forked from TrueCloudLab/distribution
45 lines
1 KiB
Go
45 lines
1 KiB
Go
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package digest
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import (
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"crypto/sha256"
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"hash"
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)
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// Digester calculates the digest of written data. It is functionally
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// equivalent to hash.Hash but provides methods for returning the Digest type
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// rather than raw bytes.
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type Digester struct {
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alg string
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hash hash.Hash
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}
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// NewDigester create a new Digester with the given hashing algorithm and instance
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// of that algo's hasher.
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func NewDigester(alg string, h hash.Hash) Digester {
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return Digester{
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alg: alg,
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hash: h,
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}
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}
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// NewCanonicalDigester is a convenience function to create a new Digester with
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// out default settings.
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func NewCanonicalDigester() Digester {
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return NewDigester("sha256", sha256.New())
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}
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// Write data to the digester. These writes cannot fail.
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func (d *Digester) Write(p []byte) (n int, err error) {
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return d.hash.Write(p)
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}
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// Digest returns the current digest for this digester.
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func (d *Digester) Digest() Digest {
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return NewDigest(d.alg, d.hash)
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}
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// Reset the state of the digester.
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func (d *Digester) Reset() {
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d.hash.Reset()
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}
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