[3.6] closes bpo-42938: Replace snprintf with Python unicode formatting in ctypes param reprs. (GH-24250)

(cherry picked from commit 916610ef90a0d0761f08747f7b0905541f0977c7)

Co-authored-by: Benjamin Peterson <benjamin@python.org>
Rebased for Python 2.7 by Michał Górny <mgorny@gentoo.org>

1 files changed, 24 insertions, 25 deletions

diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 066fefc0cca..421addf3530 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -460,50 +460,51 @@ PyCArg_dealloc(PyCArgObject *self)
 static PyObject *
 PyCArg_repr(PyCArgObject *self)
 {
-    char buffer[256];
     switch(self->tag) {
     case 'b':
     case 'B':
-        sprintf(buffer, "<cparam '%c' (%d)>",
+        return PyString_FromFormat("<cparam '%c' (%d)>",
             self->tag, self->value.b);
-        break;
     case 'h':
     case 'H':
-        sprintf(buffer, "<cparam '%c' (%d)>",
+        return PyString_FromFormat("<cparam '%c' (%d)>",
             self->tag, self->value.h);
-        break;
     case 'i':
     case 'I':
-        sprintf(buffer, "<cparam '%c' (%d)>",
+        return PyString_FromFormat("<cparam '%c' (%d)>",
             self->tag, self->value.i);
-        break;
     case 'l':
     case 'L':
-        sprintf(buffer, "<cparam '%c' (%ld)>",
+        return PyString_FromFormat("<cparam '%c' (%ld)>",
             self->tag, self->value.l);
-        break;
 
 #ifdef HAVE_LONG_LONG
     case 'q':
     case 'Q':
-        sprintf(buffer,
+        return PyString_FromFormat(
             "<cparam '%c' (%" PY_FORMAT_LONG_LONG "d)>",
             self->tag, self->value.q);
-        break;
 #endif
     case 'd':
-        sprintf(buffer, "<cparam '%c' (%f)>",
-            self->tag, self->value.d);
-        break;
-    case 'f':
-        sprintf(buffer, "<cparam '%c' (%f)>",
-            self->tag, self->value.f);
-        break;
-
+    case 'f': {
+        PyObject *f = PyFloat_FromDouble((self->tag == 'f') ? self->value.f : self->value.d);
+        if (f == NULL) {
+            return NULL;
+        }
+        PyObject *r = PyObject_Repr(f);
+        if (r == NULL) {
+            Py_DECREF(f);
+            return NULL;
+        }
+        PyObject *result = PyString_FromFormat(
+            "<cparam '%c' (%s)>", self->tag, PyString_AsString(r));
+        Py_DECREF(r);
+        Py_DECREF(f);
+        return result;
+    }
     case 'c':
-        sprintf(buffer, "<cparam '%c' (%c)>",
+        return PyString_FromFormat("<cparam '%c' (%c)>",
             self->tag, self->value.c);
-        break;
 
 /* Hm, are these 'z' and 'Z' codes useful at all?
    Shouldn't they be replaced by the functionality of c_string
@@ -512,16 +513,14 @@ PyCArg_repr(PyCArgObject *self)
     case 'z':
     case 'Z':
     case 'P':
-        sprintf(buffer, "<cparam '%c' (%p)>",
+        return PyString_FromFormat("<cparam '%c' (%p)>",
             self->tag, self->value.p);
         break;
 
     default:
-        sprintf(buffer, "<cparam '%c' at %p>",
+        return PyString_FromFormat("<cparam '%c' at %p>",
             self->tag, self);
-        break;
     }
-    return PyString_FromString(buffer);
 }
 
 static PyMemberDef PyCArgType_members[] = {