Two demos of how CFFI can be used to write your own C functions

using whatever API is most suitable.

1 files changed, 58 insertions, 0 deletions

diff --git a/demo/pyobj.py b/demo/pyobj.py
new file mode 100644
index 0000000..c945f5a
--- /dev/null
+++ b/demo/pyobj.py
@@ -0,0 +1,58 @@
+import api
+
+ffi = api.PythonFFI()
+
+referents = []
+freelist = None
+
+def store(x):
+    global freelist
+    if freelist is None:
+        i = len(referents)
+        referents.append(x)
+    else:
+        i = freelist = referents[freelist]
+        referents[i] = x
+    return i
+
+def discard(i):
+    global freelist
+    referents[i] = freelist
+    freelist = i
+
+class Ref(object):
+    def __init__(self, x):
+        self.x = x
+    def __enter__(self):
+        self.i = i = store(self.x)
+        return i
+    def __exit__(self, *args):
+        discard(self.i)
+
+# ------------------------------------------------------------
+
+ffi.cdef("""
+    typedef int pyobj_t;
+    int sum(pyobj_t oblist, int count);
+""")
+
+@ffi.pyexport("int(pyobj_t, int)")
+def getitem(oblist, index):
+    list = referents[oblist]
+    return list[index]
+
+lib = ffi.verify("""
+    typedef int pyobj_t;
+
+    int sum(pyobj_t oblist, int count) {
+        int i, result = 0;
+        for (i=0; i<count; i++) {
+            int n = getitem(oblist, i);
+            result += n;
+        }
+        return result;
+    }
+""")
+
+with Ref([10, 20, 30, 40]) as oblist:
+    print lib.sum(oblist, 4)