forked from TrueCloudLab/distribution
52 lines
1.3 KiB
Go
52 lines
1.3 KiB
Go
// +build !noresumabledigest
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package digest
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import (
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"fmt"
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"github.com/jlhawn/go-crypto"
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// For ResumableHash
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_ "github.com/jlhawn/go-crypto/sha256" // For Resumable SHA256
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_ "github.com/jlhawn/go-crypto/sha512" // For Resumable SHA384, SHA512
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)
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// resumableDigester implements ResumableDigester.
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type resumableDigester struct {
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alg string
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crypto.ResumableHash
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}
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var resumableHashAlgs = map[string]crypto.Hash{
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"sha256": crypto.SHA256,
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"sha384": crypto.SHA384,
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"sha512": crypto.SHA512,
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}
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// NewResumableDigester creates a new ResumableDigester with the given hashing
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// algorithm.
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func NewResumableDigester(alg string) (ResumableDigester, error) {
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hash, supported := resumableHashAlgs[alg]
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if !supported {
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return resumableDigester{}, fmt.Errorf("unsupported resumable hash algorithm: %s", alg)
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}
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return resumableDigester{
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alg: alg,
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ResumableHash: hash.New(),
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}, nil
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}
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// NewCanonicalResumableDigester creates a ResumableDigester using the default
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// digest algorithm.
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func NewCanonicalResumableDigester() ResumableDigester {
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return resumableDigester{
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alg: "sha256",
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ResumableHash: crypto.SHA256.New(),
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}
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}
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// Digest returns the current digest for this resumable digester.
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func (d resumableDigester) Digest() Digest {
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return NewDigest(d.alg, d.ResumableHash)
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}
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