Add `absl::AppendCordToString`

PiperOrigin-RevId: 626039936
Change-Id: I6e791363bab06d66029a8565c42d158a2fe176f0

1 files changed, 23 insertions, 0 deletions

diff --git a/absl/strings/cord.h b/absl/strings/cord.h
index c9f6767b..95519cd3 100644
--- a/absl/strings/cord.h
+++ b/absl/strings/cord.h
@@ -105,6 +105,7 @@ class CordTestPeer;
 template <typename Releaser>
 Cord MakeCordFromExternal(absl::string_view, Releaser&&);
 void CopyCordToString(const Cord& src, absl::Nonnull<std::string*> dst);
+void AppendCordToString(const Cord& src, absl::Nonnull<std::string*> dst);
 
 // Cord memory accounting modes
 enum class CordMemoryAccounting {
@@ -421,6 +422,18 @@ class Cord {
   friend void CopyCordToString(const Cord& src,
                                absl::Nonnull<std::string*> dst);
 
+  // AppendCordToString()
+  //
+  // Appends the contents of a `src` Cord to a `*dst` string.
+  //
+  // This function optimizes the case of appending to a non-empty destination
+  // string. If `*dst` already has capacity to store the contents of the cord,
+  // this function does not invalidate pointers previously returned by
+  // `dst->data()`. If `*dst` is a new object, prefer to simply use the
+  // conversion operator to `std::string`.
+  friend void AppendCordToString(const Cord& src,
+                                 absl::Nonnull<std::string*> dst);
+
   class CharIterator;
 
   //----------------------------------------------------------------------------
@@ -1066,6 +1079,8 @@ class Cord {
       const;
 
   CharIterator FindImpl(CharIterator it, absl::string_view needle) const;
+
+  void CopyToArrayImpl(absl::Nonnull<char*> dst) const;
 };
 
 ABSL_NAMESPACE_END
@@ -1450,6 +1465,14 @@ inline bool Cord::StartsWith(absl::string_view rhs) const {
   return EqualsImpl(rhs, rhs_size);
 }
 
+inline void Cord::CopyToArrayImpl(absl::Nonnull<char*> dst) const {
+  if (!contents_.is_tree()) {
+    if (!empty()) contents_.CopyToArray(dst);
+  } else {
+    CopyToArraySlowPath(dst);
+  }
+}
+
 inline void Cord::ChunkIterator::InitTree(
     absl::Nonnull<cord_internal::CordRep*> tree) {
   tree = cord_internal::SkipCrcNode(tree);