *
+_PyDict_FromItems(PyObject *const *keys, Py_ssize_t keys_offset,
+                  PyObject *const *values, Py_ssize_t values_offset,
+                  Py_ssize_t length)
+{
+    bool unicode = true;
+    PyObject *const *ks = keys;
+
+    for (Py_ssize_t i = 0; i < length; i++) {
+        if (!PyUnicode_CheckExact(*ks)) {
+            unicode = false;
+            break;
+        }
+        ks += keys_offset;
+    }
+
+    PyObject *dict = dict_new_presized(length, unicode);
+    if (dict == NULL) {
+        return NULL;
+    }
+
+    ks = keys;
+    PyObject *const *vs = values;
+
+    for (Py_ssize_t i = 0; i < length; i++) {
+        PyObject *key = *ks;
+        PyObject *value = *vs;
+        if (PyDict_SetItem(dict, key, value) < 0) {
+            Py_DECREF(dict);
+            return NULL;
+        }
+        ks += keys_offset;
+        vs += values_offset;
+    }
+
+    return dict;
+}
+
 /* Note that, for historical reasons, PyDict_GetItem() suppresses all errors
  * that may occur (originally dicts supported only string keys, and exceptions
  * weren't possible).  So, while the original intent was that a NULL return

@@ -3267,20 +3267,12 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, InterpreterFrame *frame, int thr
         }
 
         TARGET(BUILD_MAP) {
-            Py_ssize_t i;
-            PyObject *map = _PyDict_NewPresized((Py_ssize_t)oparg);
+            PyObject *map = _PyDict_FromItems(
+                    &PEEK(2*oparg), 2,
+                    &PEEK(2*oparg - 1), 2,
+                    oparg);
             if (map == NULL)
                 goto error;
-            for (i = oparg; i > 0; i--) {
-                int err;
-                PyObject *key = PEEK(2*i);
-                PyObject *value = PEEK(2*i - 1);
-                err = PyDict_SetItem(map, key, value);
-                if (err != 0) {
-                    Py_DECREF(map);
-                    goto error;
-                }
-            }
 
             while (oparg--) {
                 Py_DECREF(POP());
@@ -3346,7 +3338,6 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, InterpreterFrame *frame, int thr
         }
 
         TARGET(BUILD_CONST_KEY_MAP) {
-            Py_ssize_t i;
             PyObject *map;
             PyObject *keys = TOP();
             if (!PyTuple_CheckExact(keys) ||
@@ -3355,20 +3346,12 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, InterpreterFrame *frame, int thr
                                  "bad BUILD_CONST_KEY_MAP keys argument");
                 goto error;
             }
-            map = _PyDict_NewPresized((Py_ssize_t)oparg);
+            map = _PyDict_FromItems(
+                    &PyTuple_GET_ITEM(keys, 0), 1,
+                    &PEEK(oparg + 1), 1, oparg);
             if (map == NULL) {
                 goto error;
             }
-            for (i = oparg; i > 0; i--) {
-                int err;
-                PyObject *key = PyTuple_GET_ITEM(keys, oparg - i);
-                PyObject *value = PEEK(i + 1);
-                err = PyDict_SetItem(map, key, value);
-                if (err != 0) {
-                    Py_DECREF(map);
-                    goto error;
-                }
-            }
 
             Py_DECREF(POP());
             while (oparg--) {