still working on a more robust vfs

kernel/lib/strtok.c

@@ -2,63 +2,64 @@
 
 #include <stddef.h>
 
-char* strtok_r(char *s, const char *delim, char **saveptr) {
+static size_t kernel_strspn(const char *s, const char *accept) {
+    const char *p;
+    const char *a;
+    size_t count = 0;
+
+    for (p = s; *p != '\0'; ++p) {
+        for (a = accept; *a != '\0'; ++a) {
+            if (*p == *a)
+                break;
+        }
+        if (*a == '\0')
+            return count;
+        ++count;
+    }
+    return count;
+}
+
+static char *kernel_strpbrk(const char *s, const char *accept) {
+    while (*s != '\0') {
+        const char *a = accept;
+        while (*a != '\0') {
+            if (*s == *a) {
+                return (char *)s;
+            }
+            a++;
+        }
+        s++;
+    }
+    return NULL;
+}
+
+char *strtok_r(char *str, const char *delim, char **saveptr) {
     char *token;
 
-    if (!saveptr) {
+    if (str == NULL) {
+        str = *saveptr;
+    }
+
+    if (str == NULL || *str == '\0') {
+        *saveptr = NULL;
         return NULL;
     }
 
-    if (!s) {
-        s = *saveptr;
-    }
-
-    if (!s || *s == '\0') {
-        *saveptr = s;
+    str += kernel_strspn(str, delim);
+    if (*str == '\0') {
+        *saveptr = NULL;
         return NULL;
     }
 
-    while (*s != '\0') {
-        const char *d = delim;
-        int is_delim = 0;
-        while (*d != '\0') {
-            if (*s == *d) {
-                is_delim = 1;
-                break;
-            }
-            d++;
-        }
-        if (!is_delim) {
-            break;
-        }
-        s++;
+    token = str;
+    str = kernel_strpbrk(token, delim);
+    
+    if (str == NULL) {
+        *saveptr = NULL;
+    } else {
+        *str = '\0';
+        *saveptr = str + 1;
     }
 
-    if (*s == '\0') {
-        *saveptr = s;
-        return NULL;
-    }
-
-    token = s;
-
-    while (*s != '\0') {
-        const char *d = delim;
-        int is_delim = 0;
-        while (*d != '\0') {
-            if (*s == *d) {
-                is_delim = 1;
-                break;
-            }
-            d++;
-        }
-        if (is_delim) {
-            *s = '\0';
-            *saveptr = s + 1;
-            return token;
-        }
-        s++;
-    }
-
-    *saveptr = s;
     return token;
 }