Update pybuffer.i library to use new-style Python buffer C API.

Removed old API altogether as Python 2.7 is now the minimum version
supported and it supports the new-style buffer API.

CHANGES.current

@@ -7,6 +7,9 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.0.0 (in progress)
 ===========================
 
+2018-08-12: gmazzamuto
+            [Python] #1283 Update pybuffer.i library to use new-style Python buffer C API.
+
 2018-08-12: brianhatwood,wsfulton
             [Java] #1303 #1304 Fix crash in directors when using OUTPUT and INOUT typemaps in typemaps.i and
             passing NULL pointers in C++ to director method overloaded and implemented in Java.

Doc/Manual/Python.html

@@ -6272,8 +6272,8 @@ For detailed usage of function annotation, see
 
 
 <p>
-Buffer protocols were revised in Python 3. SWIG also gains a series of
+SWIG has a series of
-new typemaps to support buffer interfaces. These typemap macros are
+typemaps to support buffer interfaces. These typemap macros are
 defined in <tt>pybuffer.i</tt>, which must be included in order to use them.
 By using these typemaps, your wrapped function will be able to
 accept any Python object that exposes a suitable buffer interface.
@@ -6398,7 +6398,7 @@ type.
 This macro maps an object's buffer to a pointer <tt>parm</tt> and a
 size <tt>size_parm</tt>. It is similar to
 <tt>%pybuffer_mutable_binary</tt>, except the
-<tt>%pybuffer_binary</tt> an accept both mutable and immutable
+<tt>%pybuffer_binary</tt> can accept both mutable and immutable
 buffers. As a result, the wrapped function should not modify the buffer.
 </p>
 

Examples/test-suite/python_pybuf.i

@@ -1,6 +1,6 @@
 %module python_pybuf
-%include<pybuffer.i>
+%include <pybuffer.i>
-%include<cstring.i>
+%include <cstring.i>
 /*functions for the test case*/
 %pybuffer_mutable_binary(char *buf1, int len);
 %pybuffer_mutable_string(char *buf2);

Lib/python/pybuffer.i

@@ -15,16 +15,12 @@
 %define %pybuffer_mutable_binary(TYPEMAP, SIZE)
 %typemap(in) (TYPEMAP, SIZE) {
   int res; Py_ssize_t size = 0; void *buf = 0;
-%#if PY_VERSION_HEX < 0x03000000
-  res = PyObject_AsWriteBuffer($input, &buf, &size);
-%#else
   Py_buffer view;
   res = PyObject_GetBuffer($input, &view, PyBUF_WRITABLE);
   size = view.len;
   buf = view.buf;
   PyBuffer_Release(&view);
-%#endif
+  if (res < 0) {
-  if (res<0) {
     PyErr_Clear();
     %argument_fail(res, "(TYPEMAP, SIZE)", $symname, $argnum);
   }
@@ -33,7 +29,7 @@
 }
 %enddef
 
-/* %pybuffer_mutable_string(TYPEMAP, SIZE)
+/* %pybuffer_mutable_string(TYPEMAP)
  *
  * Macro for functions accept mutable zero terminated string pointer.
  * This can be used for both input and output. For example:
@@ -48,19 +44,14 @@
 
 %define %pybuffer_mutable_string(TYPEMAP)
 %typemap(in) (TYPEMAP) {
-  int res; Py_ssize_t size = 0; void *buf = 0;
+  int res; void *buf = 0;
-%#if PY_VERSION_HEX < 0x03000000
-  res = PyObject_AsWriteBuffer($input, &buf, &size);
-%#else
   Py_buffer view;
   res = PyObject_GetBuffer($input, &view, PyBUF_WRITABLE);
-  size = view.len;
   buf = view.buf;
   PyBuffer_Release(&view);
-%#endif
+  if (res < 0) {
-  if (res<0) {
     PyErr_Clear();
-    %argument_fail(res, "(TYPEMAP, SIZE)", $symname, $argnum);
+    %argument_fail(res, "(TYPEMAP)", $symname, $argnum);
   }
   $1 = ($1_ltype) buf;
 }
@@ -83,16 +74,12 @@
 %define %pybuffer_binary(TYPEMAP, SIZE)
 %typemap(in) (TYPEMAP, SIZE) {
   int res; Py_ssize_t size = 0; const void *buf = 0;
-%#if PY_VERSION_HEX < 0x03000000
-  res = PyObject_AsReadBuffer($input, &buf, &size);
-%#else
   Py_buffer view;
   res = PyObject_GetBuffer($input, &view, PyBUF_CONTIG_RO);
   size = view.len;
   buf = view.buf;
   PyBuffer_Release(&view);
-%#endif
+  if (res < 0) {
-  if (res<0) {
     PyErr_Clear();
     %argument_fail(res, "(TYPEMAP, SIZE)", $symname, $argnum);
   }
@@ -101,7 +88,7 @@
 }
 %enddef
 
-/* %pybuffer_string(TYPEMAP, SIZE)
+/* %pybuffer_string(TYPEMAP)
  *
  * Macro for functions accept read only zero terminated string pointer.
  * This can be used for input. For example:
@@ -118,18 +105,13 @@
 
 %define %pybuffer_string(TYPEMAP)
 %typemap(in) (TYPEMAP) {
-  int res; Py_ssize_t size = 0; const void *buf = 0;
+  int res; const void *buf = 0;
-%#if PY_VERSION_HEX < 0x03000000
-  res = PyObject_AsReadBuffer($input, &buf, &size);
-%#else
   Py_buffer view;
   res = PyObject_GetBuffer($input, &view, PyBUF_CONTIG_RO);
-  size = view.len;
   buf = view.buf;
   PyBuffer_Release(&view);
-%#endif
+  if (res < 0) {
-  if (res<0) {
+    %argument_fail(res, "(TYPEMAP)", $symname, $argnum);
-    %argument_fail(res, "(TYPEMAP, SIZE)", $symname, $argnum);
   }
   $1 = ($1_ltype) buf;
 }