gnark/io/bytes.go at master · devlongs/gnark

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package io

import (

"encoding/binary"

"fmt"

"io"

"math"

)

// WriteBytesShort writes a short byte slice (maximum length of 255) to a writer.

func WriteBytesShort(challenge []byte, writer io.Writer) (int64, error) {

if len(challenge) > 255 {

return 0, fmt.Errorf("challenge too long %d > 255", len(challenge))

}

if err := binary.Write(writer, binary.BigEndian, uint8(len(challenge))); err != nil {

return math.MinInt, err // in this case we're not sure how many bytes were written

}

n, err := writer.Write(challenge)

return int64(n) + 1, err

}

// ReadBytesShort reads a short byte slice (maximum length of 255) from a reader.

func ReadBytesShort(reader io.Reader) ([]byte, int64, error) {

var length uint8

if err := binary.Read(reader, binary.BigEndian, &length); err != nil {

return nil, math.MinInt, err // in this case we're not sure how many bytes were read

}

if length == 0 {

return nil, 1, nil

}

challenge := make([]byte, length)

dn, err := reader.Read(challenge)

return challenge, 1 + int64(dn), err

}