mesa: Add _mesa_swap2_copy and _mesa_swap4_copy

We have _mesa_swap{2,4} but these do in-place byte-swapping only. The new
functions receive an extra parameter so we can swap bytes on a source
input array and store the results in a (possibly different) destination
array.

This is useful to implement byte-swapping in pixel uploads, since in this
case we need to swap bytes on the src data which is owned by the
application so we can't do an in-place byte swap.

v2:
  - Include compiler.h in image.h, which is necessary to build in MSCV as
    indicated by Brian Paul.

Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/src/mesa/main/image.h b/src/mesa/main/image.h
index abd84bf..44863cc 100644
--- a/src/mesa/main/image.h
+++ b/src/mesa/main/image.h
@@ -28,15 +28,28 @@
 
 
 #include "glheader.h"
+#include "compiler.h"
 
 struct gl_context;
 struct gl_pixelstore_attrib;
 
 extern void
-_mesa_swap2( GLushort *p, GLuint n );
+_mesa_swap2_copy(GLushort *dst, GLushort *src, GLuint n);
 
 extern void
-_mesa_swap4( GLuint *p, GLuint n );
+_mesa_swap4_copy(GLuint *dst, GLuint *src, GLuint n);
+
+static inline void
+_mesa_swap2(GLushort *p, GLuint n)
+{
+   _mesa_swap2_copy(p, p, n);
+}
+
+static inline void
+_mesa_swap4(GLuint *p, GLuint n)
+{
+   _mesa_swap4_copy(p, p, n);
+}
 
 extern GLintptr
 _mesa_image_offset( GLuint dimensions,