Make code endianness-agnostic

configure.ac

@@ -47,6 +47,7 @@ case "$host_os" in
     AC_DEFINE([_DEFAULT_SOURCE], [], [Enable vsyslog().])
 	;;
 esac
+AC_C_BIGENDIAN(,, [AC_MSG_ERROR([Unknown endianness])])
 AC_CONFIG_HEADERS([libexfat/config.h])
 AC_CONFIG_FILES([
 	libexfat/Makefile

libexfat/byteorder.h

@@ -23,46 +23,59 @@
 #ifndef BYTEORDER_H_INCLUDED
 #define BYTEORDER_H_INCLUDED
 
-#include "platform.h"
+#include "config.h"
 #include <stdint.h>
 #include <stddef.h>
 
+#ifdef WORDS_BIGENDIAN
+typedef unsigned char bitmap_t;
+#else
+typedef size_t bitmap_t;
+#endif
+
 typedef struct { uint16_t __u16; } le16_t;
 typedef struct { uint32_t __u32; } le32_t;
 typedef struct { uint64_t __u64; } le64_t;
 
-#if EXFAT_BYTE_ORDER == EXFAT_LITTLE_ENDIAN
-
-static inline uint16_t le16_to_cpu(le16_t v) { return v.__u16; }
-static inline uint32_t le32_to_cpu(le32_t v) { return v.__u32; }
-static inline uint64_t le64_to_cpu(le64_t v) { return v.__u64; }
-
-static inline le16_t cpu_to_le16(uint16_t v) { le16_t t = {v}; return t; }
-static inline le32_t cpu_to_le32(uint32_t v) { le32_t t = {v}; return t; }
-static inline le64_t cpu_to_le64(uint64_t v) { le64_t t = {v}; return t; }
-
-typedef size_t bitmap_t;
-
-#elif EXFAT_BYTE_ORDER == EXFAT_BIG_ENDIAN
-
-static inline uint16_t le16_to_cpu(le16_t v)
-	{ return exfat_bswap16(v.__u16); }
-static inline uint32_t le32_to_cpu(le32_t v)
-	{ return exfat_bswap32(v.__u32); }
-static inline uint64_t le64_to_cpu(le64_t v)
-	{ return exfat_bswap64(v.__u64); }
-
-static inline le16_t cpu_to_le16(uint16_t v)
-	{ le16_t t = {exfat_bswap16(v)}; return t; }
-static inline le32_t cpu_to_le32(uint32_t v)
-	{ le32_t t = {exfat_bswap32(v)}; return t; }
-static inline le64_t cpu_to_le64(uint64_t v)
-	{ le64_t t = {exfat_bswap64(v)}; return t; }
-
-typedef unsigned char bitmap_t;
-
-#else
-#error Wow! You have a PDP machine?!
-#endif
+static inline uint16_t le16_to_cpu(le16_t v) {
+	unsigned char *p = (unsigned char *)&v;
+	return p[0] | p[1] << 8;
+}
+
+static inline uint32_t le32_to_cpu(le32_t v) {
+	unsigned char *p = (unsigned char *)&v;
+	return p[0] | p[1] << 8 | p[2] << 16 | (uint32_t)p[3] << 24;
+}
+static inline uint64_t le64_to_cpu(le64_t v) {
+	unsigned char *p = (unsigned char *)&v;
+	uint64_t rval = 0;
+
+	rval |= (uint64_t)p[0]       | (uint64_t)p[1] <<  8;
+	rval |= (uint64_t)p[2] << 16 | (uint64_t)p[3] << 24;
+	rval |= (uint64_t)p[4] << 32 | (uint64_t)p[5] << 40;
+	rval |= (uint64_t)p[6] << 48 | (uint64_t)p[7] << 56;
+	return rval;
+}
+
+static inline le16_t cpu_to_le16(uint16_t v) {
+	le16_t t;
+	unsigned char *p = (unsigned char *)&t;
+	p[0] = v      ; p[1] = v >>  8;
+	return t;
+}
+static inline le32_t cpu_to_le32(uint32_t v) {
+	le32_t t;
+	unsigned char *p = (unsigned char *)&t;
+	p[0] = v      ; p[1] = v >>= 8; p[2] = v >>= 8; p[3] = v >>  8;
+	return t;
+}
+
+static inline le64_t cpu_to_le64(uint64_t v) {
+	le64_t t;
+	unsigned char *p = (unsigned char *)&t;
+	p[0] = v      ; p[1] = v >>= 8; p[2] = v >>= 8; p[3] = v >>= 8;
+	p[4] = v >>= 8; p[5] = v >>= 8; p[6] = v >>= 8; p[7] = v >>  8;
+	return t;
+}
 
 #endif /* ifndef BYTEORDER_H_INCLUDED */