From a4088d38f32f00062675fa37f396a31ef5427910 Mon Sep 17 00:00:00 2001
From: Nathan VanBenschoten <nvanbenschoten@gmail.com>
Date: Thu, 16 Jun 2022 02:27:46 -0400
Subject: [PATCH] apd: add inline fast-path to BigInt.SetString

Not important, but easy enough to do and makes a difference for the
performance of `Decimal.setString`, which #116 was interested in.
---
 bigint.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/bigint.go b/bigint.go
index c50bb85..6271a40 100644
--- a/bigint.go
+++ b/bigint.go
@@ -886,6 +886,10 @@ func (z *BigInt) SetInt64(x int64) *BigInt {
 
 // SetString calls (big.Int).SetString.
 func (z *BigInt) SetString(s string, base int) (*BigInt, bool) {
+	if i, err := strconv.ParseInt(s, base, 64); err == nil {
+		z.SetInt64(i)
+		return z, true
+	}
 	var tmp1 big.Int //gcassert:noescape
 	zi := z.inner(&tmp1)
 	if _, ok := zi.SetString(s, base); !ok {