github.com/google/syzkaller@v0.0.0-20240517125934-c0f1611a36d6/pkg/hash/hash.go (about)

     1  // Copyright 2016 syzkaller project authors. All rights reserved.
     2  // Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
     3  
     4  package hash
     5  
     6  import (
     7  	"bytes"
     8  	"crypto/sha1"
     9  	"encoding/binary"
    10  	"encoding/hex"
    11  	"fmt"
    12  )
    13  
    14  type Sig [sha1.Size]byte
    15  
    16  func Hash(pieces ...[]byte) Sig {
    17  	h := sha1.New()
    18  	for _, data := range pieces {
    19  		h.Write(data)
    20  	}
    21  	var sig Sig
    22  	copy(sig[:], h.Sum(nil))
    23  	return sig
    24  }
    25  
    26  func String(pieces ...[]byte) string {
    27  	sig := Hash(pieces...)
    28  	return sig.String()
    29  }
    30  
    31  func (sig *Sig) String() string {
    32  	return hex.EncodeToString((*sig)[:])
    33  }
    34  
    35  // Truncate64 returns first 64 bits of the hash as int64.
    36  func (sig *Sig) Truncate64() int64 {
    37  	var v int64
    38  	if err := binary.Read(bytes.NewReader((*sig)[:]), binary.LittleEndian, &v); err != nil {
    39  		panic(fmt.Sprintf("failed convert hash to id: %v", err))
    40  	}
    41  	return v
    42  }
    43  
    44  func FromString(str string) (Sig, error) {
    45  	bin, err := hex.DecodeString(str)
    46  	if err != nil {
    47  		return Sig{}, fmt.Errorf("failed to decode sig '%v': %w", str, err)
    48  	}
    49  	if len(bin) != len(Sig{}) {
    50  		return Sig{}, fmt.Errorf("failed to decode sig '%v': bad len", str)
    51  	}
    52  	var sig Sig
    53  	copy(sig[:], bin[:])
    54  	return sig, err
    55  }