89 lines
2.0 KiB
Go
89 lines
2.0 KiB
Go
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// Copyright 2017 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package encoding
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import (
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"io"
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"github.com/ProtonMail/go-crypto/openpgp/errors"
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)
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// OID is used to store a variable-length field with a one-octet size
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// prefix. See https://tools.ietf.org/html/rfc6637#section-9.
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type OID struct {
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bytes []byte
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}
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const (
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// maxOID is the maximum number of bytes in a OID.
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maxOID = 254
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// reservedOIDLength1 and reservedOIDLength2 are OID lengths that the RFC
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// specifies are reserved.
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reservedOIDLength1 = 0
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reservedOIDLength2 = 0xff
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)
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// NewOID returns a OID initialized with bytes.
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func NewOID(bytes []byte) *OID {
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switch len(bytes) {
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case reservedOIDLength1, reservedOIDLength2:
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panic("encoding: NewOID argument length is reserved")
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default:
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if len(bytes) > maxOID {
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panic("encoding: NewOID argment too large")
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}
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}
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return &OID{
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bytes: bytes,
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}
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}
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// Bytes returns the decoded data.
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func (o *OID) Bytes() []byte {
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return o.bytes
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}
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// BitLength is the size in bits of the decoded data.
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func (o *OID) BitLength() uint16 {
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return uint16(len(o.bytes) * 8)
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}
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// EncodedBytes returns the encoded data.
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func (o *OID) EncodedBytes() []byte {
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return append([]byte{byte(len(o.bytes))}, o.bytes...)
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}
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// EncodedLength is the size in bytes of the encoded data.
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func (o *OID) EncodedLength() uint16 {
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return uint16(1 + len(o.bytes))
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}
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// ReadFrom reads into b the next OID from r.
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func (o *OID) ReadFrom(r io.Reader) (int64, error) {
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var buf [1]byte
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n, err := io.ReadFull(r, buf[:])
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if err != nil {
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if err == io.EOF {
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err = io.ErrUnexpectedEOF
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}
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return int64(n), err
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}
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switch buf[0] {
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case reservedOIDLength1, reservedOIDLength2:
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return int64(n), errors.UnsupportedError("reserved for future extensions")
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}
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o.bytes = make([]byte, buf[0])
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nn, err := io.ReadFull(r, o.bytes)
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if err == io.EOF {
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err = io.ErrUnexpectedEOF
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}
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return int64(n) + int64(nn), err
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}
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