64 lines
1.3 KiB
Go
64 lines
1.3 KiB
Go
package sha512
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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/sha512"
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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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// 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, d.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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// 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, &d.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 d.function {
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case crypto.SHA384, crypto.SHA512, crypto.SHA512_224, crypto.SHA512_256:
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break
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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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