From c128213daa677d548bfc2905496257fe4a4faf79 Mon Sep 17 00:00:00 2001 From: Charles Date: Wed, 11 Mar 2020 21:07:32 +0100 Subject: ft_mem* and ft_strlen optimization --- src/mem/ft_memchr.c | 44 +++++++++++++++++++++++++++++++++++++------- 1 file changed, 37 insertions(+), 7 deletions(-) (limited to 'src/mem/ft_memchr.c') diff --git a/src/mem/ft_memchr.c b/src/mem/ft_memchr.c index 4fd8689..54780fe 100644 --- a/src/mem/ft_memchr.c +++ b/src/mem/ft_memchr.c @@ -12,15 +12,45 @@ #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); } -- cgit From d4aeabeac0a8bd1665b14aacf487df17198c1ab9 Mon Sep 17 00:00:00 2001 From: Charles Date: Tue, 12 May 2020 21:40:41 +0200 Subject: Fixing/refactoring ft_getline, fixed/normed ft_memchr, added ft_strmove --- src/mem/ft_memchr.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) (limited to 'src/mem/ft_memchr.c') diff --git a/src/mem/ft_memchr.c b/src/mem/ft_memchr.c index e0266af..848b436 100644 --- a/src/mem/ft_memchr.c +++ b/src/mem/ft_memchr.c @@ -6,7 +6,7 @@ /* By: cacharle +#+ +:+ +#+ */ /* +#+#+#+#+#+ +#+ */ /* Created: 2019/10/07 09:55:31 by cacharle #+# #+# */ -/* Updated: 2020/04/01 21:50:49 by charles ### ########.fr */ +/* Updated: 2020/05/12 21:39:04 by charles ### ########.fr */ /* */ /* ************************************************************************** */ @@ -27,16 +27,15 @@ void *ft_memchr(const void *s, int c, size_t n) uint64_t lw; c = (uint8_t)c; - while (((uint64_t)s & 0b111) != 0) + while (((uint64_t)s & 0b111) != 0 && n > 0) { - n--; if (*(uint8_t*)s == (uint8_t)c) - return ((uint8_t*)s); + return ((void*)s); + n--; 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; + buf = c | c << 8 | c << 16 | c << 24; + buf |= buf << 32; while (n >= 8) { lw = *(uint64_t*)s ^ buf; @@ -45,12 +44,8 @@ void *ft_memchr(const void *s, int c, size_t n) n -= 8; s += 8; } - while (n > 0) - { - if (*(uint8_t*)s == (uint8_t)c) - return ((uint8_t*)s); - n--; - s++; - } + while (n-- > 0) + if (*(uint8_t*)s++ == (uint8_t)c) + return ((void*)(s - 1)); return (NULL); } -- cgit