From 810691809711abd05ff5fb3a7d974f7981c5ec86 Mon Sep 17 00:00:00 2001
From: Ethan Frey <ethanfrey@users.noreply.github.com>
Date: Tue, 2 Jan 2018 18:10:20 +0100
Subject: [PATCH] Add benchmarks for hash functions

---
 benchmarks/hash_test.go | 47 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 benchmarks/hash_test.go

diff --git a/benchmarks/hash_test.go b/benchmarks/hash_test.go
new file mode 100644
index 000000000..83491a9f7
--- /dev/null
+++ b/benchmarks/hash_test.go
@@ -0,0 +1,47 @@
+package benchmarks
+
+import (
+	"crypto"
+	"fmt"
+	"hash"
+	"testing"
+
+	_ "crypto/sha256"
+
+	_ "golang.org/x/crypto/ripemd160"
+	_ "golang.org/x/crypto/sha3"
+)
+
+func BenchmarkHash(b *testing.B) {
+	hashers := []struct {
+		name   string
+		size   int
+		hasher hash.Hash
+	}{
+		{"ripemd160", 64, crypto.RIPEMD160.New()},
+		{"ripemd160", 512, crypto.RIPEMD160.New()},
+		{"sha2-256", 64, crypto.SHA256.New()},
+		{"sha2-256", 512, crypto.SHA256.New()},
+		{"sha3-256", 64, crypto.SHA3_256.New()},
+		{"sha3-256", 512, crypto.SHA3_256.New()},
+	}
+
+	for _, h := range hashers {
+		prefix := fmt.Sprintf("%s-%d", h.name, h.size)
+		b.Run(prefix, func(sub *testing.B) {
+			benchHasher(sub, h.hasher, h.size)
+		})
+	}
+}
+
+func benchHasher(b *testing.B, hasher hash.Hash, size int) {
+	// create all random bytes before to avoid timing this
+	inputs := randBytes(b.N + size + 1)
+
+	for i := 0; i < b.N; i++ {
+		hasher.Reset()
+		// grab a slice of size bytes from random string
+		hasher.Write(inputs[i : i+size])
+		hasher.Sum(nil)
+	}
+}