array module support: byteswap()

pythran/pythonic/array/array/byteswap.hpp

@@ -0,0 +1,46 @@
+#ifndef PYTHONIC_ARRAY_ARRAY_BYTESWAP_HPP
+#define PYTHONIC_ARRAY_ARRAY_BYTESWAP_HPP
+
+#include "pythonic/include/array/array/byteswap.hpp"
+#include "pythonic/utils/functor.hpp"
+
+#include <byteswap.h>
+
+PYTHONIC_NS_BEGIN
+
+namespace array
+{
+
+  namespace array
+  {
+    void byteswap(char *buffer, size_t n, std::integral_constant<unsigned, 2>)
+    {
+      auto *ibuffer = reinterpret_cast<uint16_t *>(buffer);
+      for (size_t i = 0; i < n; i++)
+        ibuffer[i] = bswap_16(ibuffer[i]);
+    }
+    void byteswap(char *buffer, size_t n, std::integral_constant<unsigned, 4>)
+    {
+      auto *ibuffer = reinterpret_cast<uint32_t *>(buffer);
+      for (size_t i = 0; i < n; i++)
+        ibuffer[i] = bswap_32(ibuffer[i]);
+    }
+    void byteswap(char *buffer, size_t n, std::integral_constant<unsigned, 8>)
+    {
+      auto *ibuffer = reinterpret_cast<uint64_t *>(buffer);
+      for (size_t i = 0; i < n; i++)
+        ibuffer[i] = bswap_64(ibuffer[i]);
+    }
+
+    template <class T>
+    types::none_type byteswap(types::array<T> &seq)
+    {
+      byteswap(reinterpret_cast<char *>(seq.data()), seq.size(),
+               std::integral_constant<unsigned, sizeof(T)>{});
+      return {};
+    }
+
+  } // namespace array
+} // namespace array
+PYTHONIC_NS_END
+#endif

pythran/pythonic/include/array/array/byteswap.hpp

@@ -0,0 +1,28 @@
+#ifndef PYTHONIC_INCLUDE_ARRAY_ARRAY_BYTESWAP_HPP
+#define PYTHONIC_INCLUDE_ARRAY_ARRAY_BYTESWAP_HPP
+
+#include "pythonic/include/types/array.hpp"
+#include "pythonic/include/utils/functor.hpp"
+
+PYTHONIC_NS_BEGIN
+
+namespace array
+{
+
+  namespace array
+  {
+
+    template <class T>
+    types::none_type byteswap(types::array<T> &seq);
+
+    template <class T>
+    types::none_type byteswap(types::array<T> &&seq)
+    {
+      return {};
+    }
+
+    DEFINE_FUNCTOR(pythonic::array::array, byteswap);
+  } // namespace array
+} // namespace array
+PYTHONIC_NS_END
+#endif

pythran/tables.py

@@ -182,7 +182,8 @@ def update_effects(self, node):
     "array": {
         # array have fixed type, no need for signature
         "append": MethodIntr(),
-        "buffer_info": MethodIntr(),
+        "buffer_info": ConstMethodIntr(),
+        "byteswap": MethodIntr(),
     },
     "list": {
         "append": MethodIntr(signature=Fun[[List[T0], T0], None]),

pythran/tests/test_array.py

@@ -33,3 +33,7 @@ def test_array_append(self):
     def test_array_buffer_info(self):
         self.run_test("def array_buffer_info_(n): import array; x = array.array('h', [n]); return x.buffer_info()[1]",
                       2, array_buffer_info_=[int])
+
+    def test_array_byteswap(self):
+        self.run_test("def array_byteswap_(n): import array; x = array.array('H', [n]); x.byteswap(); return x.tolist()",
+                      2, array_byteswap_=[int])