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