Conformity of memset/memcpy ; implement memmove/memcmp.

2 files changed, 31 insertions, 8 deletions

diff --git a/kernel/include/string.h b/kernel/include/string.h
index 1eb3eef..3cb0db3 100644
--- a/kernel/include/string.h
+++ b/kernel/include/string.h
@@ -3,8 +3,10 @@
 #include <stddef.h>
 #include <stdint.h>
 
-void *memcpy(void *dest, const void *src, int count);
-void *memset(void *dest, int val, int count);
+void *memcpy(void *dest, const void *src, size_t count);
+void *memset(void *dest, int val, size_t count);
+int memcmp(const void *s1, const void *s2, size_t n);
+void *memmove(void *dest, const void *src, size_t count);
 
 size_t strlen(const char *str);
 char *strchr(const char *str, char c);
diff --git a/kernel/lib/string.c b/kernel/lib/string.c
index da8f60e..6d26478 100644
--- a/kernel/lib/string.c
+++ b/kernel/lib/string.c
@@ -38,12 +38,12 @@ int strcmp(const char *s1, const char *s2) {
 		s1++;
 		s2++;
 	}
-	return (* (unsigned char*)s1 - *(unsigned char*)s2);
+	return (*(unsigned char*)s1 - *(unsigned char*)s2);
 }
 
-void *memcpy(void *vd, const void *vs, int count) {
+void *memcpy(void *vd, const void *vs, size_t count) {
 	uint8_t *dest = (uint8_t*)vd, *src = (uint8_t*)vs;
-	int f = count % 4, n = count / 4, i;
+	size_t f = count % 4, n = count / 4, i;
 	const uint32_t* s = (uint32_t*)src;
 	uint32_t* d = (uint32_t*)dest;
 	for (i = 0; i < n; i++) {
@@ -57,10 +57,31 @@ void *memcpy(void *vd, const void *vs, int count) {
 	return vd;
 }
 
-void *memset(void *dest, int val, int count) {
+void *memmove(void *vd, const void *vs, size_t count) {
+	uint8_t *dest = (uint8_t*)vd, *src = (uint8_t*)vs;
+
+	if (vd < vs) {
+		for (size_t i = 0; i < count; i++)
+			dest[i] = src[i];
+	} else {
+		for (size_t i = 0; i < count; i++)
+			dest[count - i] = src[count - i];
+	}
+	return vd;
+}
+
+int memcmp(const void *va, const void *vb, size_t count) {
+	uint8_t *a = (uint8_t*)va;
+	uint8_t *b = (uint8_t*)vb;
+	for (size_t i = 0; i < count; i++) {
+		if (a[i] != b[i]) return (int)a[i] - (int)b[i];
+	}
+	return 0;
+}
+
+void *memset(void *dest, int val, size_t count) {
 	uint8_t *dest_c = (uint8_t*)dest;
-	int i;
-	for (i = 0; i < count; i++) {
+	for (size_t i = 0; i < count; i++) {
 		dest_c[i] = val;
 	}
 	return dest;