/*
- * unaligned.h
+ * unaligned.h - inline functions for unaligned memory accesses
*
- * Inline functions for unaligned memory accesses.
+ * The following copying information applies to this specific source code file:
*
- * The author dedicates this file to the public domain.
- * You can do whatever you want with this file.
+ * Written in 2014-2015 by Eric Biggers <ebiggers3@gmail.com>
+ *
+ * To the extent possible under law, the author(s) have dedicated all copyright
+ * and related and neighboring rights to this software to the public domain
+ * worldwide via the Creative Commons Zero 1.0 Universal Public Domain
+ * Dedication (the "CC0").
+ *
+ * This software is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the CC0 for more details.
+ *
+ * You should have received a copy of the CC0 along with this software; if not
+ * see <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#ifndef _WIMLIB_UNALIGNED_H
#define _WIMLIB_UNALIGNED_H
-#include "compiler.h"
-#include "endianness.h"
-#include "types.h"
+#include "wimlib/compiler.h"
+#include "wimlib/endianness.h"
+#include "wimlib/types.h"
#define DEFINE_UNALIGNED_TYPE(type) \
struct type##_unaligned { \
type v; \
} _packed_attribute; \
\
-static inline type \
+static forceinline type \
load_##type##_unaligned(const void *p) \
{ \
return ((const struct type##_unaligned *)p)->v; \
} \
\
-static inline void \
+static forceinline void \
store_##type##_unaligned(type val, void *p) \
{ \
((struct type##_unaligned *)p)->v = val; \
}
+DEFINE_UNALIGNED_TYPE(u16);
+DEFINE_UNALIGNED_TYPE(u32);
+DEFINE_UNALIGNED_TYPE(u64);
DEFINE_UNALIGNED_TYPE(le16);
DEFINE_UNALIGNED_TYPE(le32);
DEFINE_UNALIGNED_TYPE(le64);
+DEFINE_UNALIGNED_TYPE(be16);
DEFINE_UNALIGNED_TYPE(be32);
+DEFINE_UNALIGNED_TYPE(be64);
DEFINE_UNALIGNED_TYPE(size_t);
+DEFINE_UNALIGNED_TYPE(machine_word_t);
+
+#define load_word_unaligned load_machine_word_t_unaligned
+#define store_word_unaligned store_machine_word_t_unaligned
+
+static forceinline u16
+get_unaligned_le16(const u8 *p)
+{
+ if (UNALIGNED_ACCESS_IS_FAST)
+ return le16_to_cpu(load_le16_unaligned(p));
+ else
+ return ((u16)p[1] << 8) | p[0];
+}
+
+static forceinline u32
+get_unaligned_le32(const u8 *p)
+{
+ if (UNALIGNED_ACCESS_IS_FAST)
+ return le32_to_cpu(load_le32_unaligned(p));
+ else
+ return ((u32)p[3] << 24) | ((u32)p[2] << 16) |
+ ((u32)p[1] << 8) | p[0];
+}
+
+static forceinline void
+put_unaligned_le16(u16 v, u8 *p)
+{
+ if (UNALIGNED_ACCESS_IS_FAST) {
+ store_le16_unaligned(cpu_to_le16(v), p);
+ } else {
+ p[0] = (u8)(v >> 0);
+ p[1] = (u8)(v >> 8);
+ }
+}
+
+static forceinline void
+put_unaligned_le32(u32 v, u8 *p)
+{
+ if (UNALIGNED_ACCESS_IS_FAST) {
+ store_le32_unaligned(cpu_to_le32(v), p);
+ } else {
+ p[0] = (u8)(v >> 0);
+ p[1] = (u8)(v >> 8);
+ p[2] = (u8)(v >> 16);
+ p[3] = (u8)(v >> 24);
+ }
+}
+
+/*
+ * Given a 32-bit value that was loaded with the platform's native endianness,
+ * return a 32-bit value whose high-order 8 bits are 0 and whose low-order 24
+ * bits contain the first 3 bytes, arranged in octets in a platform-dependent
+ * order, at the memory location from which the input 32-bit value was loaded.
+ */
+static forceinline u32
+loaded_u32_to_u24(u32 v)
+{
+ if (CPU_IS_LITTLE_ENDIAN)
+ return v & 0xFFFFFF;
+ else
+ return v >> 8;
+}
+
+/*
+ * Load the next 3 bytes from the memory location @p into the 24 low-order bits
+ * of a 32-bit value. The order in which the 3 bytes will be arranged as octets
+ * in the 24 bits is platform-dependent. At least LOAD_U24_REQUIRED_NBYTES
+ * bytes must be available at @p; note that this may be more than 3.
+ */
+static forceinline u32
+load_u24_unaligned(const u8 *p)
+{
+#if UNALIGNED_ACCESS_IS_FAST
+# define LOAD_U24_REQUIRED_NBYTES 4
+ return loaded_u32_to_u24(load_u32_unaligned(p));
+#else
+# define LOAD_U24_REQUIRED_NBYTES 3
+# if CPU_IS_BIG_ENDIAN
+ return ((u32)p[2] << 0) | ((u32)p[1] << 8) | ((u32)p[0] << 16);
+# else
+ return ((u32)p[0] << 0) | ((u32)p[1] << 8) | ((u32)p[2] << 16);
+# endif
+#endif
+}
+
#endif /* _WIMLIB_UNALIGNED_H */
git://wimlib.net / wimlib / blobdiff