*
* Inline functions for unaligned memory accesses.
*
+ * 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_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 { \
((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 inline u16
+get_unaligned_u16_le(const void *p)
+{
+ u16 v;
+
+ if (UNALIGNED_ACCESS_IS_FAST) {
+ v = le16_to_cpu(load_le16_unaligned(p));
+ } else {
+ const u8 *p8 = p;
+ v = 0;
+ v |= (u16)p8[0] << 0;
+ v |= (u16)p8[1] << 8;
+ }
+ return v;
+}
+
+static inline u32
+get_unaligned_u32_le(const void *p)
+{
+ u32 v;
+
+ if (UNALIGNED_ACCESS_IS_FAST) {
+ v = le32_to_cpu(load_le32_unaligned(p));
+ } else {
+ const u8 *p8 = p;
+ v = 0;
+ v |= (u32)p8[0] << 0;
+ v |= (u32)p8[1] << 8;
+ v |= (u32)p8[2] << 16;
+ v |= (u32)p8[3] << 24;
+ }
+ return v;
+}
+
+static inline void
+put_unaligned_u16_le(u16 v, void *p)
+{
+ if (UNALIGNED_ACCESS_IS_FAST) {
+ store_le16_unaligned(cpu_to_le16(v), p);
+ } else {
+ u8 *p8 = p;
+ p8[0] = (v >> 0) & 0xFF;
+ p8[1] = (v >> 8) & 0xFF;
+ }
+}
+
+static inline void
+put_unaligned_u32_le(u32 v, void *p)
+{
+ if (UNALIGNED_ACCESS_IS_FAST) {
+ store_le32_unaligned(cpu_to_le32(v), p);
+ } else {
+ u8 *p8 = p;
+ p8[0] = (v >> 0) & 0xFF;
+ p8[1] = (v >> 8) & 0xFF;
+ p8[2] = (v >> 16) & 0xFF;
+ p8[3] = (v >> 24) & 0xFF;
+ }
+}
+
+/*
+ * 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 inline 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 inline 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
+ return ((u32)p[0] << 0) | ((u32)p[1] << 8) | ((u32)p[2] << 16);
+#endif
+}
+
#endif /* _WIMLIB_UNALIGNED_H */