f01bcc8f62
Updates resumable hash implementation to Go 1.8 equivalent. This should be a major speedup, since it includes a number of optimizations from Go 1.7. Signed-off-by: Stephen J Day <stephen.day@docker.com>
71 lines
1.4 KiB
Go
71 lines
1.4 KiB
Go
package sha256
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import (
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"bytes"
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"crypto"
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"encoding/gob"
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"github.com/stevvooe/resumable"
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// import to ensure that our init function runs after the standard package
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_ "crypto/sha256"
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)
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// Len returns the number of bytes which have been written to the digest.
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func (d *digest) Len() int64 {
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return int64(d.len)
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}
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// State returns a snapshot of the state of the digest.
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func (d *digest) State() ([]byte, error) {
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var buf bytes.Buffer
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encoder := gob.NewEncoder(&buf)
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function := crypto.SHA256
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if d.is224 {
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function = crypto.SHA224
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}
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// We encode this way so that we do not have
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// to export these fields of the digest struct.
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vals := []interface{}{
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d.h, d.x, d.nx, d.len, function,
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}
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for _, val := range vals {
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if err := encoder.Encode(val); err != nil {
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return nil, err
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}
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}
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return buf.Bytes(), nil
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}
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// Restore resets the digest to the given state.
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func (d *digest) Restore(state []byte) error {
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decoder := gob.NewDecoder(bytes.NewReader(state))
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var function uint
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// We decode this way so that we do not have
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// to export these fields of the digest struct.
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vals := []interface{}{
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&d.h, &d.x, &d.nx, &d.len, &function,
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}
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for _, val := range vals {
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if err := decoder.Decode(val); err != nil {
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return err
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}
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}
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switch crypto.Hash(function) {
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case crypto.SHA224:
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d.is224 = true
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case crypto.SHA256:
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d.is224 = false
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default:
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return resumable.ErrBadState
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}
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return nil
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}
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