mostly improvements to malloc

kernel/vga.c

@@ -1,9 +1,9 @@
 #include "vga.h"
 #include <stddef.h>
 #include <stdbool.h>
-#include <stdio.h>   // Include for vsnprintf
-#include <string.h>  // Include for strlen
-#include <stdarg.h>  // Include for va_list, va_start, etc.
+#include <string.h>
+#include <stdarg.h>
+#include "string_utils.h"
 
 void outb(uint16_t port, uint8_t value) {
     __asm__ volatile("outb %0, %1" : : "a"(value), "Nd"(port));
@@ -130,11 +130,11 @@ void vga_printf(const char* format, ...) {
     char buffer[256];  // Buffer to store the formatted string
     va_list args;
     va_start(args, format);
-    vsnprintf(buffer, sizeof(buffer), format, args);
+    my_vsnprintf(buffer, sizeof(buffer), format, args); // Use my_vsnprintf instead of vsnprintf
     va_end(args);
     
     // Now you can use the buffer with vga_write_string
-    vga_write_string(buffer, strlen(buffer));
+    vga_write_string(buffer, my_strlen(buffer)); // Use my_strlen instead of strlen
 }
 
 void vga_init(void) {