70 lines
1.2 KiB
Go
70 lines
1.2 KiB
Go
package destination
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import (
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"crypto/md5"
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"crypto/sha1"
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"crypto/sha256"
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"crypto/sha512"
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"encoding/hex"
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"hash"
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"io"
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)
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var hashFactories = map[string](func() hash.Hash){
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"md5": md5.New,
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"sha1": sha1.New,
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"sha256": sha256.New,
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"sha512": sha512.New,
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}
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func factories() map[string](func() hash.Hash) {
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return hashFactories
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}
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type multiHash struct {
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io.Writer
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hashes map[string]hash.Hash
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}
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func permittedHashFunction(hashFunctions []string, hash string) bool {
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if len(hashFunctions) == 0 {
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return true
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}
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for _, name := range hashFunctions {
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if name == hash {
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return true
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}
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}
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return false
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}
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func newMultiHash(hashFunctions []string) (m *multiHash) {
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m = &multiHash{}
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m.hashes = make(map[string]hash.Hash)
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var writers []io.Writer
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for hash, hashFactory := range factories() {
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if !permittedHashFunction(hashFunctions, hash) {
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continue
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}
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writer := hashFactory()
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m.hashes[hash] = writer
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writers = append(writers, writer)
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}
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m.Writer = io.MultiWriter(writers...)
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return m
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}
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func (m *multiHash) finish() map[string]string {
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h := make(map[string]string)
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for hashName, hash := range m.hashes {
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checksum := hash.Sum(nil)
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h[hashName] = hex.EncodeToString(checksum)
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}
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return h
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}
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