You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
74 lines
1.4 KiB
Go
74 lines
1.4 KiB
Go
6 years ago
|
package plumbing
|
||
|
|
||
|
import (
|
||
|
"bytes"
|
||
|
"crypto/sha1"
|
||
|
"encoding/hex"
|
||
|
"hash"
|
||
|
"sort"
|
||
|
"strconv"
|
||
|
)
|
||
|
|
||
|
// Hash SHA1 hased content
|
||
|
type Hash [20]byte
|
||
|
|
||
|
// ZeroHash is Hash with value zero
|
||
|
var ZeroHash Hash
|
||
|
|
||
|
// ComputeHash compute the hash for a given ObjectType and content
|
||
|
func ComputeHash(t ObjectType, content []byte) Hash {
|
||
|
h := NewHasher(t, int64(len(content)))
|
||
|
h.Write(content)
|
||
|
return h.Sum()
|
||
|
}
|
||
|
|
||
|
// NewHash return a new Hash from a hexadecimal hash representation
|
||
|
func NewHash(s string) Hash {
|
||
|
b, _ := hex.DecodeString(s)
|
||
|
|
||
|
var h Hash
|
||
|
copy(h[:], b)
|
||
|
|
||
|
return h
|
||
|
}
|
||
|
|
||
|
func (h Hash) IsZero() bool {
|
||
|
var empty Hash
|
||
|
return h == empty
|
||
|
}
|
||
|
|
||
|
func (h Hash) String() string {
|
||
|
return hex.EncodeToString(h[:])
|
||
|
}
|
||
|
|
||
|
type Hasher struct {
|
||
|
hash.Hash
|
||
|
}
|
||
|
|
||
|
func NewHasher(t ObjectType, size int64) Hasher {
|
||
|
h := Hasher{sha1.New()}
|
||
|
h.Write(t.Bytes())
|
||
|
h.Write([]byte(" "))
|
||
|
h.Write([]byte(strconv.FormatInt(size, 10)))
|
||
|
h.Write([]byte{0})
|
||
|
return h
|
||
|
}
|
||
|
|
||
|
func (h Hasher) Sum() (hash Hash) {
|
||
|
copy(hash[:], h.Hash.Sum(nil))
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// HashesSort sorts a slice of Hashes in increasing order.
|
||
|
func HashesSort(a []Hash) {
|
||
|
sort.Sort(HashSlice(a))
|
||
|
}
|
||
|
|
||
|
// HashSlice attaches the methods of sort.Interface to []Hash, sorting in
|
||
|
// increasing order.
|
||
|
type HashSlice []Hash
|
||
|
|
||
|
func (p HashSlice) Len() int { return len(p) }
|
||
|
func (p HashSlice) Less(i, j int) bool { return bytes.Compare(p[i][:], p[j][:]) < 0 }
|
||
|
func (p HashSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
|