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// Copyright (C) 2019-2024 Algorand, Inc.
// This file is part of go-algorand
//
// go-algorand is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// go-algorand is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with go-algorand. If not, see <https://www.gnu.org/licenses/>.
package basics
import (
"math"
"math/big"
"testing"
"github.com/algorand/go-algorand/test/partitiontest"
"github.com/stretchr/testify/require"
)
func TestSubSaturate(t *testing.T) {
partitiontest.PartitionTest(t)
t.Parallel()
a := Round(1)
b := Round(2)
require.Equal(t, a.SubSaturate(b), Round(0))
require.Equal(t, a.SubSaturate(a), Round(0))
require.Equal(t, b.SubSaturate(a), Round(1))
}
func TestSubSaturate32(t *testing.T) {
partitiontest.PartitionTest(t)
t.Parallel()
require.Equal(t, uint32(0), SubSaturate(uint32(0), uint32(1)))
require.Equal(t, uint32(0), SubSaturate(uint32(1), uint32(2)))
require.Equal(t, uint32(0), SubSaturate(uint32(1), uint32(1)))
require.Equal(t, uint32(0), SubSaturate(uint32(1), math.MaxUint32))
require.Equal(t, uint32(1), SubSaturate(uint32(2), uint32(1)))
require.Equal(t, uint32(math.MaxUint32-1), SubSaturate(math.MaxUint32, uint32(1)))
}
func TestAddSaturate32(t *testing.T) {
partitiontest.PartitionTest(t)
t.Parallel()
require.Equal(t, uint32(1), AddSaturate(uint32(0), uint32(1)))
require.Equal(t, uint32(math.MaxUint32-1), AddSaturate(math.MaxUint32-2, uint32(1)))
require.Equal(t, uint32(math.MaxUint32), AddSaturate(math.MaxUint32, uint32(0)))
require.Equal(t, uint32(math.MaxUint32), AddSaturate(math.MaxUint32-1, uint32(1)))
require.Equal(t, uint32(math.MaxUint32), AddSaturate(math.MaxUint32, uint32(2)))
}
func BenchmarkAddSaturateGenerics(b *testing.B) {
startVar := uint64(0xdeadbeef)
for n := uint64(0); n < uint64(b.N); n++ {
temp := AddSaturate(n, startVar)
startVar = temp
}
}
// oldOAdd adds 2 values with overflow detection
func oldOAdd(a uint64, b uint64) (res uint64, overflowed bool) {
res = a + b
overflowed = res < a
return
}
// addSaturateU64Old adds 2 values with saturation on overflow (OLD IMPLEMENTATION)
func addSaturateU64Old(a uint64, b uint64) uint64 {
res, overflowed := oldOAdd(a, b)
if overflowed {
return math.MaxUint64
}
return res
}
func BenchmarkAddSaturateU64Old(b *testing.B) {
startVar := uint64(0xdeadbeef)
for n := uint64(0); n < uint64(b.N); n++ {
temp := addSaturateU64Old(n, startVar)
startVar = temp
}
}
func BenchmarkSubSaturateGenerics(b *testing.B) {
startVar := uint64(0xdeadbeef)
for n := uint64(0); n < uint64(b.N); n++ {
temp := SubSaturate(n, startVar)
startVar = temp
}
}
// oldOSub subtracts b from a with overflow detection
func oldOSub(a uint64, b uint64) (res uint64, overflowed bool) {
res = a - b
overflowed = res > a
return
}
// subSaturateU64Old subtracts 2 values with saturation on underflow (OLD IMPLEMENTATION)
func subSaturateU64Old(a uint64, b uint64) uint64 {
res, overflowed := oldOSub(a, b)
if overflowed {
return 0
}
return res
}
func BenchmarkSubSaturateU64Old(b *testing.B) {
startVar := uint64(0xdeadbeef)
for n := uint64(0); n < uint64(b.N); n++ {
temp := subSaturateU64Old(n, startVar)
startVar = temp
}
}
func BenchmarkMulSaturateGenerics(b *testing.B) {
startVar := uint64(0xdeadbeef)
for n := uint64(1); n <= uint64(b.N); n++ {
temp := MulSaturate(n, startVar)
startVar = temp
}
}
// oldOMul multiplies 2 values with overflow detection
func oldOMul(a uint64, b uint64) (res uint64, overflowed bool) {
if b == 0 {
return 0, false
}
c := a * b
if c/b != a {
return 0, true
}
return c, false
}
// mulSaturateU64Old multiplies 2 values with saturation on overflow (OLD IMPLEMENTATION)
func mulSaturateU64Old(a uint64, b uint64) uint64 {
res, overflowed := oldOMul(a, b)
if overflowed {
return math.MaxUint64
}
return res
}
func BenchmarkMulSaturateU64Old(b *testing.B) {
startVar := uint64(0xdeadbeef)
for n := uint64(1); n <= uint64(b.N); n++ {
temp := mulSaturateU64Old(n, startVar)
startVar = temp
}
}
func TestRoundUpToMultipleOf(t *testing.T) {
partitiontest.PartitionTest(t)
t.Parallel()
r := Round(24)
for n := Round(1); n < Round(100); n++ {
nextMul := r.RoundUpToMultipleOf(n)
require.True(t, r <= nextMul)
require.Equal(t, nextMul%n, Round(0))
if n < r {
prevMul := nextMul - n
require.True(t, prevMul < r)
}
}
}
func TestRoundDownToMultipleOf(t *testing.T) {
partitiontest.PartitionTest(t)
t.Parallel()
a := require.New(t)
r := Round(24)
for n := Round(1); n < Round(100); n++ {
mul := r.RoundDownToMultipleOf(n)
a.True(mul <= r)
a.Equal(Round(0), mul%n)
if r < n {
a.Equal(Round(0), mul)
} else if r == n {
a.Equal(n, mul)
}
}
}
func OldMuldiv(a uint64, b uint64, c uint64) (res uint64, overflow bool) {
var aa big.Int
aa.SetUint64(a)
var bb big.Int
bb.SetUint64(b)
var cc big.Int
cc.SetUint64(c)
aa.Mul(&aa, &bb)
aa.Div(&aa, &cc)
return aa.Uint64(), !aa.IsUint64()
}
func BenchmarkOldMuldiv(b *testing.B) {
for i := 0; i < b.N; i++ {
u64 := uint64(i + 1)
OldMuldiv(u64, u64, u64)
OldMuldiv(math.MaxUint64, u64, u64)
OldMuldiv(u64, math.MaxUint64, u64)
OldMuldiv(math.MaxInt64, math.MaxInt64, u64)
}
}
func BenchmarkNewMuldiv(b *testing.B) {
for i := 0; i < b.N; i++ {
u64 := uint64(i + 1)
Muldiv(u64, u64, u64)
Muldiv(math.MaxUint64, u64, u64)
Muldiv(u64, math.MaxUint64, u64)
Muldiv(math.MaxInt64, math.MaxInt64, u64)
}
}
func TestNewMuldiv(t *testing.T) {
partitiontest.PartitionTest(t)
t.Parallel()
test := func(a, b, c uint64) {
r1, o1 := OldMuldiv(a, b, c)
r2, o2 := Muldiv(a, b, c)
require.Equal(t, o1, o2)
// implementations differ in r1,r2 if overflow. old implemention is
// returning an unspecified value
if !o1 {
require.Equal(t, r1, r2)
}
}
test(1, 2, 3)
test(1000000000, 2000000000, 1)
test(math.MaxUint64, 3, 4)
test(math.MaxUint64, 4, 3)
test(3, math.MaxUint64, 4)
test(4, math.MaxUint64, 3)
test(math.MaxUint64, math.MaxUint64, math.MaxUint64)
test(math.MaxUint64, math.MaxUint64, 5)
}
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