diff options
| -rw-r--r-- | xdiff/xutils.c | 30 |
1 files changed, 15 insertions, 15 deletions
diff --git a/xdiff/xutils.c b/xdiff/xutils.c index ae6ce0d..9504eae 100644 --- a/xdiff/xutils.c +++ b/xdiff/xutils.c @@ -251,9 +251,11 @@ static unsigned long xdl_hash_record_with_whitespace(char const **data, #ifdef XDL_FAST_HASH -#define ONEBYTES 0x0101010101010101ul -#define NEWLINEBYTES 0x0a0a0a0a0a0a0a0aul -#define HIGHBITS 0x8080808080808080ul +#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x)) + +#define ONEBYTES REPEAT_BYTE(0x01) +#define NEWLINEBYTES REPEAT_BYTE(0x0a) +#define HIGHBITS REPEAT_BYTE(0x80) /* Return the high bit set in the first byte that is a zero */ static inline unsigned long has_zero(unsigned long a) @@ -270,21 +272,19 @@ static inline long count_masked_bytes(unsigned long mask) * that works for the bytemasks without having to * mask them first. */ - return mask * 0x0001020304050608 >> 56; - } else { /* - * Modified Carl Chatfield G+ version for 32-bit * + * return mask * 0x0001020304050608 >> 56; * - * (a) gives us - * -1 (0, ff), 0 (ffff) or 1 (ffffff) - * (b) gives us - * 0 for 0, 1 for (ff ffff ffffff) - * (a+b+1) gives us - * correct 0-3 bytemask count result + * Doing it like this avoids warnings on 32-bit machines. */ - long a = (mask - 256) >> 23; - long b = mask & 1; - return a + b + 1; + long a = (REPEAT_BYTE(0x01) / 0xff + 1); + return mask * a >> (sizeof(long) * 7); + } else { + /* Carl Chatfield / Jan Achrenius G+ version for 32-bit */ + /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */ + long a = (0x0ff0001 + mask) >> 23; + /* Fix the 1 for 00 case */ + return a & mask; } } |