[R] fix EncodeChar

src/c_api.cpp

@@ -273,23 +273,21 @@ public:
     return ret;
   }
 
-  #pragma warning(disable : 4996)
   int GetEvalNames(char** out_strs) const {
     int idx = 0;
     for (const auto& metric : train_metric_) {
       for (const auto& name : metric->GetName()) {
-        std::strcpy(out_strs[idx], name.c_str());
+        std::memcpy(out_strs[idx], name.c_str(), name.size() + 1);
         ++idx;
       }
     }
     return idx;
   }
 
-  #pragma warning(disable : 4996)
   int GetFeatureNames(char** out_strs) const {
     int idx = 0;
     for (const auto& name : boosting_->FeatureNames()) {
-      std::strcpy(out_strs[idx], name.c_str());
+      std::memcpy(out_strs[idx], name.c_str(), name.size() + 1);
       ++idx;
     }
     return idx;
@@ -719,7 +717,6 @@ int LGBM_DatasetSetFeatureNames(
   API_END();
 }
 
-#pragma warning(disable : 4996)
 int LGBM_DatasetGetFeatureNames(
   DatasetHandle handle,
   char** feature_names,
@@ -729,7 +726,7 @@ int LGBM_DatasetGetFeatureNames(
   auto inside_feature_name = dataset->feature_names();
   *num_feature_names = static_cast<int>(inside_feature_name.size());
   for (int i = 0; i < *num_feature_names; ++i) {
-    std::strcpy(feature_names[i], inside_feature_name[i].c_str());
+    std::memcpy(feature_names[i], inside_feature_name[i].c_str(), inside_feature_name[i].size() + 1);
   }
   API_END();
 }
@@ -1138,7 +1135,6 @@ int LGBM_BoosterSaveModel(BoosterHandle handle,
   API_END();
 }
 
-#pragma warning(disable : 4996)
 int LGBM_BoosterSaveModelToString(BoosterHandle handle,
                                   int num_iteration,
                                   int64_t buffer_len, 
@@ -1149,12 +1145,11 @@ int LGBM_BoosterSaveModelToString(BoosterHandle handle,
   std::string model = ref_booster->SaveModelToString(num_iteration);
   *out_len = static_cast<int64_t>(model.size()) + 1;
   if (*out_len <= buffer_len) {
-    std::strcpy(out_str, model.c_str());
+    std::memcpy(out_str, model.c_str(), *out_len);
   }
   API_END();
 }
 
-#pragma warning(disable : 4996)
 int LGBM_BoosterDumpModel(BoosterHandle handle,
                           int num_iteration,
                           int64_t buffer_len,
@@ -1165,7 +1160,7 @@ int LGBM_BoosterDumpModel(BoosterHandle handle,
   std::string model = ref_booster->DumpModel(num_iteration);
   *out_len = static_cast<int64_t>(model.size()) + 1;
   if (*out_len <= buffer_len) {
-    std::strcpy(out_str, model.c_str());
+    std::memcpy(out_str, model.c_str(), *out_len);
   }
   API_END();
 }

src/lightgbm_R.cpp

@@ -33,15 +33,14 @@
 using namespace LightGBM;
 
 LGBM_SE EncodeChar(LGBM_SE dest, const char* src, LGBM_SE buf_len, LGBM_SE actual_len) {
-  int str_len = static_cast<int>(std::strlen(src));
-  R_INT_PTR(actual_len)[0] = str_len;
+  size_t str_len = std::strlen(src);
+  if (str_len > INT32_MAX) {
+    Log::Fatal("Don't support large string in R-package.");
+  }
+  R_INT_PTR(actual_len)[0] = static_cast<int>(str_len);
   if (R_AS_INT(buf_len) < str_len) { return dest; }
   auto ptr = R_CHAR_PTR(dest);
-  int i = 0;
-  while (src[i] != '\0') {
-    ptr[i] = src[i];
-    ++i;
-  }
+  std::memcpy(ptr, src, str_len);
   return dest;
 }
 
@@ -604,15 +603,7 @@ LGBM_SE LGBM_BoosterSaveModelToString_R(LGBM_SE handle,
   int64_t out_len = 0;
   std::vector<char> inner_char_buf(R_AS_INT(buffer_len));
   CHECK_CALL(LGBM_BoosterSaveModelToString(R_GET_PTR(handle), R_AS_INT(num_iteration), R_AS_INT(buffer_len), &out_len, inner_char_buf.data()));
-  if (out_len < R_AS_INT(buffer_len)) {
-    EncodeChar(out_str, inner_char_buf.data(), buffer_len, actual_len);
-  } else {
-    if (out_len <= INT32_MAX) {
-      R_INT_PTR(actual_len)[0] = static_cast<int>(out_len);
-    } else {
-      Log::Fatal("Don't support large model in R package.");
-    }
-  }
+  EncodeChar(out_str, inner_char_buf.data(), buffer_len, actual_len);
   R_API_END();
 }
 
@@ -626,14 +617,6 @@ LGBM_SE LGBM_BoosterDumpModel_R(LGBM_SE handle,
   int64_t out_len = 0;
   std::vector<char> inner_char_buf(R_AS_INT(buffer_len));
   CHECK_CALL(LGBM_BoosterDumpModel(R_GET_PTR(handle), R_AS_INT(num_iteration), R_AS_INT(buffer_len), &out_len, inner_char_buf.data()));
-  if (out_len < R_AS_INT(buffer_len)) {
-    EncodeChar(out_str, inner_char_buf.data(), buffer_len, actual_len);
-  } else {
-    if (out_len <= INT32_MAX) {
-      R_INT_PTR(actual_len)[0] = static_cast<int>(out_len);
-    } else {
-      Log::Fatal("Don't support large model in R package.");
-    }
-  }
+  EncodeChar(out_str, inner_char_buf.data(), buffer_len, actual_len);
   R_API_END();
 }