From 1bdef34e5463295bf5f77ae0bfd4cb9d10ce3b05 Mon Sep 17 00:00:00 2001
From: yevgenypi <yevgeny.pi@gmail.com>
Date: Thu, 30 Jun 2022 21:03:09 +0200
Subject: [PATCH] small performance improve (#37)

---
 go-bindings/threshold.cpp | 1 +
 go-bindings/utils.cpp     | 2 ++
 go-bindings/utils.hpp     | 1 +
 src/threshold.cpp         | 8 +++-----
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/go-bindings/threshold.cpp b/go-bindings/threshold.cpp
index 17960bcb978e62..834e428c3e9d96 100644
--- a/go-bindings/threshold.cpp
+++ b/go-bindings/threshold.cpp
@@ -24,6 +24,7 @@
 
 std::vector<bls::Bytes> toVectorHashes(void** elems, const size_t len) {
     std::vector<bls::Bytes> vec;
+    vec.reserve(len);
     for (int i = 0 ; i < len; ++i) {
         vec.push_back(
             bls::Bytes((uint8_t*)elems[i], HashSize)
diff --git a/go-bindings/utils.cpp b/go-bindings/utils.cpp
index 0ba85f16dcec08..f7a1ea90beeaba 100644
--- a/go-bindings/utils.cpp
+++ b/go-bindings/utils.cpp
@@ -21,6 +21,7 @@
 template <class T>
 std::vector<T> toBLSVector(void** elems, const size_t len) {
     std::vector<T> vec;
+    vec.reserve(len);
     for (int i = 0 ; i < len; ++i) {
         T* el = (T*)elems[i];
         vec.push_back(*el);
@@ -30,6 +31,7 @@ std::vector<T> toBLSVector(void** elems, const size_t len) {
 
 std::vector<bls::Bytes> toVectorBytes(void** elems, const size_t len, const std::vector<size_t> vecElemsLens) {
     std::vector<bls::Bytes> vec;
+    vec.reserve(len);
     for (int i = 0 ; i < len; ++i) {
         uint8_t* elPtr = (uint8_t*)elems[i];
         vec.push_back(bls::Bytes(elPtr, vecElemsLens[i]));
diff --git a/go-bindings/utils.hpp b/go-bindings/utils.hpp
index d3658caeccc017..0ab817d02f5b45 100644
--- a/go-bindings/utils.hpp
+++ b/go-bindings/utils.hpp
@@ -23,6 +23,7 @@
 template <class T>
 std::vector<T> toBLSVector(void** elems, const size_t len) {
     std::vector<T> vec;
+    vec.reserve(len);
     for (int i = 0 ; i < len; ++i) {
         const T* el = (T*)elems[i];
         vec.push_back(*el);
diff --git a/src/threshold.cpp b/src/threshold.cpp
index 6ed2d5c0ea92e8..5f43ac69f8c655 100644
--- a/src/threshold.cpp
+++ b/src/threshold.cpp
@@ -164,8 +164,7 @@ namespace bls {
     BLSType Poly::Evaluate(const std::vector<BLSType>& vecIn, const Bytes& id) {
         typedef PolyOps<BLSType> Ops;
         Ops ops;
-        std::vector<BLSType> vec = vecIn;
-        if (vec.size() < 2) {
+        if (vecIn.size() < 2) {
             throw std::length_error("At least 2 coefficients required");
         }
 
@@ -174,9 +173,8 @@ namespace bls {
         bn_read_bin(x, id.begin(), Poly::nIdSize);
         ops.ModOrder(x);
 
-        BLSType y = vecIn[vec.size() - 1];
-
-        for (int i = (int) vec.size() - 2; i >= 0; i--) {
+        BLSType y = vecIn.back();
+        for (int i = (int) vecIn.size() - 2; i >= 0; i--) {
             y = ops.Mul(y, x);
             y = ops.Add(y, vecIn[i]);
         }