First commit

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 46 insertions, 0 deletions

diff --git a/libautomata_compile_kmp_automaton.c b/libautomata_compile_kmp_automaton.c
new file mode 100644
index 0000000..3917b00
--- /dev/null
+++ b/libautomata_compile_kmp_automaton.c
@@ -0,0 +1,46 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+LIBAUTOMATA_KMP_AUTOMATON *
+libautomata_compile_kmp_automaton(const void *pattern, size_t length, size_t elemsize)
+{
+	size_t i = 0, j = SIZE_MAX;
+	size_t size = sizeof_kmp_automaton(length, elemsize);
+	LIBAUTOMATA_KMP_AUTOMATON *ret = malloc(size);
+
+	if (!ret)
+		return NULL;
+
+	ret->position = 0;
+	ret->length = length;
+	ret->elemsize = elemsize;
+	memcpy((void *)&ret->next[length + 1U], pattern, length * elemsize);
+
+#define INTRINSIC(TYPE)\
+	(((const TYPE *)pattern)[i] == ((const TYPE *)pattern)[j])
+
+#define MEMCMP(WIDTH)\
+	(!memcmp(&((const char *)pattern)[i * (WIDTH)], &((const char *)pattern)[j * (WIDTH)], (WIDTH)))
+
+#define IMPLEMENT(EQ, EQ_PARAM, CASE)\
+	while (i < length) {\
+		if (j != SIZE_MAX && !(EQ(EQ_PARAM)))\
+			j = ret->next[j];\
+		i++;\
+		j++;\
+		if (EQ(EQ_PARAM))\
+			ret->next[i] = ret->next[j];\
+		else CASE:\
+			ret->next[i] = j;\
+	}\
+	return ret
+
+	switch (elemsize) {
+		IMPLEMENT(INTRINSIC, uint8_t, case sizeof(uint8_t));
+		IMPLEMENT(INTRINSIC, uint16_t, case sizeof(uint16_t));
+		IMPLEMENT(INTRINSIC, uint32_t, case sizeof(uint32_t));
+		IMPLEMENT(INTRINSIC, uint64_t, case sizeof(uint64_t));
+		IMPLEMENT(MEMCMP, elemsize, default);
+	}
+}