ml
59 lines
1.4 KiB
Go
59 lines
1.4 KiB
Go
package serial
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import (
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"encoding/binary"
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"errors"
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"io"
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)
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// Decoder is for decoding from a reader.
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type Decoder struct {
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source io.Reader
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firstError error
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offset uint32
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}
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// NewDecoder creates a new Decoder from given source.
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func NewDecoder(source io.Reader) *Decoder {
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return &Decoder{source: source}
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}
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// FirstError returns the error this Decoder encountered the first time.
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func (coder *Decoder) FirstError() error {
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return coder.firstError
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}
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// CurPos returns the current decoding position, in bytes.
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func (coder *Decoder) CurPos() uint32 {
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return coder.offset
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}
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// Code serializes the given value in little endian format using binary.Read().
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func (coder *Decoder) Code(value interface{}) {
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if coder.firstError != nil {
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return
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}
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if codable, isCodable := value.(Codable); isCodable {
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codable.Code(coder)
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} else {
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coder.firstError = binary.Read(coder, binary.LittleEndian, value)
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}
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}
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// Read reads the next bytes from the underlying source.
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func (coder *Decoder) Read(data []byte) (read int, err error) {
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if coder.firstError != nil {
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return 0, coder.firstError
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}
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read, err = coder.source.Read(data)
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coder.offset += uint32(read)
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isErrEOF := errors.Is(err, io.EOF)
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expectedAmountReturned := read == len(data)
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errorCanBeIgnored := isErrEOF && expectedAmountReturned
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if (coder.firstError == nil) && !errorCanBeIgnored {
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coder.firstError = err
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}
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return
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}
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