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// Copyright 2014 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package git
import (
"encoding/hex"
"errors"
"fmt"
"strings"
)
var (
IDNotExist = errors.New("sha1 ID does not exist")
)
type sha1 [20]byte
// Return true if s has the same sha1 as caller.
// Support 40-length-string, []byte, sha1
func (id sha1) Equal(s2 interface{}) bool {
switch v := s2.(type) {
case string:
if len(v) != 40 {
return false
}
return v == id.String()
case []byte:
if len(v) != 20 {
return false
}
for i, v := range v {
if id[i] != v {
return false
}
}
case sha1:
for i, v := range v {
if id[i] != v {
return false
}
}
default:
return false
}
return true
}
// Return string (hex) representation of the Oid
func (s sha1) String() string {
result := make([]byte, 0, 40)
hexvalues := []byte("0123456789abcdef")
for i := 0; i < 20; i++ {
result = append(result, hexvalues[s[i]>>4])
result = append(result, hexvalues[s[i]&0xf])
}
return string(result)
}
// Create a new sha1 from a 20 byte slice.
func NewId(b []byte) (sha1, error) {
var id sha1
if len(b) != 20 {
return id, errors.New("Length must be 20")
}
for i := 0; i < 20; i++ {
id[i] = b[i]
}
return id, nil
}
// Create a new sha1 from a Sha1 string of length 40.
func NewIdFromString(s string) (sha1, error) {
s = strings.TrimSpace(s)
var id sha1
if len(s) != 40 {
return id, fmt.Errorf("Length must be 40")
}
b, err := hex.DecodeString(s)
if err != nil {
return id, err
}
return NewId(b)
}
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