X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=include%2Fwimlib%2Fendianness.h;h=772724dfd6b88b54362ae079f60828db780a131a;hp=4c1b239fc780a65646bad3dea43ba9938520432c;hb=6cf66357e5b64c1b7460b42d45740dd8eaeca36e;hpb=f2d4403b993204bffba09dca31b424d158218209

diff --git a/include/wimlib/endianness.h b/include/wimlib/endianness.h
index 4c1b239f..772724df 100644
--- a/include/wimlib/endianness.h
+++ b/include/wimlib/endianness.h
@@ -1,71 +1,102 @@
+/*
+ * endianness.h
+ *
+ * Macros and inline functions for endianness conversion.
+ *
+ * Author:	Eric Biggers
+ * Year:	2014, 2015
+ *
+ * The author dedicates this file to the public domain.
+ * You can do whatever you want with this file.
+ */
+
 #ifndef _WIMLIB_ENDIANNESS_H
 #define _WIMLIB_ENDIANNESS_H
 
+#include "wimlib/compiler.h"
 #include "wimlib/types.h"
 
-/* Watch out for conflict with ntfs-3g/endian.h ... */
-
+/* Watch out for conflict with ntfs-3g/endians.h ... */
 #ifndef _NTFS_ENDIANS_H
 
-static inline u16
-bswap16(u16 n)
+#define bswap16_const(n)			\
+	((((u16)(n) & 0x00FF) << 8)	|	\
+	 (((u16)(n) & 0xFF00) >> 8))
+
+#define bswap32_const(n)				\
+	((((u32)(n) & 0x000000FF) << 24)	|	\
+	 (((u32)(n) & 0x0000FF00) << 8)		|	\
+	 (((u32)(n) & 0x00FF0000) >> 8)		|	\
+	 (((u32)(n) & 0xFF000000) >> 24))
+
+#define bswap64_const(n)					\
+	((((u64)(n) & 0x00000000000000FF) << 56)	|	\
+	 (((u64)(n) & 0x000000000000FF00) << 40)	|	\
+	 (((u64)(n) & 0x0000000000FF0000) << 24)	|	\
+	 (((u64)(n) & 0x00000000FF000000) << 8)		|	\
+	 (((u64)(n) & 0x000000FF00000000) >> 8)		|	\
+	 (((u64)(n) & 0x0000FF0000000000) >> 24)	|	\
+	 (((u64)(n) & 0x00FF000000000000) >> 40)	|	\
+	 (((u64)(n) & 0xFF00000000000000) >> 56))
+
+static inline u16 do_bswap16(u16 n)
 {
-	return (n << 8) | (n >> 8);
+#ifdef compiler_bswap16
+	return compiler_bswap16(n);
+#else
+	return bswap16_const(n);
+#endif
 }
 
-static inline u32
-bswap32(u32 n)
+static inline u32 do_bswap32(u32 n)
 {
-#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
-	return __builtin_bswap32(n);
+#ifdef compiler_bswap32
+	return compiler_bswap32(n);
 #else
-	return (n << 24) | ((n & 0xff00) << 8) | ((n & 0xff0000) >> 8) |
-							(n >> 24);
+	return bswap32_const(n);
 #endif
 }
 
-static inline u64
-bswap64(u64 n)
+static inline u64 do_bswap64(u64 n)
 {
-#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
-	return __builtin_bswap64(n);
+#ifdef compiler_bswap64
+	return compiler_bswap64(n);
 #else
-	return (n << 56) | ((n & 0xff00) << 40) | ((n & 0xff0000) << 24) |
-			((n & 0xff000000) << 8) | ((n & 0xff00000000) >> 8) |
-			((n & 0xff0000000000) >> 24) |
-			((n & 0xff000000000000) >> 40) | (n >> 56);
+	return bswap64_const(n);
 #endif
 }
 
-#  ifdef WORDS_BIGENDIAN
-#    define cpu_to_le16(n) ((_force_attr le16)bswap16(n))
-#    define cpu_to_le32(n) ((_force_attr le32)bswap32(n))
-#    define cpu_to_le64(n) ((_force_attr le64)bswap64(n))
-#    define le16_to_cpu(n) bswap16((_force_attr u16)(le16)(n))
-#    define le32_to_cpu(n) bswap32((_force_attr u32)(le32)(n))
-#    define le64_to_cpu(n) bswap64((_force_attr u64)(le64)(n))
+#define bswap16(n) (__builtin_constant_p(n) ? bswap16_const(n) : do_bswap16(n))
+#define bswap32(n) (__builtin_constant_p(n) ? bswap32_const(n) : do_bswap32(n))
+#define bswap64(n) (__builtin_constant_p(n) ? bswap64_const(n) : do_bswap64(n))
 
-#    define cpu_to_be16(n) ((_force_attr be16)(u16)(n))
-#    define cpu_to_be32(n) ((_force_attr be32)(u32)(n))
-#    define cpu_to_be64(n) ((_force_attr be64)(u64)(n))
-#    define be16_to_cpu(n) ((_force_attr u16)(be16)(n))
-#    define be32_to_cpu(n) ((_force_attr u32)(be32)(n))
-#    define be64_to_cpu(n) ((_force_attr u64)(be64)(n))
-#  else
-#    define cpu_to_le16(n) ((_force_attr le16)(u16)(n))
-#    define cpu_to_le32(n) ((_force_attr le32)(u32)(n))
-#    define cpu_to_le64(n) ((_force_attr le64)(u64)(n))
-#    define le16_to_cpu(n) ((_force_attr u16)(le16)(n))
-#    define le32_to_cpu(n) ((_force_attr u32)(le32)(n))
-#    define le64_to_cpu(n) ((_force_attr u64)(le64)(n))
+#if CPU_IS_BIG_ENDIAN
+#  define cpu_to_le16(n) ((_force_attr le16)bswap16(n))
+#  define cpu_to_le32(n) ((_force_attr le32)bswap32(n))
+#  define cpu_to_le64(n) ((_force_attr le64)bswap64(n))
+#  define le16_to_cpu(n) bswap16((_force_attr u16)(le16)(n))
+#  define le32_to_cpu(n) bswap32((_force_attr u32)(le32)(n))
+#  define le64_to_cpu(n) bswap64((_force_attr u64)(le64)(n))
+#  define cpu_to_be16(n) ((_force_attr be16)(u16)(n))
+#  define cpu_to_be32(n) ((_force_attr be32)(u32)(n))
+#  define cpu_to_be64(n) ((_force_attr be64)(u64)(n))
+#  define be16_to_cpu(n) ((_force_attr u16)(be16)(n))
+#  define be32_to_cpu(n) ((_force_attr u32)(be32)(n))
+#  define be64_to_cpu(n) ((_force_attr u64)(be64)(n))
+#else
+#  define cpu_to_le16(n) ((_force_attr le16)(u16)(n))
+#  define cpu_to_le32(n) ((_force_attr le32)(u32)(n))
+#  define cpu_to_le64(n) ((_force_attr le64)(u64)(n))
+#  define le16_to_cpu(n) ((_force_attr u16)(le16)(n))
+#  define le32_to_cpu(n) ((_force_attr u32)(le32)(n))
+#  define le64_to_cpu(n) ((_force_attr u64)(le64)(n))
+#  define cpu_to_be16(n) ((_force_attr be16)bswap16(n))
+#  define cpu_to_be32(n) ((_force_attr be32)bswap32(n))
+#  define cpu_to_be64(n) ((_force_attr be64)bswap64(n))
+#  define be16_to_cpu(n) bswap16((_force_attr u16)(be16)(n))
+#  define be32_to_cpu(n) bswap32((_force_attr u32)(be32)(n))
+#  define be64_to_cpu(n) bswap64((_force_attr u64)(be64)(n))
+#endif
 
-#    define cpu_to_be16(n) ((_force_attr be16)bswap16(n))
-#    define cpu_to_be32(n) ((_force_attr be32)bswap32(n))
-#    define cpu_to_be64(n) ((_force_attr be64)bswap64(n))
-#    define be16_to_cpu(n) bswap16((_force_attr u16)(be16)(n))
-#    define be32_to_cpu(n) bswap32((_force_attr u32)(be32)(n))
-#    define be64_to_cpu(n) bswap64((_force_attr u64)(be64)(n))
-#  endif
 #endif /* _NTFS_ENDIANS_H */
-
 #endif /* _WIMLIB_ENDIANNESS_H */