mirror of https://github.com/octoleo/restic.git
110 lines
2.9 KiB
Go
110 lines
2.9 KiB
Go
// Copyright (c) 2014, Alexander Neumann <alexander@bumpern.de>
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice, this
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// list of conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// Packgae hashing provides hashing readers and writers.
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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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// Reader is the interfaces that wraps a normal reader. When Hash() is called,
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// it returns the hash for all data that has been read so far.
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type Reader interface {
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io.Reader
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Hash() []byte
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}
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// Writer is the interfaces that wraps a normal writer. When Hash() is called,
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// it returns the hash for all data that has been written so far.
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type Writer interface {
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io.Writer
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Hash() []byte
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}
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type reader struct {
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reader io.Reader
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hash hash.Hash
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}
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// NewReader wraps an io.Reader and in addition feeds all data read through the
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// given hash.
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func NewReader(r io.Reader, h func() hash.Hash) *reader {
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return &reader{
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reader: r,
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hash: h(),
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}
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}
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func (h *reader) Read(p []byte) (int, error) {
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// call original reader
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n, err := h.reader.Read(p)
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// hash bytes
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if n > 0 {
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// hash
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h.hash.Write(p[0:n])
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}
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// return result
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return n, err
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}
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func (h *reader) Hash() []byte {
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return h.hash.Sum([]byte{})
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}
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type writer struct {
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writer io.Writer
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hash hash.Hash
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}
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// NewWriter wraps an io.Reader and in addition feeds all data written through
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// the given hash.
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func NewWriter(w io.Writer, h func() hash.Hash) *writer {
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return &writer{
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writer: w,
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hash: h(),
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}
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}
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func (h *writer) Write(p []byte) (int, error) {
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// call original writer
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n, err := h.writer.Write(p)
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// hash bytes
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if n > 0 {
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// hash
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h.hash.Write(p[0:n])
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}
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// return result
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return n, err
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}
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func (h *writer) Hash() []byte {
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return h.hash.Sum([]byte{})
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}
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