github.com/uber/kraken@v0.1.4/core/infohash.go (about)

     1  // Copyright (c) 2016-2019 Uber Technologies, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  package core
    15  
    16  import (
    17  	"crypto/sha1"
    18  	"encoding/hex"
    19  	"fmt"
    20  )
    21  
    22  // InfoHash is 20-byte SHA1 hash of the Info struct. It is the authoritative
    23  // identifier for a torrent.
    24  type InfoHash [20]byte
    25  
    26  // NewInfoHashFromHex converts a hexidemical string into an InfoHash
    27  func NewInfoHashFromHex(s string) (InfoHash, error) {
    28  	if len(s) != 40 {
    29  		return InfoHash{}, fmt.Errorf("invalid hash: expected 40 characters, got %d", len(s))
    30  	}
    31  	var h InfoHash
    32  	n, err := hex.Decode(h[:], []byte(s))
    33  	if err != nil {
    34  		return InfoHash{}, fmt.Errorf("invalid hex: %s", err)
    35  	}
    36  	if n != 20 {
    37  		return InfoHash{}, fmt.Errorf("invariant violation: expected 20 bytes, got %d", n)
    38  	}
    39  	return h, nil
    40  }
    41  
    42  // NewInfoHashFromBytes converts raw bytes to an InfoHash.
    43  func NewInfoHashFromBytes(b []byte) InfoHash {
    44  	var h InfoHash
    45  	hasher := sha1.New()
    46  	hasher.Write(b)
    47  	copy(h[:], hasher.Sum(nil))
    48  	return h
    49  }
    50  
    51  // Bytes converts h to raw bytes.
    52  func (h InfoHash) Bytes() []byte {
    53  	return h[:]
    54  }
    55  
    56  // Hex converts h into a hexidemical string.
    57  func (h InfoHash) Hex() string {
    58  	return hex.EncodeToString(h[:])
    59  }
    60  
    61  func (h InfoHash) String() string {
    62  	return h.Hex()
    63  }