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/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* ft_memmem.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: cacharle <marvin@42.fr> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2020/02/13 01:54:55 by cacharle #+# #+# */
/* Updated: 2020/02/13 03:13:23 by cacharle ### ########.fr */
/* */
/* ************************************************************************** */
#include "libft_mem.h"
#define BAD_TABLE_SIZE 256
static void st_bad_table_init(size_t bad_table[BAD_TABLE_SIZE],
const char *little, size_t little_len)
{
size_t i;
ft_memset_pattern4(bad_table, &little_len, 4 * BAD_TABLE_SIZE);
i = 0;
while (i < little_len)
{
bad_table[(int)little[i]] = little_len - i - 1;
i++;
}
}
static t_ftbool st_memcmp_end(const void *s1, const void *s2, size_t n)
{
while (n-- > 0)
if (((t_ftbyte*)s1)[n] != ((t_ftbyte*)s2)[n])
return (FALSE);
return (TRUE);
}
void *ft_memmem(const void *big, size_t big_len,
const void *little, size_t little_len)
{
size_t i;
size_t bad_table[BAD_TABLE_SIZE];
st_bad_table_init(bad_table, little, little_len);
i = 0;
while (i < big_len - little_len)
{
if (st_memcmp_end((t_ftbyte*)big + i, little, little_len))
return ((t_ftbyte*)big + i);
i += bad_table[(int)(((t_ftbyte*)big)[i + big_len] - 1)];
}
return (NULL);
}
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