1 files changed, 42 insertions, 0 deletions
diff --git a/tools/finditer/finditer.go b/tools/finditer/finditer.go
new file mode 100644
index 0000000..e788d89
--- /dev/null
+++ b/tools/finditer/finditer.go
@@ -0,0 +1,42 @@
+package main
+
+import (
+	"encoding/hex"
+	"fmt"
+	"sort"
+	"testing"
+	"time"
+
+	"roseh.moe/cmd/roseh.moe/internal/pwhash"
+)
+
+func mustHex(s string) []byte {
+	b, err := hex.DecodeString(s)
+	if err != nil {
+		panic(err)
+	}
+	return b
+}
+
+var salt = mustHex("34539b5dd2591415")
+
+func benchmarkHashIter(iter int) time.Duration {
+	const password = "wavy upend 4z jk linda k zing four atop pi"
+	return time.Duration(testing.Benchmark(func(b *testing.B) {
+		for b.Loop() {
+			pwhash.HashIter(password, salt, iter)
+		}
+	}).NsPerOp())
+}
+
+func main() {
+	const targetTime = 5 * time.Second
+	iter := 8192
+	for ; benchmarkHashIter(iter) < targetTime; iter *= 2 {
+	}
+	lo := iter / 2
+	hi := iter
+	fmt.Println(lo + sort.Search(hi-lo, func(n int) bool {
+		return benchmarkHashIter(lo+n) > targetTime
+	}))
+}