91 lines
2.8 KiB
Go
91 lines
2.8 KiB
Go
// Copyright (c) Faye Amacker. All rights reserved.
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// Licensed under the MIT License. See LICENSE in the project root for license information.
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package cbor
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import (
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"errors"
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)
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// ByteString represents CBOR byte string (major type 2). ByteString can be used
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// when using a Go []byte is not possible or convenient. For example, Go doesn't
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// allow []byte as map key, so ByteString can be used to support data formats
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// having CBOR map with byte string keys. ByteString can also be used to
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// encode invalid UTF-8 string as CBOR byte string.
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// See DecOption.MapKeyByteStringMode for more details.
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type ByteString string
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// Bytes returns bytes representing ByteString.
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func (bs ByteString) Bytes() []byte {
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return []byte(bs)
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}
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// MarshalCBOR encodes ByteString as CBOR byte string (major type 2).
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func (bs ByteString) MarshalCBOR() ([]byte, error) {
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e := getEncodeBuffer()
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defer putEncodeBuffer(e)
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// Encode length
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encodeHead(e, byte(cborTypeByteString), uint64(len(bs)))
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// Encode data
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buf := make([]byte, e.Len()+len(bs))
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n := copy(buf, e.Bytes())
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copy(buf[n:], bs)
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return buf, nil
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}
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// UnmarshalCBOR decodes CBOR byte string (major type 2) to ByteString.
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// Decoding CBOR null and CBOR undefined sets ByteString to be empty.
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//
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// Deprecated: No longer used by this codec; kept for compatibility
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// with user apps that directly call this function.
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func (bs *ByteString) UnmarshalCBOR(data []byte) error {
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if bs == nil {
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return errors.New("cbor.ByteString: UnmarshalCBOR on nil pointer")
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}
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d := decoder{data: data, dm: defaultDecMode}
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// Check well-formedness of CBOR data item.
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// ByteString.UnmarshalCBOR() is exported, so
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// the codec needs to support same behavior for:
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// - Unmarshal(data, *ByteString)
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// - ByteString.UnmarshalCBOR(data)
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err := d.wellformed(false, false)
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if err != nil {
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return err
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}
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return bs.unmarshalCBOR(data)
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}
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// unmarshalCBOR decodes CBOR byte string (major type 2) to ByteString.
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// Decoding CBOR null and CBOR undefined sets ByteString to be empty.
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// This function assumes data is well-formed, and does not perform bounds checking.
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// This function is called by Unmarshal().
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func (bs *ByteString) unmarshalCBOR(data []byte) error {
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if bs == nil {
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return errors.New("cbor.ByteString: UnmarshalCBOR on nil pointer")
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}
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// Decoding CBOR null and CBOR undefined to ByteString resets data.
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// This behavior is similar to decoding CBOR null and CBOR undefined to []byte.
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if len(data) == 1 && (data[0] == 0xf6 || data[0] == 0xf7) {
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*bs = ""
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return nil
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}
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d := decoder{data: data, dm: defaultDecMode}
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// Check if CBOR data type is byte string
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if typ := d.nextCBORType(); typ != cborTypeByteString {
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return &UnmarshalTypeError{CBORType: typ.String(), GoType: typeByteString.String()}
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}
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b, _ := d.parseByteString()
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*bs = ByteString(b)
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return nil
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}
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