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// Copyright 2018-present the CoreDHCP Authors. All rights reserved
// This source code is licensed under the MIT license found in the
// LICENSE file in the root directory of this source tree.
package allocators
import (
"fmt"
"net"
"testing"
"math/rand"
)
func ExampleOffset() {
fmt.Println(Offset(net.ParseIP("2001:db8:0:aabb::"), net.ParseIP("2001:db8:ff::34"), 0))
fmt.Println(Offset(net.ParseIP("2001:db8:0:aabb::"), net.ParseIP("2001:db8:ff::34"), 16))
fmt.Println(Offset(net.ParseIP("2001:db8:0:aabb::"), net.ParseIP("2001:db8:ff::34"), 32))
fmt.Println(Offset(net.ParseIP("2001:db8:0:aabb::"), net.ParseIP("2001:db8:ff::34"), 48))
fmt.Println(Offset(net.ParseIP("2001:db8:0:aabb::"), net.ParseIP("2001:db8:ff::34"), 64))
fmt.Println(Offset(net.ParseIP("2001:db8:0:aabb::"), net.ParseIP("2001:db8:ff::34"), 73))
fmt.Println(Offset(net.ParseIP("2001:db8:0:aabb::"), net.ParseIP("2001:db8:ff::34"), 80))
fmt.Println(Offset(net.ParseIP("2001:db8:0:aabb::"), net.ParseIP("2001:db8:ff::34"), 96))
fmt.Println(Offset(net.ParseIP("2001:db8:0:aabb::"), net.ParseIP("2001:db8:ff::34"), 112))
fmt.Println(Offset(net.ParseIP("2001:db8:0:aabb::"), net.ParseIP("2001:db8:ff::34"), 128))
// Output:
// 0 <nil>
// 0 <nil>
// 0 <nil>
// 254 <nil>
// 16667973 <nil>
// 8534002176 <nil>
// 1092352278528 <nil>
// 71588398925611008 <nil>
// 0 Operation overflows
// 0 Operation overflows
}
func ExampleAddPrefixes() {
fmt.Println(AddPrefixes(net.ParseIP("2001:db8::"), 0xff, 64))
fmt.Println(AddPrefixes(net.ParseIP("2001:db8::"), 0x1, 128))
fmt.Println(AddPrefixes(net.ParseIP("2001:db8::"), 0xff, 32))
fmt.Println(AddPrefixes(net.ParseIP("2001:db8::"), 0x1, 16))
fmt.Println(AddPrefixes(net.ParseIP("2001:db8::"), 0xff, 65))
// Error cases
fmt.Println(AddPrefixes(net.ParseIP("2001:db8::"), 0xff, 8))
fmt.Println(AddPrefixes(net.IP{10, 0, 0, 1}, 64, 32))
// Output:
// 2001:db8:0:ff:: <nil>
// 2001:db8::1 <nil>
// 2001:eb7:: <nil>
// 2002:db8:: <nil>
// 2001:db8:0:7f:8000:: <nil>
// <nil> Operation overflows
// <nil> AddPrefixes needs 128-bit IPs
}
// Offset is used as a hash function, so it needs to be reasonably fast
func BenchmarkOffset(b *testing.B) {
// Need predictable randomness for benchmark reproducibility
rng := rand.New(rand.NewSource(0))
addresses := make([]byte, b.N*net.IPv6len*2)
_, err := rng.Read(addresses)
if err != nil {
b.Fatalf("Could not generate random addresses: %v", err)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
// The arrays will be in cache, so this should amortize to measure mostly just the offset
// computation itself
_, _ = Offset(
addresses[i*2*net.IPv6len:(i*2+1)*net.IPv6len],
addresses[(i*2+1)*net.IPv6len:(i+1)*2*net.IPv6len],
(i*4)%128,
)
}
}
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