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diff --git a/absl/strings/internal/cord_rep_crc.h b/absl/strings/internal/cord_rep_crc.h
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+// Copyright 2021 The Abseil Authors
+//
+// 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
+//
+//     https://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.
+
+#ifndef ABSL_STRINGS_INTERNAL_CORD_REP_CRC_H_
+#define ABSL_STRINGS_INTERNAL_CORD_REP_CRC_H_
+
+#include <cassert>
+#include <cstdint>
+
+#include "absl/base/config.h"
+#include "absl/base/optimization.h"
+#include "absl/strings/internal/cord_internal.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace cord_internal {
+
+// CordRepCrc is a CordRep node intended only to appear at the top level of a
+// cord tree.  It associates an "expected CRC" with the contained data, to allow
+// for easy passage of checksum data in Cord data flows.
+//
+// From Cord's perspective, the crc value has no semantics; any validation of
+// the contained checksum is the user's responsibility.
+struct CordRepCrc : public CordRep {
+  CordRep* child;
+  uint32_t crc;
+
+  // Consumes `child` and returns a CordRepCrc prefixed tree containing `child`.
+  // If the specified `child` is itself a CordRepCrc node, then this method
+  // either replaces the existing node, or directly updates the crc value in it
+  // depending on the node being shared or not, i.e.: refcount.IsOne().
+  // `child` must not be null. Never returns null.
+  static CordRepCrc* New(CordRep* child, uint32_t crc);
+
+  // Destroys (deletes) the provided node. `node` must not be null.
+  static void Destroy(CordRepCrc* node);
+};
+
+// Consumes `rep` and returns a CordRep* with any outer CordRepCrc wrapper
+// removed.  This is usually a no-op (returning `rep`), but this will remove and
+// unref an outer CordRepCrc node.
+inline CordRep* RemoveCrcNode(CordRep* rep) {
+  assert(rep != nullptr);
+  if (ABSL_PREDICT_FALSE(rep->IsCrc())) {
+    CordRep* child = rep->crc()->child;
+    if (rep->refcount.IsOne()) {
+      delete rep->crc();
+    } else {
+      CordRep::Ref(child);
+      CordRep::Unref(rep);
+    }
+    return child;
+  }
+  return rep;
+}
+
+// Returns `rep` if it is not a CordRepCrc node, or its child if it is.
+// Does not consume or create a reference on `rep` or the returned value.
+inline CordRep* SkipCrcNode(CordRep* rep) {
+  assert(rep != nullptr);
+  if (ABSL_PREDICT_FALSE(rep->IsCrc())) {
+    return rep->crc()->child;
+  } else {
+    return rep;
+  }
+}
+
+inline const CordRep* SkipCrcNode(const CordRep* rep) {
+  assert(rep != nullptr);
+  if (ABSL_PREDICT_FALSE(rep->IsCrc())) {
+    return rep->crc()->child;
+  } else {
+    return rep;
+  }
+}
+
+inline CordRepCrc* CordRep::crc() {
+  assert(IsCrc());
+  return static_cast<CordRepCrc*>(this);
+}
+
+inline const CordRepCrc* CordRep::crc() const {
+  assert(IsCrc());
+  return static_cast<const CordRepCrc*>(this);
+}
+
+}  // namespace cord_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_STRINGS_INTERNAL_CORD_REP_CRC_H_