Allow creation of string tensor sequence.

onnxruntime/core/session/onnxruntime_c_api.cc

@@ -1108,7 +1108,7 @@ static OrtStatus* OrtCreateValueImplSeqHelper(const OrtValue* const* in, size_t
     }
 
     OrtStatus* st{};
-    utils::MLTypeCallDispatcherRet<OrtStatus*, CallCreateValueImpl, bool, float, double,
+    utils::MLTypeCallDispatcherRet<OrtStatus*, CallCreateValueImpl, bool, float, double, std::string,
                                    MLFloat16, BFloat16, int8_t, uint8_t, int16_t, uint16_t, int32_t, uint32_t, int64_t, uint64_t>
         t_disp(one_tensor.GetElementType());
 

onnxruntime/test/shared_lib/test_nontensor_types.cc

@@ -176,3 +176,42 @@ TEST(CApiTest, CreateGetSeqTensors) {
               std::set<int64_t>(std::begin(vals), std::end(vals)));
   }
 }
+
+TEST(CApiTest, CreateGetSeqStringTensors) {
+  // Creation
+  auto default_allocator = onnxruntime::make_unique<MockedOrtAllocator>();
+  Ort::MemoryInfo info("Cpu", OrtDeviceAllocator, 0, OrtMemTypeDefault);
+
+  std::vector<Ort::Value> in;
+  const char* string_input_data[] = {"abs", "def"};
+  const int N = 2;
+  for (int i = 0; i < N; ++i) {
+    // create tensor
+    std::vector<int64_t> shape{2};
+    auto value = Ort::Value::CreateTensor(Ort::AllocatorWithDefaultOptions(), shape.data(), shape.size(), ONNXTensorElementDataType::ONNX_TENSOR_ELEMENT_DATA_TYPE_STRING);
+
+    Ort::GetApi().FillStringTensor(value, string_input_data, 2);
+    in.push_back(std::move(value));
+  }
+
+  Ort::Value seq_ort = Ort::Value::CreateSequence(in);
+
+  // Fetch
+  std::set<std::string> string_set;
+  for (int idx = 0; idx < N; ++idx) {
+    Ort::Value out = seq_ort.GetValue(idx, default_allocator.get());
+    size_t data_len = out.GetStringTensorDataLength();
+    std::string result(data_len, '\0');
+    std::vector<size_t> offsets(N);
+    out.GetStringTensorContent((void*)result.data(), data_len, offsets.data(), offsets.size());
+
+    const char* s = result.data();
+    for (size_t i = 0; i < offsets.size(); ++i) {
+      size_t start = offsets[i];
+      size_t count = (i + 1) < offsets.size() ? offsets[i + 1] - start : data_len - start;
+      std::string stemp(s + start, count);
+      string_set.insert(stemp);
+    }
+  }
+  ASSERT_EQ(string_set, std::set<std::string>(std::begin(string_input_data), std::end(string_input_data)));
+}