package hashenc import ( "hash" "codeberg.org/gruf/go-bytes" ) // HashEncoder defines an interface for calculating encoded hash sums of binary data type HashEncoder interface { // EncodeSum calculates the hash sum of src and encodes (at most) Size() into dst EncodeSum(dst []byte, src []byte) // EncodedSum calculates the encoded hash sum of src and returns data in a newly allocated bytes.Bytes EncodedSum(src []byte) bytes.Bytes // Size returns the expected length of encoded hashes Size() int } // New returns a new HashEncoder instance based on supplied hash.Hash and Encoder supplying functions func New(hash hash.Hash, enc Encoder) HashEncoder { hashSize := hash.Size() return &henc{ hash: hash, hbuf: make([]byte, hashSize), enc: enc, size: enc.EncodedLen(hashSize), } } // henc is the HashEncoder implementation type henc struct { hash hash.Hash hbuf []byte enc Encoder size int } func (henc *henc) EncodeSum(dst []byte, src []byte) { // Hash supplied bytes henc.hash.Reset() henc.hash.Write(src) henc.hbuf = henc.hash.Sum(henc.hbuf[:0]) // Encode the hashsum and return a copy henc.enc.Encode(dst, henc.hbuf) } func (henc *henc) EncodedSum(src []byte) bytes.Bytes { dst := make([]byte, henc.size) henc.EncodeSum(dst, src) return bytes.ToBytes(dst) } func (henc *henc) Size() int { return henc.size }