diff --git a/src/hash.cpp b/src/hash.cpp
index 564b9dd..c466789 100644
--- a/src/hash.cpp
+++ b/src/hash.cpp
@@ -1,4 +1,5 @@
 #include "hash.hpp"
+#define XXH_INLINE_ALL
 #include "xxhash.hpp"
 #include <fstream>
 #include <sstream>
@@ -18,7 +19,15 @@ std::string hash_data(const std::string& data) {
 std::string hash_file(const std::string& path) {
     std::ifstream file(path, std::ios::binary);
     if (!file) return "";
-    std::ostringstream oss;
-    oss << file.rdbuf();
-    return hash_data(oss.str());
+    XXH64_state_t* state = XXH64_createState();
+    XXH64_reset(state, 0);
+    char buf[4096];
+    while (file) {
+        file.read(buf, sizeof(buf));
+        std::streamsize n = file.gcount();
+        if (n > 0) XXH64_update(state, buf, static_cast<size_t>(n));
+    }
+    uint64_t h = XXH64_digest(state);
+    XXH64_freeState(state);
+    return to_hex64(h);
 } 
\ No newline at end of file