diff options
Diffstat (limited to 'src/mem/ft_memchr.c')
| -rw-r--r-- | src/mem/ft_memchr.c | 46 |
1 files changed, 38 insertions, 8 deletions
diff --git a/src/mem/ft_memchr.c b/src/mem/ft_memchr.c index 4fd8689..e0266af 100644 --- a/src/mem/ft_memchr.c +++ b/src/mem/ft_memchr.c @@ -6,21 +6,51 @@ /* By: cacharle <marvin@42.fr> +#+ +:+ +#+ */ /* +#+#+#+#+#+ +#+ */ /* Created: 2019/10/07 09:55:31 by cacharle #+# #+# */ -/* Updated: 2020/02/13 04:28:00 by cacharle ### ########.fr */ +/* Updated: 2020/04/01 21:50:49 by charles ### ########.fr */ /* */ /* ************************************************************************** */ #include "libft.h" +/* +** Determining if a long word contain byte n +** +** xor all bytes with n, then check for zero byte like in ft_strlen. +*/ + +#define HIMAGIC 0x8080808080808080L +#define LOMAGIC 0x0101010101010101L + void *ft_memchr(const void *s, int c, size_t n) { - size_t i; - t_ftbyte *cast_s; + uint64_t buf; + uint64_t lw; - cast_s = (t_ftbyte*)s; - i = -1; - while (++i < n) - if (cast_s[i] == (unsigned char)c) - return (cast_s + i); + c = (uint8_t)c; + while (((uint64_t)s & 0b111) != 0) + { + n--; + if (*(uint8_t*)s == (uint8_t)c) + return ((uint8_t*)s); + s++; + } + buf = (uint64_t)c | (uint64_t)c << 8 | (uint64_t)c << 16 + | (uint64_t)c << 24 | (uint64_t)c << 32 | (uint64_t)c << 40 + | (uint64_t)c << 48 | (uint64_t)c << 56; + while (n >= 8) + { + lw = *(uint64_t*)s ^ buf; + if ((lw - LOMAGIC) & ~lw & HIMAGIC) + break ; + n -= 8; + s += 8; + } + while (n > 0) + { + if (*(uint8_t*)s == (uint8_t)c) + return ((uint8_t*)s); + n--; + s++; + } return (NULL); } |