bpo-30277: Replace _sre.getlower() with _sre.ascii_tolower() and _sre.unicode_tolower(). (#1468)

4 files changed, 83 insertions, 44 deletions

diff --git a/Lib/sre_compile.py b/Lib/sre_compile.py
index d7ee4e8..db8b8a2 100644
--- a/Lib/sre_compile.py
+++ b/Lib/sre_compile.py
@@ -69,13 +69,14 @@ def _compile(code, pattern, flags):
     REPEATING_CODES = _REPEATING_CODES
     SUCCESS_CODES = _SUCCESS_CODES
     ASSERT_CODES = _ASSERT_CODES
-    if (flags & SRE_FLAG_IGNORECASE and
-            not (flags & SRE_FLAG_LOCALE) and
-            flags & SRE_FLAG_UNICODE and
-            not (flags & SRE_FLAG_ASCII)):
-        fixes = _ignorecase_fixes
-    else:
-        fixes = None
+    tolower = None
+    fixes = None
+    if flags & SRE_FLAG_IGNORECASE and not flags & SRE_FLAG_LOCALE:
+        if flags & SRE_FLAG_UNICODE and not flags & SRE_FLAG_ASCII:
+            tolower = _sre.unicode_tolower
+            fixes = _ignorecase_fixes
+        else:
+            tolower = _sre.ascii_tolower
     for op, av in pattern:
         if op in LITERAL_CODES:
             if not flags & SRE_FLAG_IGNORECASE:
@@ -85,7 +86,7 @@ def _compile(code, pattern, flags):
                 emit(OP_LOC_IGNORE[op])
                 emit(av)
             else:
-                lo = _sre.getlower(av, flags)
+                lo = tolower(av)
                 if fixes and lo in fixes:
                     emit(IN_IGNORE)
                     skip = _len(code); emit(0)
@@ -102,16 +103,12 @@ def _compile(code, pattern, flags):
         elif op is IN:
             if not flags & SRE_FLAG_IGNORECASE:
                 emit(op)
-                fixup = None
             elif flags & SRE_FLAG_LOCALE:
                 emit(IN_LOC_IGNORE)
-                fixup = None
             else:
                 emit(IN_IGNORE)
-                def fixup(literal, flags=flags):
-                    return _sre.getlower(literal, flags)
             skip = _len(code); emit(0)
-            _compile_charset(av, flags, code, fixup, fixes)
+            _compile_charset(av, flags, code, tolower, fixes)
             code[skip] = _len(code) - skip
         elif op is ANY:
             if flags & SRE_FLAG_DOTALL:
diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index 7601dc8..b5b7cff 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -883,17 +883,23 @@ class ReTests(unittest.TestCase):
     def test_category(self):
         self.assertEqual(re.match(r"(\s)", " ").group(1), " ")
 
-    def test_getlower(self):
+    @cpython_only
+    def test_case_helpers(self):
         import _sre
-        self.assertEqual(_sre.getlower(ord('A'), 0), ord('a'))
-        self.assertEqual(_sre.getlower(ord('A'), re.LOCALE), ord('a'))
-        self.assertEqual(_sre.getlower(ord('A'), re.UNICODE), ord('a'))
-        self.assertEqual(_sre.getlower(ord('A'), re.ASCII), ord('a'))
-
-        self.assertEqual(re.match("abc", "ABC", re.I).group(0), "ABC")
-        self.assertEqual(re.match(b"abc", b"ABC", re.I).group(0), b"ABC")
-        self.assertEqual(re.match("abc", "ABC", re.I|re.A).group(0), "ABC")
-        self.assertEqual(re.match(b"abc", b"ABC", re.I|re.L).group(0), b"ABC")
+        for i in range(128):
+            c = chr(i)
+            lo = ord(c.lower())
+            self.assertEqual(_sre.ascii_tolower(i), lo)
+            self.assertEqual(_sre.unicode_tolower(i), lo)
+
+        for i in list(range(128, 0x1000)) + [0x10400, 0x10428]:
+            c = chr(i)
+            self.assertEqual(_sre.ascii_tolower(i), i)
+            if i != 0x0130:
+                self.assertEqual(_sre.unicode_tolower(i), ord(c.lower()))
+
+        self.assertEqual(_sre.ascii_tolower(0x0130), 0x0130)
+        self.assertEqual(_sre.unicode_tolower(0x0130), ord('i'))
 
     def test_not_literal(self):
         self.assertEqual(re.search(r"\s([^a])", " b").group(1), "b")
diff --git a/Modules/_sre.c b/Modules/_sre.c
index afb2bce..a86c5f2 100644
--- a/Modules/_sre.c
+++ b/Modules/_sre.c
@@ -274,25 +274,35 @@ _sre_getcodesize_impl(PyObject *module)
 }
 
 /*[clinic input]
-_sre.getlower -> int
+_sre.ascii_tolower -> int
 
     character: int
-    flags: int
     /
 
 [clinic start generated code]*/
 
 static int
-_sre_getlower_impl(PyObject *module, int character, int flags)
-/*[clinic end generated code: output=47eebc4c1214feb5 input=087d2f1c44bbca6f]*/
+_sre_ascii_tolower_impl(PyObject *module, int character)
+/*[clinic end generated code: output=228294ed6ff2a612 input=272c609b5b61f136]*/
 {
-    if (flags & SRE_FLAG_LOCALE)
-        return sre_lower_locale(character);
-    if (flags & SRE_FLAG_UNICODE)
-        return sre_lower_unicode(character);
     return sre_lower(character);
 }
 
+/*[clinic input]
+_sre.unicode_tolower -> int
+
+    character: int
+    /
+
+[clinic start generated code]*/
+
+static int
+_sre_unicode_tolower_impl(PyObject *module, int character)
+/*[clinic end generated code: output=6422272d7d7fee65 input=91d708c5f3c2045a]*/
+{
+    return sre_lower_unicode(character);
+}
+
 LOCAL(void)
 state_reset(SRE_STATE* state)
 {
@@ -2740,7 +2750,8 @@ static PyTypeObject Scanner_Type = {
 static PyMethodDef _functions[] = {
     _SRE_COMPILE_METHODDEF
     _SRE_GETCODESIZE_METHODDEF
-    _SRE_GETLOWER_METHODDEF
+    _SRE_ASCII_TOLOWER_METHODDEF
+    _SRE_UNICODE_TOLOWER_METHODDEF
     {NULL, NULL}
 };
 
diff --git a/Modules/clinic/_sre.c.h b/Modules/clinic/_sre.c.h
index 5278323..8056eda 100644
--- a/Modules/clinic/_sre.c.h
+++ b/Modules/clinic/_sre.c.h
@@ -29,34 +29,59 @@ exit:
     return return_value;
 }
 
-PyDoc_STRVAR(_sre_getlower__doc__,
-"getlower($module, character, flags, /)\n"
+PyDoc_STRVAR(_sre_ascii_tolower__doc__,
+"ascii_tolower($module, character, /)\n"
 "--\n"
 "\n");
 
-#define _SRE_GETLOWER_METHODDEF    \
-    {"getlower", (PyCFunction)_sre_getlower, METH_FASTCALL, _sre_getlower__doc__},
+#define _SRE_ASCII_TOLOWER_METHODDEF    \
+    {"ascii_tolower", (PyCFunction)_sre_ascii_tolower, METH_O, _sre_ascii_tolower__doc__},
 
 static int
-_sre_getlower_impl(PyObject *module, int character, int flags);
+_sre_ascii_tolower_impl(PyObject *module, int character);
 
 static PyObject *
-_sre_getlower(PyObject *module, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
+_sre_ascii_tolower(PyObject *module, PyObject *arg)
 {
     PyObject *return_value = NULL;
     int character;
-    int flags;
     int _return_value;
 
-    if (!_PyArg_ParseStack(args, nargs, "ii:getlower",
-        &character, &flags)) {
+    if (!PyArg_Parse(arg, "i:ascii_tolower", &character)) {
+        goto exit;
+    }
+    _return_value = _sre_ascii_tolower_impl(module, character);
+    if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
     }
+    return_value = PyLong_FromLong((long)_return_value);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(_sre_unicode_tolower__doc__,
+"unicode_tolower($module, character, /)\n"
+"--\n"
+"\n");
+
+#define _SRE_UNICODE_TOLOWER_METHODDEF    \
+    {"unicode_tolower", (PyCFunction)_sre_unicode_tolower, METH_O, _sre_unicode_tolower__doc__},
+
+static int
+_sre_unicode_tolower_impl(PyObject *module, int character);
+
+static PyObject *
+_sre_unicode_tolower(PyObject *module, PyObject *arg)
+{
+    PyObject *return_value = NULL;
+    int character;
+    int _return_value;
 
-    if (!_PyArg_NoStackKeywords("getlower", kwnames)) {
+    if (!PyArg_Parse(arg, "i:unicode_tolower", &character)) {
         goto exit;
     }
-    _return_value = _sre_getlower_impl(module, character, flags);
+    _return_value = _sre_unicode_tolower_impl(module, character);
     if ((_return_value == -1) && PyErr_Occurred()) {
         goto exit;
     }
@@ -690,4 +715,4 @@ _sre_SRE_Scanner_search(ScannerObject *self, PyObject *Py_UNUSED(ignored))
 {
     return _sre_SRE_Scanner_search_impl(self);
 }
-/*[clinic end generated code: output=e6dab3ba8864da9e input=a9049054013a1b77]*/
+/*[clinic end generated code: output=811e67d7f8f5052e input=a9049054013a1b77]*/