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0bf1052abf
* Add Hash Writers * Add the hash writers to the tests * Add the DoubleHash Writer to the benchmarks * Remove buffers from hashing by using the Hash Writer * Replace empty slice with nil in mempool test payload
59 lines
1.6 KiB
Go
59 lines
1.6 KiB
Go
package daghash
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import (
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"crypto/sha256"
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"fmt"
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"hash"
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)
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// HashWriter is used to incrementally hash data without concatenating all of the data to a single buffer
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// it exposes an io.Writer api and a Finalize function to get the resulting hash.
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// HashWriter.Write(slice).Finalize == HashH(slice)
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type HashWriter struct {
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inner hash.Hash
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}
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// DoubleHashWriter is used to incrementally double hash data without concatenating all of the data to a single buffer
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// it exposes an io.Writer api and a Finalize function to get the resulting hash.
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// DoubleHashWriter.Write(slice).Finalize == DoubleHashH(slice)
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type DoubleHashWriter struct {
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inner hash.Hash
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}
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// NewHashWriter returns a new Hash Writer
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func NewHashWriter() *HashWriter {
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return &HashWriter{sha256.New()}
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}
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// Write will always return (len(p), nil)
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func (h *HashWriter) Write(p []byte) (n int, err error) {
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return h.inner.Write(p)
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}
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// Finalize returns the resulting hash
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func (h *HashWriter) Finalize() Hash {
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res := Hash{}
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// Can never happen, Sha256's Sum is 32 bytes.
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err := res.SetBytes(h.inner.Sum(nil))
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if err != nil {
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panic(fmt.Sprintf("Should never fail, sha256.Sum is 32 bytes and so is daghash.Hash: '%+v'", err))
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}
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return res
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}
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// NewDoubleHashWriter Returns a new DoubleHashWriter
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func NewDoubleHashWriter() *DoubleHashWriter {
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return &DoubleHashWriter{sha256.New()}
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}
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// Write will always return (len(p), nil)
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func (h *DoubleHashWriter) Write(p []byte) (n int, err error) {
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return h.inner.Write(p)
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}
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// Finalize returns the resulting double hash
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func (h *DoubleHashWriter) Finalize() Hash {
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firstHashInTheSum := h.inner.Sum(nil)
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return sha256.Sum256(firstHashInTheSum)
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}
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