Use C++ function templating for skip()/construct()

Author: jnothman

msgpack/_msgpack.pyx

@@ -208,8 +208,10 @@ cdef extern from "unpack.h":
         unsigned int ct
         PyObject* key
 
-    int template_execute(template_context* ctx, const_char_ptr data,
-                         size_t len, size_t* off, bint construct) except -1
+    ctypedef int (*execute_fn)(template_context* ctx, const_char_ptr data,
+                               size_t len, size_t* off) except -1
+    execute_fn template_construct
+    execute_fn template_skip
     void template_init(template_context* ctx)
     object template_data(template_context* ctx)
 
@@ -257,7 +259,7 @@ def unpackb(object packed, object object_hook=None, object list_hook=None,
         if not PyCallable_Check(list_hook):
             raise TypeError("list_hook must be a callable.")
         ctx.user.list_hook = <PyObject*>list_hook
-    ret = template_execute(&ctx, buf, buf_len, &off, 1)
+    ret = template_construct(&ctx, buf, buf_len, &off)
     if ret == 1:
         obj = template_data(&ctx)
         if off < buf_len:
@@ -455,16 +457,13 @@ cdef class Unpacker(object):
         else:
             self.file_like = None
 
-    cdef object _unpack(self, bint construct):
+    cdef object _unpack(self, execute_fn execute):
         cdef int ret
         cdef object obj
         while 1:
-            ret = template_execute(&self.ctx, self.buf, self.buf_tail, &self.buf_head, construct)
+            ret = execute(&self.ctx, self.buf, self.buf_tail, &self.buf_head)
             if ret == 1:
-                if construct:
-                    obj = template_data(&self.ctx)
-                else:
-                    obj = None
+                obj = template_data(&self.ctx)
                 template_init(&self.ctx)
                 return obj
             elif ret == 0:
@@ -477,17 +476,17 @@ cdef class Unpacker(object):
 
     def unpack(self):
         """unpack one object"""
-        return self._unpack(1)
+        return self._unpack(template_construct)
 
     def skip(self):
         """read and ignore one object, returning None"""
-        return self._unpack(0)
+        return self._unpack(template_skip)
 
     def __iter__(self):
         return self
 
     def __next__(self):
-        return self._unpack(1)
+        return self._unpack(template_construct)
 
     # for debug.
     #def _buf(self):

msgpack/unpack.h

@@ -41,6 +41,7 @@ typedef struct unpack_user {
 
 #define msgpack_unpack_user unpack_user
 
+typedef int (*execute_fn)(msgpack_unpack_struct(_context)* ctx, const char* data, size_t len, size_t* off);
 
 struct template_context;
 typedef struct template_context template_context;

msgpack/unpack_template.h

@@ -95,7 +95,8 @@ msgpack_unpack_func(msgpack_unpack_object, _data)(msgpack_unpack_struct(_context
 }
 
 
-msgpack_unpack_func(int, _execute)(msgpack_unpack_struct(_context)* ctx, const char* data, size_t len, size_t* off, int construct)
+template <bool construct>
+msgpack_unpack_func(int, _execute)(msgpack_unpack_struct(_context)* ctx, const char* data, size_t len, size_t* off)
 {
 	assert(len >= *off);
 
@@ -380,6 +381,8 @@ msgpack_unpack_func(int, _execute)(msgpack_unpack_struct(_context)* ctx, const c
 
 
 _finish:
+	if (!construct)
+		msgpack_unpack_callback(_nil)(user, &obj);
 	stack[0].obj = obj;
 	++p;
 	ret = 1;
@@ -405,20 +408,22 @@ msgpack_unpack_func(int, _execute)(msgpack_unpack_struct(_context)* ctx, const c
 #undef construct_cb
 }
 
-
-#undef msgpack_unpack_func
-#undef msgpack_unpack_callback
-#undef msgpack_unpack_struct
-#undef msgpack_unpack_object
-#undef msgpack_unpack_user
-
 #undef push_simple_value
 #undef push_fixed_value
 #undef push_variable_value
 #undef again_fixed_trail
 #undef again_fixed_trail_if_zero
 #undef start_container
 
+static const execute_fn template_construct = &template_execute<true>;
+static const execute_fn template_skip = &template_execute<false>;
+
+#undef msgpack_unpack_func
+#undef msgpack_unpack_callback
+#undef msgpack_unpack_struct
+#undef msgpack_unpack_object
+#undef msgpack_unpack_user
+
 #undef NEXT_CS
 
 /* vim: set ts=4 sw=4 noexpandtab  */

setup.py

@@ -18,7 +18,7 @@
 
 def cythonize(src):
     sys.stderr.write("cythonize: %r\n" % (src,))
-    cython_compiler.compile([src])
+    cython_compiler.compile([src], cplus=True)
 
 def ensure_source(src):
     pyx = os.path.splitext(src)[0] + '.pyx'
@@ -67,7 +67,7 @@ def __init__(self, *args, **kwargs):
 else:
     Sdist = sdist
 
-sources = ['msgpack/_msgpack.c']
+sources = ['msgpack/_msgpack.cpp']
 libraries = []
 if sys.platform == 'win32':
     libraries.append('ws2_32')