43 lines
1.6 KiB
Go
43 lines
1.6 KiB
Go
// Package resumable registers resumable versions of hash functions. Resumable
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// varieties of hash functions are available via the standard crypto package.
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// Support can be checked by type assertion against the resumable.Hash
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// interface.
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//
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// While one can use these sub-packages directly, it makes more sense to
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// register them using side-effect imports:
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//
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// import _ "github.com/stevvooe/resumable/sha256"
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//
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// This will make the resumable hashes available to the application through
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// the standard crypto package. For example, if a new sha256 is required, one
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// should use the following:
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//
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// h := crypto.SHA256.New()
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//
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// Such a features allows one to control the inclusion of resumable hash
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// support in a single file. Applications that require the resumable hash
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// implementation can type switch to detect support, while other parts of the
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// application can be completely oblivious to the presence of the alternative
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// hash functions.
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//
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// Also note that the implementations available in this package are completely
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// untouched from their Go counterparts in the standard library. Only an extra
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// file is added to each package to implement the extra resumable hash
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// functions.
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package resumable
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import "hash"
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// Hash is the common interface implemented by all resumable hash functions.
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type Hash interface {
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hash.Hash
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// Len returns the number of bytes written to the Hash so far.
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Len() int64
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// State returns a snapshot of the state of the Hash.
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State() ([]byte, error)
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// Restore resets the Hash to the given state.
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Restore(state []byte) error
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}
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