From f7c63792f00ec584799fbc207656cdc6003b1040 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rwgk@yahoo.com>
Date: Wed, 21 Feb 2001 10:00:27 +0000
Subject: [PATCH] map [plain] char '\0' <-> "" (Python string of length 0)

[SVN r9306]
---
 src/conversions.cpp | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/src/conversions.cpp b/src/conversions.cpp
index 66951f2f..f14330bd 100644
--- a/src/conversions.cpp
+++ b/src/conversions.cpp
@@ -162,21 +162,20 @@ unsigned short from_python(PyObject* p, boost::python::type<unsigned short> type
 
 PyObject* to_python(char c)
 {
-  return PyString_FromStringAndSize(&c, 1);
+    if (c == '\0') return PyString_FromString("");
+    return PyString_FromStringAndSize(&c, 1);
 }
 
 char from_python(PyObject* p, boost::python::type<char>)
 {
-    if (! PyString_Check(p)) {
-        PyErr_SetString(PyExc_TypeError, "expected string with exactly one character");
+    int l = -1;
+    if (PyString_Check(p)) l = PyString_Size(p);
+    if (l < 0 || l > 1) {
+        PyErr_SetString(PyExc_TypeError, "expected string of length 0 or 1");
         throw boost::python::argument_error();
     }
-    const char* s = PyString_AsString(p);
-    if (! s || s[0] == '\0' || s[1] != '\0') {
-        PyErr_SetString(PyExc_ValueError, "expected string with exactly one character");
-        throw boost::python::argument_error();
-    }
-    return s[0];
+    if (l == 0) return '\0';
+    return PyString_AsString(p)[0];
 }
 
 PyObject* to_python(unsigned char i)