From c161999169c977468fbb36cff852508cef85c3d6 Mon Sep 17 00:00:00 2001
From: david-cortes <david.cortes.rivera@gmail.com>
Date: Wed, 10 Jan 2024 19:28:24 +0100
Subject: [PATCH] user SerializeToBuffer for internal serialization

---
 R-package/src/xgboost_R.cc | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/R-package/src/xgboost_R.cc b/R-package/src/xgboost_R.cc
index b8ad4b229442..63f36ad6a0f2 100644
--- a/R-package/src/xgboost_R.cc
+++ b/R-package/src/xgboost_R.cc
@@ -737,15 +737,13 @@ void XGBAltrepSetPointer(SEXP R_altrepped_obj, BoosterHandle handle) {
   R_RegisterCFinalizerEx(R_ptr, _BoosterFinalizer, TRUE);
 }
 
-const char *ubj_json_format_str = "{\"format\": \"ubj\"}";
-
 SEXP XGBAltrepSerializer_R(SEXP R_altrepped_obj) {
   R_API_BEGIN();
   BoosterHandle handle = R_ExternalPtrAddr(R_altrep_data1(R_altrepped_obj));
   char const *serialized_bytes;
   bst_ulong serialized_length;
-  CHECK_CALL(XGBoosterSaveModelToBuffer(
-    handle, ubj_json_format_str, &serialized_length, &serialized_bytes));
+  CHECK_CALL(XGBoosterSerializeToBuffer(
+    handle, &serialized_length, &serialized_bytes));
   SEXP R_state = Rf_protect(Rf_allocVector(RAWSXP, serialized_length));
   if (serialized_length != 0) {
     std::memcpy(RAW(R_state), serialized_bytes, serialized_length);
@@ -761,9 +759,9 @@ SEXP XGBAltrepDeserializer_R(SEXP unused, SEXP R_state) {
   R_API_BEGIN();
   BoosterHandle handle = nullptr;
   CHECK_CALL(XGBoosterCreate(nullptr, 0, &handle));
-  int res_code = XGBoosterLoadModelFromBuffer(handle,
-                                              RAW(R_state),
-                                              Rf_xlength(R_state));
+  int res_code = XGBoosterUnserializeFromBuffer(handle,
+                                                RAW(R_state),
+                                                Rf_xlength(R_state));
   if (res_code != 0) {
     XGBoosterFree(handle);
   }
@@ -794,14 +792,14 @@ SEXP XGBAltrepDuplicate_R(SEXP R_altrepped_obj, Rboolean deep) {
     SEXP out = Rf_protect(XGBMakeEmptyAltrep());
     char const *serialized_bytes;
     bst_ulong serialized_length;
-    CHECK_CALL(XGBoosterSaveModelToBuffer(
+    CHECK_CALL(XGBoosterSerializeToBuffer(
       R_ExternalPtrAddr(R_altrep_data1(R_altrepped_obj)),
-      ubj_json_format_str, &serialized_length, &serialized_bytes));
+      &serialized_length, &serialized_bytes));
     BoosterHandle new_handle = nullptr;
     CHECK_CALL(XGBoosterCreate(nullptr, 0, &new_handle));
-    int res_code = XGBoosterLoadModelFromBuffer(new_handle,
-                                                serialized_bytes,
-                                                serialized_length);
+    int res_code = XGBoosterUnserializeFromBuffer(new_handle,
+                                                  serialized_bytes,
+                                                  serialized_length);
     if (res_code != 0) {
       XGBoosterFree(new_handle);
     }