In order to prepare for LZ77 matchfinder. Note that erofs_memcmp2() is still not quite effective.
Signed-off-by: Gao Xiang <[email protected]> --- include/erofs/defs.h | 24 ++++++++++++++++++++++-- include/erofs/internal.h | 2 -- lib/dedupe.c | 23 ++++++++++++++++++----- 3 files changed, 40 insertions(+), 9 deletions(-) diff --git a/include/erofs/defs.h b/include/erofs/defs.h index e5aa23c..44af557 100644 --- a/include/erofs/defs.h +++ b/include/erofs/defs.h @@ -179,9 +179,29 @@ typedef int64_t s64; #define __maybe_unused __attribute__((__unused__)) #endif -static inline u32 get_unaligned_le32(const u8 *p) +#define __packed __attribute__((__packed__)) + +#define __get_unaligned_t(type, ptr) ({ \ + const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \ + __pptr->x; \ +}) + +#define __put_unaligned_t(type, val, ptr) do { \ + struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \ + __pptr->x = (val); \ +} while (0) + +#define get_unaligned(ptr) __get_unaligned_t(typeof(*(ptr)), (ptr)) +#define put_unaligned(val, ptr) __put_unaligned_t(typeof(*(ptr)), (val), (ptr)) + +static inline u32 get_unaligned_le32(const void *p) +{ + return le32_to_cpu(__get_unaligned_t(__le32, p)); +} + +static inline void put_unaligned_le32(u32 val, void *p) { - return p[0] | p[1] << 8 | p[2] << 16 | p[3] << 24; + __put_unaligned_t(__le32, cpu_to_le32(val), p); } /** diff --git a/include/erofs/internal.h b/include/erofs/internal.h index ab964d4..aad2115 100644 --- a/include/erofs/internal.h +++ b/include/erofs/internal.h @@ -17,8 +17,6 @@ extern "C" typedef unsigned short umode_t; -#define __packed __attribute__((__packed__)) - #include "erofs_fs.h" #include <fcntl.h> #include <sys/types.h> /* for off_t definition */ diff --git a/lib/dedupe.c b/lib/dedupe.c index 0a69b8f..17da452 100644 --- a/lib/dedupe.c +++ b/lib/dedupe.c @@ -11,12 +11,14 @@ unsigned long erofs_memcmp2(const u8 *s1, const u8 *s2, unsigned long sz) { + const unsigned long *a1, *a2; unsigned long n = sz; - if (sz >= sizeof(long) && ((long)s1 & (sizeof(long) - 1)) == - ((long)s2 & (sizeof(long) - 1))) { - const unsigned long *a1, *a2; + if (sz < sizeof(long)) + goto out_bytes; + if (((long)s1 & (sizeof(long) - 1)) == + ((long)s2 & (sizeof(long) - 1))) { while ((long)s1 & (sizeof(long) - 1)) { if (*s1 != *s2) break; @@ -34,9 +36,20 @@ unsigned long erofs_memcmp2(const u8 *s1, const u8 *s2, ++a2; sz -= sizeof(long); } - s1 = (const u8 *)a1; - s2 = (const u8 *)a2; + } else { + a1 = (const unsigned long *)s1; + a2 = (const unsigned long *)s2; + do { + if (get_unaligned(a1) != get_unaligned(a2)) + break; + ++a1; + ++a2; + sz -= sizeof(long); + } while (sz >= sizeof(long)); } + s1 = (const u8 *)a1; + s2 = (const u8 *)a2; +out_bytes: while (sz) { if (*s1 != *s2) break; -- 2.24.4
