Starting Point

lib/mem.c

@@ -0,0 +1,59 @@
+#include <string.h>
+
+int memcmp(const void *s1, const void *s2, size_t n)
+{
+	const unsigned char *str1 = s1;
+	const unsigned char *str2 = s2;
+	int		     res  = 0;
+	while (n > 0 && res == 0) {
+		res = *str1 - *str2;
+		str1++;
+		str2++;
+		n--;
+	}
+	return res;
+}
+
+void *memcpy(void *restrict s1, const void *restrict s2, size_t n)
+{
+	char *restrict str1	  = s1;
+	const char *restrict str2 = s2;
+	while (n > 0) {
+		*str1 = *str2;
+		str1++;
+		str2++;
+		n--;
+	}
+	return s1;
+}
+
+void *memmove(void *s1, const void *s2, size_t n)
+{
+	char	   *str1 = s1;
+	const char *str2 = s2;
+	if (str1 < str2) {
+		while (n > 0) {
+			*str1 = *str2;
+			str1++;
+			str2++;
+			n--;
+		}
+	} else {
+		while (n > 0) {
+			n--;
+			*(str1 + n) = *(str2 + n);
+		}
+	}
+	return s1;
+}
+
+void *memset(void *s, int c, size_t n)
+{
+	unsigned char *str = s;
+	while (n > 0) {
+		*str = (unsigned char)c;
+		str++;
+		n--;
+	}
+	return s;
+}