From d683492b002511bd068600dae29a6e57d58c7194 Mon Sep 17 00:00:00 2001
From: Conner Fromknecht <conner@lightning.engineering>
Date: Thu, 4 Feb 2021 23:45:31 -0800
Subject: [PATCH] txscript: Add benchmark for CalcWitnessSigHash

---
 txscript/bench_test.go | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/txscript/bench_test.go b/txscript/bench_test.go
index b129b80386..037ce531f7 100644
--- a/txscript/bench_test.go
+++ b/txscript/bench_test.go
@@ -50,3 +50,23 @@ func BenchmarkCalcSigHash(b *testing.B) {
 		}
 	}
 }
+
+// BenchmarkCalcWitnessSigHash benchmarks how long it takes to calculate the
+// witness signature hashes for all inputs of a transaction with many inputs.
+func BenchmarkCalcWitnessSigHash(b *testing.B) {
+	sigHashes := NewTxSigHashes(&manyInputsBenchTx)
+
+	b.ResetTimer()
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		for j := 0; j < len(manyInputsBenchTx.TxIn); j++ {
+			_, err := CalcWitnessSigHash(
+				prevOutScript, sigHashes, SigHashAll,
+				&manyInputsBenchTx, j, 5,
+			)
+			if err != nil {
+				b.Fatalf("failed to calc signature hash: %v", err)
+			}
+		}
+	}
+}