78 lines
2 KiB
Go
78 lines
2 KiB
Go
// Licensed to Elasticsearch B.V. under one or more contributor
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// license agreements. See the NOTICE file distributed with
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// this work for additional information regarding copyright
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// ownership. Elasticsearch B.V. licenses this file to you under
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// the Apache License, Version 2.0 (the "License"); you may
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// not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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package common
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import (
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"bytes"
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"crypto/rand"
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"errors"
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"fmt"
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)
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// Byte order utilities
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func BytesNtohs(b []byte) uint16 {
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return uint16(b[0])<<8 | uint16(b[1])
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}
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func BytesNtohl(b []byte) uint32 {
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return uint32(b[0])<<24 | uint32(b[1])<<16 |
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uint32(b[2])<<8 | uint32(b[3])
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}
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func BytesHtohl(b []byte) uint32 {
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return uint32(b[3])<<24 | uint32(b[2])<<16 |
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uint32(b[1])<<8 | uint32(b[0])
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}
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func BytesNtohll(b []byte) uint64 {
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return uint64(b[0])<<56 | uint64(b[1])<<48 |
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uint64(b[2])<<40 | uint64(b[3])<<32 |
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uint64(b[4])<<24 | uint64(b[5])<<16 |
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uint64(b[6])<<8 | uint64(b[7])
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}
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// Ipv4_Ntoa transforms an IP4 address in it's dotted notation
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func IPv4Ntoa(ip uint32) string {
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return fmt.Sprintf("%d.%d.%d.%d",
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byte(ip>>24), byte(ip>>16),
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byte(ip>>8), byte(ip))
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}
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// ReadString extracts the first null terminated string from
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// a slice of bytes.
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func ReadString(s []byte) (string, error) {
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i := bytes.IndexByte(s, 0)
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if i < 0 {
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return "", errors.New("No string found")
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}
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res := string(s[:i])
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return res, nil
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}
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// RandomBytes return a slice of random bytes of the defined length
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func RandomBytes(length int) ([]byte, error) {
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r := make([]byte, length)
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_, err := rand.Read(r)
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if err != nil {
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return nil, err
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}
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return r, nil
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}
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