1/* Copyright 2016 The TensorFlow Authors. All Rights Reserved.
2
3Licensed under the Apache License, Version 2.0 (the "License");
4you may not use this file except in compliance with the License.
5You may obtain a copy of the License at
6
7 http://www.apache.org/licenses/LICENSE-2.0
8
9Unless required by applicable law or agreed to in writing, software
10distributed under the License is distributed on an "AS IS" BASIS,
11WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12See the License for the specific language governing permissions and
13limitations under the License.
14==============================================================================*/
15
16// See docs in ../ops/string_ops.cc.
17
18#include <string>
19
20#include "tensorflow/core/framework/kernel_def_builder.h"
21#include "tensorflow/core/framework/op_kernel.h"
22#include "tensorflow/core/framework/tensor.h"
23#include "tensorflow/core/lib/core/errors.h"
24#include "tensorflow/core/lib/core/status.h"
25#include "tensorflow/core/lib/strings/str_util.h"
26
27namespace tensorflow {
28
29class StringJoinOp : public OpKernel {
30 public:
31 using OpKernel::OpKernel;
32
33 explicit StringJoinOp(OpKernelConstruction* ctx) : OpKernel(ctx) {
34 OP_REQUIRES_OK(ctx, ctx->GetAttr("separator", &separator_));
35 }
36
37 void Compute(OpKernelContext* context) override {
38 OpInputList input_list;
39 OP_REQUIRES_OK(context, context->input_list("inputs", &input_list));
40 TensorShape input_shape;
41 std::vector<bool> is_scalar;
42 std::vector<TTypes<tstring>::ConstFlat> inputs;
43
44 for (const auto& input : input_list) {
45 inputs.push_back(input.flat<tstring>());
46 is_scalar.push_back(TensorShapeUtils::IsScalar(input.shape()));
47 if (!TensorShapeUtils::IsScalar(input.shape())) {
48 if (TensorShapeUtils::IsScalar(input_shape)) {
49 input_shape = input.shape();
50 } else {
51 OP_REQUIRES(
52 context, input_shape == input.shape(),
53 errors::InvalidArgument(
54 "Input shapes do not match: ", input_shape.DebugString(),
55 " vs. ", input.shape().DebugString()));
56 }
57 }
58 }
59
60 Tensor* output_tensor = nullptr;
61 OP_REQUIRES_OK(context, context->allocate_output("output", input_shape,
62 &output_tensor));
63 auto output_flat = output_tensor->flat<tstring>();
64
65 std::vector<StringPiece> strings(input_list.size());
66 for (size_t i = 0; i < input_shape.num_elements(); ++i) {
67 for (int j = 0; j < input_list.size(); ++j) {
68 strings[j] = (is_scalar[j]) ? inputs[j](0) : inputs[j](i);
69 }
70 output_flat(i) = absl::StrJoin(strings, separator_);
71 }
72 }
73
74 private:
75 string separator_;
76};
77
78REGISTER_KERNEL_BUILDER(Name("StringJoin").Device(DEVICE_CPU), StringJoinOp);
79
80} // namespace tensorflow
81