mirror of https://github.com/octoleo/restic.git
52 lines
985 B
Go
52 lines
985 B
Go
package hashing
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import (
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"hash"
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"io"
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)
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// ReadSumer hashes all data read from the underlying reader.
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type ReadSumer interface {
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io.Reader
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// Sum returns the hash of the data read so far.
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Sum(d []byte) []byte
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}
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type reader struct {
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io.Reader
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h hash.Hash
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}
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type readWriterTo struct {
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reader
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writerTo io.WriterTo
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}
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// NewReader returns a new ReadSummer that uses the hash h. If the underlying
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// reader supports WriteTo then the returned reader will do so too.
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func NewReader(r io.Reader, h hash.Hash) ReadSumer {
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rs := reader{
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Reader: io.TeeReader(r, h),
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h: h,
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}
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if _, ok := r.(io.WriterTo); ok {
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return &readWriterTo{
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reader: rs,
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writerTo: r.(io.WriterTo),
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}
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}
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return &rs
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}
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// Sum returns the hash of the data read so far.
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func (h *reader) Sum(d []byte) []byte {
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return h.h.Sum(d)
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}
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// WriteTo reads all data into the passed writer
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func (h *readWriterTo) WriteTo(w io.Writer) (int64, error) {
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return h.writerTo.WriteTo(NewWriter(w, h.h))
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}
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