string: split strcmp and strncmp (DONE)

CMakeLists.txt

@@ -142,6 +142,7 @@ set(SOURCES
   src/libc/string/strcpy.c
   src/libc/string/strdup.c
   src/libc/string/strlen.c
+  src/libc/string/strncmp.c
   src/libc/string/strnlen.c
   src/libc/string/strrchr.c)
 

src/libc/string/strcmp.c

@@ -1,40 +1,10 @@
 #include <string.h>
 
-/*
-** The strcmp() function compares the two strings s1 and s2. The locale is not
-** taken into account (for a locale-aware comparison, see strcoll(3)).
-** The comparison is done using unsigned characters.
-**
-** strcmp() returns an integer indicating the result of the comparison, as follows:
-**   * 0, if the s1 and s2 are equal;
-**   * a negative value if s1 is less than s2;
-**   * a positive value if s1 is greater than s2.
-**
-** TODO: quad-word access !
-*/
 int strcmp(const char *s1, const char *s2)
 {
-	if (s1 == NULL || s2 == NULL)
-		return (0);
 	while (*s1 != '\0' && *s2 != '\0' && *s1 == *s2) {
 		s1 += 1;
 		s2 += 1;
 	}
 	return (*s1 - *s2);
 }
-
-/*
-** The strncmp() function is similar, except it compares only the first (at most)
-** n bytes of s1 and s2.
-**
-** TODO: quad-word access !
-*/
-int strncmp(const char *s1, const char *s2, size_t n)
-{
-	if (s1 == NULL || s2 == NULL || n == 0)
-		return (0);
-	size_t i = -1;
-	while (++i < n - 1 && s1[i] != '\0' && s2[i] != '\0'
-	       && s1[i] == s2[i]) ;
-	return (s1[i] - s2[i]);
-}

src/libc/string/strncmp.c

@@ -0,0 +1,11 @@
+#include <string.h>
+
+int strncmp(const char *s1, const char *s2, size_t n)
+{
+	if (n == 0)
+		return (0);
+	size_t i = -1;
+	while (++i < n - 1 && s1[i] != '\0' && s2[i] != '\0'
+	       && s1[i] == s2[i]) ;
+	return (s1[i] - s2[i]);
+}