fix save_model_to_string for large model (#1080)

* use int64 for string

* [R] Fatal when CSC exceed int32.max

R-package/R/lgb.Dataset.R

@@ -193,7 +193,9 @@ Dataset <- R6Class(
                              ref_handle)
           
         } else if (is(private$raw_data, "dgCMatrix")) {
-          
+          if (length(private$raw_data@p) > 2147483647) {
+            stop("Cannot support large CSC matrix")
+          }
           # Are we using a dgCMatrix (sparsed matrix column compressed)
           handle <- lgb.call("LGBM_DatasetCreateFromCSC_R",
                              ret = handle,

R-package/R/lgb.Predictor.R

@@ -127,7 +127,9 @@ Predictor <- R6Class(
                             private$params)
           
         } else if (is(data, "dgCMatrix")) {
-          
+          if (length(data@p) > 2147483647) {
+            stop("Cannot support large CSC matrix")
+          }
           # Check if data is a dgCMatrix (sparse matrix, column compressed format)
           preds <- lgb.call("LGBM_BoosterPredictForCSC_R",
                             ret = preds,

include/LightGBM/c_api.h

@@ -677,8 +677,8 @@ LIGHTGBM_C_EXPORT int LGBM_BoosterSaveModel(BoosterHandle handle,
 */
 LIGHTGBM_C_EXPORT int LGBM_BoosterSaveModelToString(BoosterHandle handle,
                                                     int num_iteration,
-                                                    int buffer_len,
-                                                    int* out_len,
+                                                    int64_t buffer_len,
+                                                    int64_t* out_len,
                                                     char* out_str);
 
 /*!
@@ -692,8 +692,8 @@ LIGHTGBM_C_EXPORT int LGBM_BoosterSaveModelToString(BoosterHandle handle,
 */
 LIGHTGBM_C_EXPORT int LGBM_BoosterDumpModel(BoosterHandle handle,
                                             int num_iteration,
-                                            int buffer_len,
-                                            int* out_len,
+                                            int64_t buffer_len,
+                                            int64_t* out_len,
                                             char* out_str);
 
 /*!

python-package/lightgbm/basic.py

@@ -1668,13 +1668,13 @@ class Booster(object):
         if num_iteration <= 0:
             num_iteration = self.best_iteration
         buffer_len = 1 << 20
-        tmp_out_len = ctypes.c_int(0)
+        tmp_out_len = ctypes.c_int64(0)
         string_buffer = ctypes.create_string_buffer(buffer_len)
         ptr_string_buffer = ctypes.c_char_p(*[ctypes.addressof(string_buffer)])
         _safe_call(_LIB.LGBM_BoosterSaveModelToString(
             self.handle,
             ctypes.c_int(num_iteration),
-            ctypes.c_int(buffer_len),
+            ctypes.c_int64(buffer_len),
             ctypes.byref(tmp_out_len),
             ptr_string_buffer))
         actual_len = tmp_out_len.value
@@ -1685,7 +1685,7 @@ class Booster(object):
             _safe_call(_LIB.LGBM_BoosterSaveModelToString(
                 self.handle,
                 ctypes.c_int(num_iteration),
-                ctypes.c_int(actual_len),
+                ctypes.c_int64(actual_len),
                 ctypes.byref(tmp_out_len),
                 ptr_string_buffer))
         return string_buffer.value.decode()
@@ -1707,13 +1707,13 @@ class Booster(object):
         if num_iteration <= 0:
             num_iteration = self.best_iteration
         buffer_len = 1 << 20
-        tmp_out_len = ctypes.c_int(0)
+        tmp_out_len = ctypes.c_int64(0)
         string_buffer = ctypes.create_string_buffer(buffer_len)
         ptr_string_buffer = ctypes.c_char_p(*[ctypes.addressof(string_buffer)])
         _safe_call(_LIB.LGBM_BoosterDumpModel(
             self.handle,
             ctypes.c_int(num_iteration),
-            ctypes.c_int(buffer_len),
+            ctypes.c_int64(buffer_len),
             ctypes.byref(tmp_out_len),
             ptr_string_buffer))
         actual_len = tmp_out_len.value
@@ -1724,7 +1724,7 @@ class Booster(object):
             _safe_call(_LIB.LGBM_BoosterDumpModel(
                 self.handle,
                 ctypes.c_int(num_iteration),
-                ctypes.c_int(actual_len),
+                ctypes.c_int64(actual_len),
                 ctypes.byref(tmp_out_len),
                 ptr_string_buffer))
         return json.loads(string_buffer.value.decode())

src/c_api.cpp

@@ -1140,13 +1140,13 @@ int LGBM_BoosterSaveModel(BoosterHandle handle,
 #pragma warning(disable : 4996)
 int LGBM_BoosterSaveModelToString(BoosterHandle handle,
                                   int num_iteration,
-                                  int buffer_len,
-                                  int* out_len,
+                                  int64_t buffer_len, 
+                                  int64_t* out_len,
                                   char* out_str) {
   API_BEGIN();
   Booster* ref_booster = reinterpret_cast<Booster*>(handle);
   std::string model = ref_booster->SaveModelToString(num_iteration);
-  *out_len = static_cast<int>(model.size()) + 1;
+  *out_len = static_cast<int64_t>(model.size()) + 1;
   if (*out_len <= buffer_len) {
     std::strcpy(out_str, model.c_str());
   }
@@ -1156,13 +1156,13 @@ int LGBM_BoosterSaveModelToString(BoosterHandle handle,
 #pragma warning(disable : 4996)
 int LGBM_BoosterDumpModel(BoosterHandle handle,
                           int num_iteration,
-                          int buffer_len,
-                          int* out_len,
+                          int64_t buffer_len,
+                          int64_t* out_len,
                           char* out_str) {
   API_BEGIN();
   Booster* ref_booster = reinterpret_cast<Booster*>(handle);
   std::string model = ref_booster->DumpModel(num_iteration);
-  *out_len = static_cast<int>(model.size()) + 1;
+  *out_len = static_cast<int64_t>(model.size()) + 1;
   if (*out_len <= buffer_len) {
     std::strcpy(out_str, model.c_str());
   }

src/lightgbm_R.cpp

@@ -601,14 +601,17 @@ LGBM_SE LGBM_BoosterSaveModelToString_R(LGBM_SE handle,
   LGBM_SE out_str,
   LGBM_SE call_state) {
   R_API_BEGIN();
-  int out_len = 0;
+  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()));
-  EncodeChar(out_str, inner_char_buf.data(), buffer_len, actual_len);
   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.");
+    }
   }
   R_API_END();
 }
@@ -620,14 +623,17 @@ LGBM_SE LGBM_BoosterDumpModel_R(LGBM_SE handle,
   LGBM_SE out_str,
   LGBM_SE call_state) {
   R_API_BEGIN();
-  int out_len = 0;
+  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()));
-  EncodeChar(out_str, inner_char_buf.data(), buffer_len, actual_len);
   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.");
+    }
   }
   R_API_END();
 }