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-rw-r--r--absl/strings/cord_analysis.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/absl/strings/cord_analysis.h b/absl/strings/cord_analysis.h
index 7041ad1a..9b9527a5 100644
--- a/absl/strings/cord_analysis.h
+++ b/absl/strings/cord_analysis.h
@@ -31,6 +31,24 @@ namespace cord_internal {
size_t GetEstimatedMemoryUsage(const CordRep* rep);
// Returns the *approximate* number of bytes held in full or in part by this
+// Cord for the distinct memory held by this cord. This is similar to
+// `GetEstimatedMemoryUsage()`, except that if the cord has multiple references
+// to the same memory, that memory is only counted once.
+//
+// For example:
+// absl::Cord cord;
+// cord.append(some_other_cord);
+// cord.append(some_other_cord);
+// // Calls GetEstimatedMemoryUsage() and counts `other_cord` twice:
+// cord.EstimatedMemoryUsage(kTotal);
+// // Calls GetMorePreciseMemoryUsage() and counts `other_cord` once:
+// cord.EstimatedMemoryUsage(kTotalMorePrecise);
+//
+// This is more expensive than `GetEstimatedMemoryUsage()` as it requires
+// deduplicating all memory references.
+size_t GetMorePreciseMemoryUsage(const CordRep* rep);
+
+// Returns the *approximate* number of bytes held in full or in part by this
// CordRep weighted by the sharing ratio of that data. For example, if some data
// edge is shared by 4 different Cords, then each cord is attribute 1/4th of
// the total memory usage as a 'fair share' of the total memory usage.