[Spice-devel] [PATCH v2 1/2] Detects processor endianess using preprocessor

[Frediano Ziglio]

This allow to define macros based on endianess in public headers

Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
---
 spice/macros.h | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/spice/macros.h b/spice/macros.h
index 62157b4..3538989 100644
--- a/spice/macros.h
+++ b/spice/macros.h
@@ -359,4 +359,59 @@
 #endif /* generic */
 
 
+/* detect endianess */
+#undef SPICE_ENDIAN
+#define SPICE_ENDIAN_LITTLE 4321
+#define SPICE_ENDIAN_BIG    1234
+#define SPICE_ENDIAN_PDP    2143
+
+/* gcc already defined these, use them */
+#if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) \
+    && defined(__ORDER_BIG_ENDIAN__) && defined(__ORDER_PDP_ENDIAN__)
+#  if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#    define SPICE_ENDIAN SPICE_ENDIAN_LITTLE
+#  elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#    define SPICE_ENDIAN SPICE_ENDIAN_BIG
+#  elif __BYTE_ORDER__ == __ORDER_PDP_ENDIAN__
+#    define SPICE_ENDIAN SPICE_ENDIAN_PDP
+#  else
+#    error __BYTE_ORDER__ not defined correctly
+#  endif
+#endif
+
+/* use suggestions at http://sourceforge.net/p/predef/wiki/Endianness/ */
+#ifndef SPICE_ENDIAN
+#  if defined(__LITTLE_ENDIAN__) || defined(__ARMEL__) \
+      || defined(__THUMBEL__) || defined(__AARCH64EL__) \
+      || defined(_MIPSEL) || defined(__MIPSEL) || defined(__MIPSEL__)
+#    define SPICE_ENDIAN SPICE_ENDIAN_LITTLE
+#  endif
+#  if defined(__BIG_ENDIAN__) || defined(__ARMEB__) \
+      || defined(__THUMBEB__) || defined(__AARCH64EB__) \
+      || defined(_MIPSEB) || defined(__MIPSEB) || defined(__MIPSEB__)
+#    ifdef SPICE_ENDIAN
+#      error Both little and big endian detected
+#    endif
+#    define SPICE_ENDIAN SPICE_ENDIAN_BIG
+#  endif
+#endif
+
+/* MS compiler */
+#if !defined(SPICE_ENDIAN) && defined(_MSC_VER)
+/* Windows support only little endian arm */
+#  if defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) \
+      || defined(_M_ARM)
+#    define SPICE_ENDIAN SPICE_ENDIAN_LITTLE
+#  endif
+#endif
+
+#if !defined(SPICE_ENDIAN)
+#error Unable to detect processor endianess
+#endif
+
+#if SPICE_ENDIAN == SPICE_ENDIAN_PDP
+#error PDP endianess not supported by Spice
+#endif
+
+
 #endif /* _H_SPICE_MACROS */
-- 
2.1.0