forked from cerc-io/plugeth
5f7826270c
* common/math: optimize PaddedBigBytes, use it more
name old time/op new time/op delta
PaddedBigBytes-8 71.1ns ± 5% 46.1ns ± 1% -35.15% (p=0.000 n=20+19)
name old alloc/op new alloc/op delta
PaddedBigBytes-8 48.0B ± 0% 32.0B ± 0% -33.33% (p=0.000 n=20+20)
* all: unify big.Int zero checks
Various checks were in use. This commit replaces them all with Int.Sign,
which is cheaper and less code.
eg templates:
func before(x *big.Int) bool { return x.BitLen() == 0 }
func after(x *big.Int) bool { return x.Sign() == 0 }
func before(x *big.Int) bool { return x.BitLen() > 0 }
func after(x *big.Int) bool { return x.Sign() != 0 }
func before(x *big.Int) int { return x.Cmp(common.Big0) }
func after(x *big.Int) int { return x.Sign() }
* common/math, crypto/secp256k1: make ReadBits public in package math
220 lines
6.3 KiB
Go
220 lines
6.3 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package math
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import (
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"bytes"
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"encoding/hex"
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"math/big"
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"testing"
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)
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func TestParseBig256(t *testing.T) {
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tests := []struct {
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input string
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num *big.Int
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ok bool
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}{
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{"", big.NewInt(0), true},
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{"0", big.NewInt(0), true},
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{"0x0", big.NewInt(0), true},
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{"12345678", big.NewInt(12345678), true},
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{"0x12345678", big.NewInt(0x12345678), true},
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{"0X12345678", big.NewInt(0x12345678), true},
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// Tests for leading zero behaviour:
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{"0123456789", big.NewInt(123456789), true}, // note: not octal
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{"00", big.NewInt(0), true},
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{"0x00", big.NewInt(0), true},
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{"0x012345678abc", big.NewInt(0x12345678abc), true},
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// Invalid syntax:
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{"abcdef", nil, false},
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{"0xgg", nil, false},
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// Larger than 256 bits:
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{"115792089237316195423570985008687907853269984665640564039457584007913129639936", nil, false},
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}
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for _, test := range tests {
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num, ok := ParseBig256(test.input)
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if ok != test.ok {
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t.Errorf("ParseBig(%q) -> ok = %t, want %t", test.input, ok, test.ok)
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continue
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}
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if num != nil && test.num != nil && num.Cmp(test.num) != 0 {
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t.Errorf("ParseBig(%q) -> %d, want %d", test.input, num, test.num)
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}
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}
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}
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func TestMustParseBig256(t *testing.T) {
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defer func() {
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if recover() == nil {
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t.Error("MustParseBig should've panicked")
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}
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}()
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MustParseBig256("ggg")
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}
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func TestBigMax(t *testing.T) {
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a := big.NewInt(10)
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b := big.NewInt(5)
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max1 := BigMax(a, b)
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if max1 != a {
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t.Errorf("Expected %d got %d", a, max1)
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}
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max2 := BigMax(b, a)
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if max2 != a {
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t.Errorf("Expected %d got %d", a, max2)
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}
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}
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func TestBigMin(t *testing.T) {
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a := big.NewInt(10)
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b := big.NewInt(5)
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min1 := BigMin(a, b)
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if min1 != b {
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t.Errorf("Expected %d got %d", b, min1)
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}
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min2 := BigMin(b, a)
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if min2 != b {
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t.Errorf("Expected %d got %d", b, min2)
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}
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}
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func TestFirstBigSet(t *testing.T) {
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tests := []struct {
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num *big.Int
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ix int
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}{
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{big.NewInt(0), 0},
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{big.NewInt(1), 0},
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{big.NewInt(2), 1},
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{big.NewInt(0x100), 8},
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}
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for _, test := range tests {
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if ix := FirstBitSet(test.num); ix != test.ix {
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t.Errorf("FirstBitSet(b%b) = %d, want %d", test.num, ix, test.ix)
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}
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}
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}
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func TestPaddedBigBytes(t *testing.T) {
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tests := []struct {
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num *big.Int
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n int
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result []byte
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}{
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{num: big.NewInt(0), n: 4, result: []byte{0, 0, 0, 0}},
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{num: big.NewInt(1), n: 4, result: []byte{0, 0, 0, 1}},
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{num: big.NewInt(512), n: 4, result: []byte{0, 0, 2, 0}},
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{num: BigPow(2, 32), n: 4, result: []byte{1, 0, 0, 0, 0}},
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}
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for _, test := range tests {
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if result := PaddedBigBytes(test.num, test.n); !bytes.Equal(result, test.result) {
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t.Errorf("PaddedBigBytes(%d, %d) = %v, want %v", test.num, test.n, result, test.result)
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}
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}
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}
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func BenchmarkPaddedBigBytes(b *testing.B) {
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bigint := MustParseBig256("123456789123456789123456789123456789")
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for i := 0; i < b.N; i++ {
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PaddedBigBytes(bigint, 32)
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}
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}
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func TestReadBits(t *testing.T) {
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check := func(input string) {
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want, _ := hex.DecodeString(input)
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int, _ := new(big.Int).SetString(input, 16)
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buf := make([]byte, len(want))
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ReadBits(int, buf)
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if !bytes.Equal(buf, want) {
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t.Errorf("have: %x\nwant: %x", buf, want)
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}
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}
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check("000000000000000000000000000000000000000000000000000000FEFCF3F8F0")
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check("0000000000012345000000000000000000000000000000000000FEFCF3F8F0")
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check("18F8F8F1000111000110011100222004330052300000000000000000FEFCF3F8F0")
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}
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func TestU256(t *testing.T) {
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tests := []struct{ x, y *big.Int }{
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{x: big.NewInt(0), y: big.NewInt(0)},
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{x: big.NewInt(1), y: big.NewInt(1)},
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{x: BigPow(2, 255), y: BigPow(2, 255)},
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{x: BigPow(2, 256), y: big.NewInt(0)},
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{x: new(big.Int).Add(BigPow(2, 256), big.NewInt(1)), y: big.NewInt(1)},
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// negative values
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{x: big.NewInt(-1), y: new(big.Int).Sub(BigPow(2, 256), big.NewInt(1))},
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{x: big.NewInt(-2), y: new(big.Int).Sub(BigPow(2, 256), big.NewInt(2))},
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{x: BigPow(2, -255), y: big.NewInt(1)},
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}
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for _, test := range tests {
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if y := U256(new(big.Int).Set(test.x)); y.Cmp(test.y) != 0 {
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t.Errorf("U256(%x) = %x, want %x", test.x, y, test.y)
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}
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}
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}
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func TestS256(t *testing.T) {
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tests := []struct{ x, y *big.Int }{
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{x: big.NewInt(0), y: big.NewInt(0)},
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{x: big.NewInt(1), y: big.NewInt(1)},
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{x: big.NewInt(2), y: big.NewInt(2)},
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{
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x: new(big.Int).Sub(BigPow(2, 255), big.NewInt(1)),
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y: new(big.Int).Sub(BigPow(2, 255), big.NewInt(1)),
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},
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{
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x: BigPow(2, 255),
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y: new(big.Int).Neg(BigPow(2, 255)),
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},
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{
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x: new(big.Int).Sub(BigPow(2, 256), big.NewInt(1)),
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y: big.NewInt(-1),
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},
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{
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x: new(big.Int).Sub(BigPow(2, 256), big.NewInt(2)),
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y: big.NewInt(-2),
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},
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}
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for _, test := range tests {
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if y := S256(test.x); y.Cmp(test.y) != 0 {
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t.Errorf("S256(%x) = %x, want %x", test.x, y, test.y)
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}
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}
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}
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func TestExp(t *testing.T) {
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tests := []struct{ base, exponent, result *big.Int }{
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{base: big.NewInt(0), exponent: big.NewInt(0), result: big.NewInt(1)},
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{base: big.NewInt(1), exponent: big.NewInt(0), result: big.NewInt(1)},
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{base: big.NewInt(1), exponent: big.NewInt(1), result: big.NewInt(1)},
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{base: big.NewInt(1), exponent: big.NewInt(2), result: big.NewInt(1)},
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{base: big.NewInt(3), exponent: big.NewInt(144), result: MustParseBig256("507528786056415600719754159741696356908742250191663887263627442114881")},
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{base: big.NewInt(2), exponent: big.NewInt(255), result: MustParseBig256("57896044618658097711785492504343953926634992332820282019728792003956564819968")},
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}
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for _, test := range tests {
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if result := Exp(test.base, test.exponent); result.Cmp(test.result) != 0 {
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t.Errorf("Exp(%d, %d) = %d, want %d", test.base, test.exponent, result, test.result)
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}
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}
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}
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