revert old PyLongExport & return type for PyLong_Export :(

Author: skirpichev

peps/pep-0757.rst

@@ -107,39 +107,52 @@ Export API
 
    Export of a Python :class:`int` object.
 
-   .. c:struct:: digit_array
+   There are two cases:
 
-      Export an integer as an array of digits; corresponds to
-      :c:macro:`!PyLongExport_DigitArray` export type.
+   * If :c:member:`digits` is ``NULL``, only use the :c:member:`value` member.
+     Calling :c:func:`PyLong_FreeExport` is optional in this case.
+   * If :c:member:`digits` is not ``NULL``, use :c:member:`negative`,
+     :c:member:`ndigits` and :c:member:`digits` members.
+     Calling :c:func:`PyLong_FreeExport` is mandatory in this case.
 
-      .. c:member:: Py_ssize_t ndigits
+   .. c:member:: int64_t value
 
-         Number of digits in :c:member:`digits` array.
+      The native integer value of the exported :class:`int` object.
+      Only valid if :c:member:`digits` is ``NULL``.
 
-      .. c:member:: const void *digits
+   .. c:member:: uint8_t negative
 
-         Read-only array of unsigned digits.
+      1 if the number is negative, 0 otherwise.
+      Only valid if :c:member:`digits` is not ``NULL``.
 
-      .. c:member:: uint8_t negative
+   .. c:member:: Py_ssize_t ndigits
 
-         1 if the number is negative, 0 otherwise.
+      Number of digits in :c:member:`digits` array.
+      Only valid if :c:member:`digits` is not ``NULL``.
+
+   .. c:member:: const void *digits
+
+      Read-only array of unsigned digits. Can be ``NULL``.
+
+   If :c:member:`digits` not ``NULL``, a private field of the
+   :c:struct:`PyLongExport` structure stores a strong reference to the Python
+   :class:`int` object to make sure that that structure remains valid until
+   :c:func:`PyLong_FreeExport()` is called.
 
 
 .. c:function:: int PyLong_Export(PyObject *obj, PyLongExport *export)
 
    Export a Python :class:`int` object.
 
-   On success, set *\*export* and return an appropriate export type
-   for the given value, see the :c:struct:`PyLongExport` struct.
-   :c:func:`PyLong_FreeExport` must be called when the export is no
-   longer needed.  Currently the only available type is
-   :c:macro:`!PyLongExport_DigitArray`.
-
-   On error, set an exception and return :c:macro:`!PyLongExport_Error`.
+   On success, set *\*export* and return 0.
+   On error, set an exception and return -1.
 
    This function always succeeds if *obj* is a Python :class:`int` object or a
    subclass.
 
+   If *export->digits* is not ``NULL``, :c:func:`PyLong_FreeExport` must be
+   called when the export is no longer needed.
+
 
 On CPython 3.14, no memory copy is needed in :c:func:`PyLong_Export`, it's just
 a thin wrapper to expose Python :class:`int` internal digits array.
@@ -254,29 +267,32 @@ Code::
     static void
     mpz_set_PyLong(mpz_t z, PyObject *obj)
     {
-        int overflow;
-        long value = PyLong_AsLongAndOverflow(obj, &overflow);
-
-        if (!overflow) {
-            mpz_set_si(z, value);
+        static PyLongExport long_export;
+
+        PyLong_Export(obj, &long_export);
+        if (long_export.digits) {
+            mpz_import(z, long_export.ndigits, int_digits_order, int_digit_size,
+                       int_endianness, int_nails, long_export.digits);
+            if (long_export.negative) {
+                mpz_neg(z, z);
+            }
+            PyLong_FreeExport(&long_export);
         }
         else {
-            static PyLongExport long_export;
-            const PyLongExport_Kind kind = PyLong_Export(obj, &long_export);
-
-            switch (kind) {
-            case PyLongExport_DigitArray:
-                mpz_import(z, long_export.digit_array.ndigits, int_digits_order,
-                           int_digit_size, int_endianness, int_nails,
-                           long_export.digit_array.digits);
-                if (long_export.digit_array.negative) {
-                    mpz_neg(z, z);
+            const int64_t value = long_export.value;
+
+            if (LONG_MIN <= value && value <= LONG_MAX) {
+                mpz_set_si(z, value);
+            }
+            else {
+                mpz_import(z, 1, -1, sizeof(int64_t), 0, 0, &value);
+                if (value < 0) {
+                    mpz_t tmp;
+                    mpz_init(tmp);
+                    mpz_ui_pow_ui(tmp, 2, 64);
+                    mpz_sub(z, z, tmp);
+                    mpz_clear(tmp);
                 }
-                PyLong_FreeExport(&long_export);
-                break;
-            default:
-                PyLong_FreeExport(&long_export);
-                abort();  /* new CPython release came with a new format */
             }
         }
     }