diff --git a/lib/glacier/string/string.cpp b/lib/glacier/string/string.cpp
index c7d3a35..4e193d1 100644
--- a/lib/glacier/string/string.cpp
+++ b/lib/glacier/string/string.cpp
@@ -14,12 +14,14 @@ uint64_t cstrlen(const char* cstr) {
 
 }  // namespace
 
-String::String(const char* str) {
-  length_ = cstrlen(str);
+String::String(const char* str) : String(str, cstrlen(str)) {}
+
+String::String(const char* cstr, uint64_t str_len) : length_(str_len) {
   cstr_ = new char[length_ + 1];
-  for (uint64_t i = 0; i <= length_; i++) {
-    cstr_[i] = str[i];
+  for (uint64_t i = 0; i < length_; i++) {
+    cstr_[i] = cstr[i];
   }
+  cstr_[length_] = '\0';
 }
 
 bool String::operator==(const String& other) {
diff --git a/lib/glacier/string/string.h b/lib/glacier/string/string.h
index 458ecb5..e919a7c 100644
--- a/lib/glacier/string/string.h
+++ b/lib/glacier/string/string.h
@@ -7,6 +7,7 @@ namespace glcr {
 class String {
  public:
   String(const char* cstr);
+  String(const char* cstr, uint64_t str_len);
 
   const char* cstr() const { return cstr_; }
   uint64_t length() const { return length_; }