Add RegexReplace Op that internally calls RE2::Replace.

PiperOrigin-RevId: 187467840

1 files changed, 76 insertions, 0 deletions

diff --git a/tensorflow/core/kernels/regex_replace_op.cc b/tensorflow/core/kernels/regex_replace_op.cc
new file mode 100644
index 0000000000..59ec854a79
--- /dev/null
+++ b/tensorflow/core/kernels/regex_replace_op.cc
@@ -0,0 +1,76 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#include <string>
+
+#include "re2/re2.h"
+#include "tensorflow/core/framework/op_kernel.h"
+#include "tensorflow/core/framework/tensor.h"
+#include "tensorflow/core/lib/core/errors.h"
+#include "tensorflow/core/lib/core/status.h"
+
+namespace tensorflow {
+
+class RegexReplaceOp : public OpKernel {
+ public:
+  explicit RegexReplaceOp(OpKernelConstruction* ctx) : OpKernel(ctx) {
+    OP_REQUIRES_OK(ctx, ctx->GetAttr("replace_global", &replace_global_));
+  }
+
+  void Compute(OpKernelContext* ctx) override {
+    const Tensor* input_tensor;
+    OP_REQUIRES_OK(ctx, ctx->input("input", &input_tensor));
+    const auto& input_flat = input_tensor->flat<string>();
+
+    const Tensor* pattern_tensor;
+    OP_REQUIRES_OK(ctx, ctx->input("pattern", &pattern_tensor));
+    OP_REQUIRES(ctx, TensorShapeUtils::IsScalar(pattern_tensor->shape()),
+                errors::InvalidArgument("Pattern must be scalar, but received ",
+                                        pattern_tensor->shape().DebugString()));
+    const string pattern = pattern_tensor->flat<string>()(0);
+    const RE2 match(pattern);
+    OP_REQUIRES(ctx, match.ok(),
+                errors::InvalidArgument("Invalid pattern: ", pattern,
+                                        ", error: ", match.error()));
+
+    const Tensor* rewrite_tensor;
+    OP_REQUIRES_OK(ctx, ctx->input("rewrite", &rewrite_tensor));
+    OP_REQUIRES(ctx, TensorShapeUtils::IsScalar(rewrite_tensor->shape()),
+                errors::InvalidArgument("Rewrite must be scalar, but received ",
+                                        rewrite_tensor->shape().DebugString()));
+    const string rewrite = rewrite_tensor->flat<string>()(0);
+
+    Tensor* output_tensor = nullptr;
+    OP_REQUIRES_OK(ctx, ctx->allocate_output("output", input_tensor->shape(),
+                                             &output_tensor));
+    auto output_flat = output_tensor->flat<string>();
+    for (size_t i = 0; i < input_flat.size(); ++i) {
+      output_flat(i) = input_flat(i);
+      if (replace_global_) {
+        RE2::GlobalReplace(&output_flat(i), match, rewrite);
+      } else {
+        RE2::Replace(&output_flat(i), match, rewrite);
+      }
+    }
+  }
+
+ private:
+  bool replace_global_;
+};
+
+REGISTER_KERNEL_BUILDER(Name("RegexReplace").Device(DEVICE_CPU),
+                        RegexReplaceOp);
+
+}  // namespace tensorflow