mirror of https://github.com/octoleo/restic.git
41 lines
843 B
Go
41 lines
843 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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// Writer transparently hashes all data while writing it to the underlying writer.
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type Writer struct {
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w io.Writer
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h hash.Hash
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}
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// NewWriter wraps the writer w and feeds all data written to the hash h.
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func NewWriter(w io.Writer, h hash.Hash) *Writer {
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return &Writer{
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h: h,
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w: w,
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}
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}
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// Write wraps the write method of the underlying writer and also hashes all data.
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func (h *Writer) Write(p []byte) (int, error) {
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// write the data to the underlying writing
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n, err := h.w.Write(p)
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// according to the interface documentation, Write() on a hash.Hash never
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// returns an error.
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_, hashErr := h.h.Write(p[:n])
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if hashErr != nil {
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panic(hashErr)
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}
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return n, err
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}
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// Sum returns the hash of all data written so far.
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func (h *Writer) Sum(d []byte) []byte {
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return h.h.Sum(d)
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}
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