bpo-32011: Revert "Issue GH-15480: Remove the deprecated and unused TYPE_INT64 code from marshal." (GH-4381) (#4405)

Simplify the reverted code.

This reverts commit e9bbe8b87ba2874efba0474af5cc7d5941dbf742.
(cherry picked from commit 00987f6230fcdbecc8d9ab4b2b9fae8f99a1a4a9)

1 files changed, 21 insertions, 0 deletions

diff --git a/Python/marshal.c b/Python/marshal.c
index 22ca49c756..91a57c293b 100644
--- a/Python/marshal.c
+++ b/Python/marshal.c
@@ -32,6 +32,9 @@
 #define TYPE_STOPITER           'S'
 #define TYPE_ELLIPSIS           '.'
 #define TYPE_INT                'i'
+/* TYPE_INT64 is not generated anymore.
+   Supported for backward compatibility only. */
+#define TYPE_INT64              'I'
 #define TYPE_FLOAT              'f'
 #define TYPE_BINARY_FLOAT       'g'
 #define TYPE_COMPLEX            'x'
@@ -777,6 +780,19 @@ r_long(RFILE *p)
     return x;
 }
 
+/* r_long64 deals with the TYPE_INT64 code. */
+static PyObject *
+r_long64(RFILE *p)
+{
+    const unsigned char *buffer = (const unsigned char *) r_string(8, p);
+    if (buffer == NULL) {
+        return NULL;
+    }
+    return _PyLong_FromByteArray(buffer, 8,
+                                 1 /* little endian */,
+                                 1 /* signed */);
+}
+
 static PyObject *
 r_PyLong(RFILE *p)
 {
@@ -976,6 +992,11 @@ r_object(RFILE *p)
         R_REF(retval);
         break;
 
+    case TYPE_INT64:
+        retval = r_long64(p);
+        R_REF(retval);
+        break;
+
     case TYPE_LONG:
         retval = r_PyLong(p);
         R_REF(retval);