workaround for py3.13

Author: chenkovsky

lib/cyac/unicode_portability.c

@@ -9,8 +9,53 @@ extern "C" {
         return 1;
     }
 }
-# elif PY_MINOR_VERSION >= 13
-#define Py_BUILD_CORE
-#include <internal/pycore_unicodeobject.h>
+#elif PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 13
+typedef struct {
+    /*
+       These are either deltas to the character or offsets in
+       _PyUnicode_ExtendedCase.
+    */
+    const int upper;
+    const int lower;
+    const int title;
+    /* Note if more flag space is needed, decimal and digit could be unified. */
+    const unsigned char decimal;
+    const unsigned char digit;
+    const unsigned short flags;
+} _PyUnicode_TypeRecord;
+
+#define EXTENDED_CASE_MASK 0x4000
+#include "./unicodetype_db.h"
+static const _PyUnicode_TypeRecord *
+gettyperecord(Py_UCS4 code)
+{
+    int index;
+
+    if (code >= 0x110000)
+        index = 0;
+    else
+    {
+        index = index1[(code>>SHIFT)];
+        index = index2[(index<<SHIFT)+(code&((1<<SHIFT)-1))];
+    }
+
+    return &_PyUnicode_TypeRecords[index];
+}
+
+static int _PyUnicode_ToLowerFull(Py_UCS4 ch, Py_UCS4 *res)
+{
+    const _PyUnicode_TypeRecord *ctype = gettyperecord(ch);
+
+    if (ctype->flags & EXTENDED_CASE_MASK) {
+        int index = ctype->lower & 0xFFFF;
+        int n = ctype->lower >> 24;
+        int i;
+        for (i = 0; i < n; i++)
+            res[i] = _PyUnicode_ExtendedCase[index + i];
+        return n;
+    }
+    res[0] = ch + ctype->lower;
+    return 1;
+}
 #endif
 #endif