From ae89f342b51cb4ef71f18e89b74585cd61b05a60 Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Wed, 17 Dec 2025 16:20:43 +0100 Subject: First commit MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- libautomata_execute_kmp_automaton.c | 40 +++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 libautomata_execute_kmp_automaton.c (limited to 'libautomata_execute_kmp_automaton.c') diff --git a/libautomata_execute_kmp_automaton.c b/libautomata_execute_kmp_automaton.c new file mode 100644 index 0000000..69ffcce --- /dev/null +++ b/libautomata_execute_kmp_automaton.c @@ -0,0 +1,40 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" + + +void * +libautomata_execute_kmp_automaton(const void *haystack, size_t length, LIBAUTOMATA_KMP_AUTOMATON *automaton) +{ + const void *pattern = (void *)&automaton->next[automaton->length + 1U]; + size_t i = 0; + +#define INTRINSIC(TYPE)\ + (((const TYPE *)pattern)[automaton->position] == ((const TYPE *)haystack)[i]) + +#define MEMCMP(WIDTH)\ + (!memcmp(&((const char *)pattern)[automaton->position * automaton->elemsize],\ + &((const char *)haystack)[i * automaton->elemsize],\ + automaton->elemsize)) + +#define IMPLEMENT(EQ, EQ_PARAM)\ + while (i < length) {\ + while (automaton->position != SIZE_MAX && !(EQ(EQ_PARAM)))\ + automaton->position = automaton->next[automaton->position];\ + i++;\ + if (++automaton->position == automaton->length)\ + goto found;\ + }\ + return NULL + + switch (automaton->elemsize) { + case sizeof(uint8_t): IMPLEMENT(INTRINSIC, uint8_t); + case sizeof(uint16_t): IMPLEMENT(INTRINSIC, uint16_t); + case sizeof(uint32_t): IMPLEMENT(INTRINSIC, uint32_t); + case sizeof(uint64_t): IMPLEMENT(INTRINSIC, uint64_t); + default: IMPLEMENT(MEMCMP, elemsize); + } + +found: + automaton->position = automaton->next[automaton->position]; + return &(*(char **)(void *)&haystack)[i]; +} -- cgit v1.2.3-70-g09d2