feature (kernel utils): implemented octal_string to integer conversion

kernel/inc/utils/math.h

@@ -25,6 +25,7 @@
 #define NOX_MATH_H
 
 #include "stdtypes.h"
+#include "string.h"
 
 #define MAX(a, b)       (a > b ? a : b)
 #define MIN(a, b)       (a > b ? b : a)
@@ -38,5 +39,6 @@ typedef struct {
 
 uint64_t pow                    (uint64_t base, uint64_t exp);
 uint64_t abs                    (int64_t n);
+uint64_t octal_string_to_int    (string_t string, uint8_t size);
 
 #endif //NOX_MATH_H

kernel/src/utils/math.c

@@ -37,3 +37,12 @@ uint64_t abs(int64_t n) {
     }
     return n;
 }
+
+uint64_t octal_string_to_int(string_t string, uint8_t size) {
+    uint64_t n = 0;
+    for (int i = 0; i < size; i++) {
+        n *= 8;
+        n += string[i] - '0';
+    }
+    return n;
+}