84 lines
1.9 KiB
Go
84 lines
1.9 KiB
Go
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package uuid
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import (
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"crypto/rand"
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"encoding/hex"
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"fmt"
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"io"
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)
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// GenerateRandomBytes is used to generate random bytes of given size.
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func GenerateRandomBytes(size int) ([]byte, error) {
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return GenerateRandomBytesWithReader(size, rand.Reader)
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}
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// GenerateRandomBytesWithReader is used to generate random bytes of given size read from a given reader.
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func GenerateRandomBytesWithReader(size int, reader io.Reader) ([]byte, error) {
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if reader == nil {
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return nil, fmt.Errorf("provided reader is nil")
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}
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buf := make([]byte, size)
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if _, err := io.ReadFull(reader, buf); err != nil {
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return nil, fmt.Errorf("failed to read random bytes: %v", err)
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}
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return buf, nil
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}
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const uuidLen = 16
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// GenerateUUID is used to generate a random UUID
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func GenerateUUID() (string, error) {
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return GenerateUUIDWithReader(rand.Reader)
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}
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// GenerateUUIDWithReader is used to generate a random UUID with a given Reader
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func GenerateUUIDWithReader(reader io.Reader) (string, error) {
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if reader == nil {
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return "", fmt.Errorf("provided reader is nil")
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}
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buf, err := GenerateRandomBytesWithReader(uuidLen, reader)
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if err != nil {
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return "", err
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}
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return FormatUUID(buf)
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}
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func FormatUUID(buf []byte) (string, error) {
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if buflen := len(buf); buflen != uuidLen {
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return "", fmt.Errorf("wrong length byte slice (%d)", buflen)
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}
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return fmt.Sprintf("%x-%x-%x-%x-%x",
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buf[0:4],
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buf[4:6],
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buf[6:8],
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buf[8:10],
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buf[10:16]), nil
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}
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func ParseUUID(uuid string) ([]byte, error) {
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if len(uuid) != 2 * uuidLen + 4 {
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return nil, fmt.Errorf("uuid string is wrong length")
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}
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if uuid[8] != '-' ||
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uuid[13] != '-' ||
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uuid[18] != '-' ||
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uuid[23] != '-' {
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return nil, fmt.Errorf("uuid is improperly formatted")
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}
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hexStr := uuid[0:8] + uuid[9:13] + uuid[14:18] + uuid[19:23] + uuid[24:36]
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ret, err := hex.DecodeString(hexStr)
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if err != nil {
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return nil, err
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}
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if len(ret) != uuidLen {
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return nil, fmt.Errorf("decoded hex is the wrong length")
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}
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return ret, nil
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}
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