forked from TrueCloudLab/restic
38 lines
846 B
Go
38 lines
846 B
Go
package backend
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import (
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"hash"
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"io"
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)
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// HashingWriter wraps an io.Writer to hashes all data that is written to it.
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type HashingWriter struct {
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w io.Writer
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h hash.Hash
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size int
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}
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// NewHashAppendWriter wraps the writer w and feeds all data written to the hash h.
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func NewHashingWriter(w io.Writer, h hash.Hash) *HashingWriter {
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return &HashingWriter{
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h: h,
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w: io.MultiWriter(w, h),
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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 *HashingWriter) Write(p []byte) (int, error) {
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n, err := h.w.Write(p)
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h.size += n
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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 *HashingWriter) Sum(d []byte) []byte {
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return h.h.Sum(d)
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}
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// Size returns the number of bytes written to the underlying writer.
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func (h *HashingWriter) Size() int {
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return h.size
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}
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