kraken

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// Copyright (c) 2016-2019 Uber Technologies, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//     http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package core
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import (
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	"crypto/sha1"
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	"encoding/hex"
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	"fmt"
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)
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// InfoHash is 20-byte SHA1 hash of the Info struct. It is the authoritative
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// identifier for a torrent.
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type InfoHash [20]byte
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// NewInfoHashFromHex converts a hexidemical string into an InfoHash
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func NewInfoHashFromHex(s string) (InfoHash, error) {
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	if len(s) != 40 {
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		return InfoHash{}, fmt.Errorf("invalid hash: expected 40 characters, got %d", len(s))
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	}
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	var h InfoHash
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	n, err := hex.Decode(h[:], []byte(s))
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	if err != nil {
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		return InfoHash{}, fmt.Errorf("invalid hex: %s", err)
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	}
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	if n != 20 {
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		return InfoHash{}, fmt.Errorf("invariant violation: expected 20 bytes, got %d", n)
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	}
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	return h, nil
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}
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// NewInfoHashFromBytes converts raw bytes to an InfoHash.
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func NewInfoHashFromBytes(b []byte) InfoHash {
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	var h InfoHash
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	hasher := sha1.New()
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	hasher.Write(b)
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	copy(h[:], hasher.Sum(nil))
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	return h
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}
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// Bytes converts h to raw bytes.
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func (h InfoHash) Bytes() []byte {
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	return h[:]
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}
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// Hex converts h into a hexidemical string.
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func (h InfoHash) Hex() string {
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	return hex.EncodeToString(h[:])
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}
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func (h InfoHash) String() string {
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	return h.Hex()
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}
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