CString: Add strnlen() and strndup()

luna/include/luna/CString.h

@@ -7,12 +7,16 @@ extern "C"
     void* memset(void* buf, int c, usize n);
     int memcmp(const void* a, const void* b, usize n);
     void* memmove(void* dest, const void* src, usize n);
+
     usize strlen(const char* str);
+    usize strnlen(const char* str, usize max);
+
     int strcmp(const char* a, const char* b);
 
     usize wcslen(const wchar_t* str);
 
     char* strdup(const char* str);
+    char* strndup(const char* str, usize max);
 
     // Copies len bytes from src into dest and adds a null terminator.
     // FIXME: Replace this invented function with strlcpy().

luna/src/CString.cpp

@@ -46,6 +46,14 @@ extern "C"
         return (usize)(i - str);
     }
 
+    usize strnlen(const char* str, usize max)
+    {
+        const char* i = str;
+        for (; max, *i; ++i, --max)
+            ;
+        return (usize)(i - str);
+    }
+
     int strcmp(const char* a, const char* b)
     {
         while (*a && (*a == *b))
@@ -68,10 +76,22 @@ extern "C"
     {
         const usize len = strlen(str);
 
-        char* dest = (char*)malloc_impl(len + 1).value_or(nullptr);
+        char* dest = (char*)calloc_impl(len + 1, 1).value_or(nullptr);
         if (!dest) return nullptr;
 
-        memcpy(dest, str, len + 1);
+        memcpy(dest, str, len);
+
+        return dest;
+    }
+
+    char* strndup(const char* str, usize max)
+    {
+        const usize len = strnlen(str, max);
+
+        char* dest = (char*)calloc_impl(len + 1, 1).value_or(nullptr);
+        if (!dest) return nullptr;
+
+        memcpy(dest, str, len);
 
         return dest;
     }