5 files changed, 281 insertions, 0 deletions
diff --git a/Examples/python/pointer/Makefile b/Examples/python/pointer/Makefile
new file mode 100644
index 0000000..0f4a1e0
--- /dev/null
+++ b/Examples/python/pointer/Makefile
@@ -0,0 +1,20 @@
+TOP        = ../..
+SWIG       = $(TOP)/../preinst-swig
+SRCS       = example.c
+TARGET     = example
+INTERFACE  = example.i
+
+all::
+	$(MAKE) -f $(TOP)/Makefile SRCS='$(SRCS)' SWIG='$(SWIG)' \
+	TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' python
+
+static::
+	$(MAKE) -f $(TOP)/Makefile SRCS='$(SRCS)' SWIG='$(SWIG)' \
+	TARGET='mypython' INTERFACE='$(INTERFACE)' python_static
+
+clean::
+	$(MAKE) -f $(TOP)/Makefile python_clean
+	rm -f $(TARGET).py
+
+check: all
+	$(MAKE) -f $(TOP)/Makefile python_run
diff --git a/Examples/python/pointer/example.c b/Examples/python/pointer/example.c
new file mode 100644
index 0000000..b877d9a
--- /dev/null
+++ b/Examples/python/pointer/example.c
@@ -0,0 +1,16 @@
+/* File : example.c */
+
+void add(int *x, int *y, int *result) {
+  *result = *x + *y;
+}
+
+void sub(int *x, int *y, int *result) {
+  *result = *x - *y;
+}
+
+int divide(int n, int d, int *r) {
+   int q;
+   q = n/d;
+   *r = n - q*d;
+   return q;
+}
diff --git a/Examples/python/pointer/example.i b/Examples/python/pointer/example.i
new file mode 100644
index 0000000..a8ac794
--- /dev/null
+++ b/Examples/python/pointer/example.i
@@ -0,0 +1,30 @@
+/* File : example.i */
+%module example
+
+%{
+extern void add(int *, int *, int *);
+extern void sub(int *, int *, int *);
+extern int divide(int, int, int *);
+%}
+
+/* This example illustrates a couple of different techniques
+   for manipulating C pointers */
+
+/* First we'll use the pointer library */
+extern void add(int *x, int *y, int *result);
+%include cpointer.i
+%pointer_functions(int, intp);
+
+/* Next we'll use some typemaps */
+
+%include typemaps.i
+extern void sub(int *INPUT, int *INPUT, int *OUTPUT);
+
+/* Next we'll use typemaps and the %apply directive */
+
+%apply int *OUTPUT { int *r };
+extern int divide(int n, int d, int *r);
+
+
+
+
diff --git a/Examples/python/pointer/index.html b/Examples/python/pointer/index.html
new file mode 100644
index 0000000..ceef305
--- /dev/null
+++ b/Examples/python/pointer/index.html
@@ -0,0 +1,171 @@
+<html>
+<head>
+<title>SWIG:Examples:python:pointer</title>
+</head>
+
+<body bgcolor="#ffffff">
+
+<tt>SWIG/Examples/python/pointer/</tt>
+<hr>
+
+<H2>Simple Pointer Handling</H2>
+
+<p>
+This example illustrates a couple of techniques for handling
+simple pointers in SWIG.  The prototypical example is a C function
+that operates on pointers such as this:
+
+<blockquote>
+<pre>
+void add(int *x, int *y, int *r) { 
+    *r = *x + *y;
+}
+</pre>
+</blockquote>
+
+By default, SWIG wraps this function exactly as specified and creates
+an interface that expects pointer objects for arguments.  The only
+problem is how does one go about creating these objects from a script?
+
+<h2>Possible Solutions</h2>
+
+<ul>
+<li>Write some helper functions to explicitly create objects.  For
+example:
+
+<blockquote>
+<pre>
+int *new_int(int ivalue) {
+  int *i = (int *) malloc(sizeof(ivalue));
+  *i = ivalue;
+  return i;
+}
+int get_int(int *i) {
+  return *i;
+}
+
+void delete_int(int *i) {
+  free(i);
+}
+</pre>
+</blockquote>
+
+Now, in a script you would do this:
+
+<blockquote>
+<pre>
+a = new_int(37)
+b = new_int(42)
+c = new_int(0)
+add(a,b,c)
+r = get_int(c);
+print "Result =",r
+delete_int(a)
+delete_int(b)
+delete_int(c)
+</pre>
+</blockquote>
+
+<p>
+<li>Use the SWIG pointer library.  For example, in the interface file 
+you would do this:
+
+<blockquote>
+<pre>
+%include "pointer.i"
+</pre>
+</blockquote?
+
+and in a script you would do this:
+
+<blockquote>
+<pre>
+a = ptrcreate("int",37)
+b = ptrcreate("int",42)
+c = ptrcreate("int")
+add(a,b,c)
+r = ptrvalue(c)
+print "Result =",r
+ptrfree(a)
+ptrfree(b)
+ptrfree(c)
+</pre>
+</blockquote>
+
+The advantage to using the pointer library is that it unifies some of the helper
+functions behind a common set of names.  For example, the same set of functions work
+with int, double, float, and other fundamental types.
+
+<p>
+<li>Use the SWIG typemap library.  This library allows you to completely
+change the way arguments are processed by SWIG.  For example:
+
+<blockquote>
+<pre>
+%include "typemaps.i"
+void add(int *INPUT, int *INPUT, int *OUTPUT);
+</pre>
+</blockquote>
+
+And in a script:
+
+<blockquote>
+<pre>
+r = add(37,42)
+print "Result =",r
+</pre>
+</blockquote>
+Needless to say, this is substantially easier.
+
+<p>
+<li>A final alternative is to use the typemaps library in combination
+with the %apply directive.  This allows you to change the names of parameters
+that behave as input or output parameters. For example:
+
+<blockquote>
+<pre>
+%include "typemaps.i"
+%apply int *INPUT {int *x, int *y};
+%apply int *OUTPUT {int *r};
+
+void add(int *x, int *y, int *r);
+void sub(int *x, int *y, int *r);
+void mul(int *x, int *y, int *r);
+... etc ...
+</pre>
+</blockquote>
+
+</ul>
+
+<h2>Example</h2>
+
+The following example illustrates the use of these features for pointer
+extraction.
+
+<ul>
+<li> <a href="example.c">example.c</a>  (C Source)
+<li> <a href="example.i">example.i</a>  (Swig interface)
+<li> <a href="example.py">example.py</a> (Python Script)
+</ul>
+
+<h2>Notes</h2>
+
+<ul>
+<li>Since pointers are used for so many different things (arrays, output values,
+etc...) the complexity of pointer handling can be as complicated as you want to
+make it.
+
+<p>
+<li>More documentation on the typemaps.i and pointer.i library files can be
+found in the SWIG user manual.  The files also contain documentation.
+
+<p>
+<li>The pointer.i library is designed primarily for convenience.  If you
+are concerned about performance, you probably want to use a different
+approach.
+
+</ul>
+
+<hr>
+</body>
+</html>
diff --git a/Examples/python/pointer/runme.py b/Examples/python/pointer/runme.py
new file mode 100644
index 0000000..e38a306
--- /dev/null
+++ b/Examples/python/pointer/runme.py
@@ -0,0 +1,44 @@
+# file: runme.py
+
+import example;
+
+# First create some objects using the pointer library.
+print "Testing the pointer library";
+a = example.new_intp();
+b = example.new_intp();
+c = example.new_intp();
+example.intp_assign(a,37);
+example.intp_assign(b,42);
+
+print "     a =",a
+print "     b =",b
+print "     c =",c
+
+# Call the add() function with some pointers
+example.add(a,b,c)
+
+# Now get the result
+r = example.intp_value(c)
+print "     37 + 42 =",r
+
+# Clean up the pointers
+example.delete_intp(a)
+example.delete_intp(b)
+example.delete_intp(c)
+
+# Now try the typemap library
+# This should be much easier. Now how it is no longer
+# necessary to manufacture pointers.
+
+print "Trying the typemap library";
+r = example.sub(37,42)
+print "     37 - 42 =",r
+
+# Now try the version with multiple return values
+
+print "Testing multiple return values";
+q,r = example.divide(42,37)
+print "     42/37 = %d remainder %d" % (q,r)
+
+
+