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// Copyright 2015 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"
"fmt"
"strings"
)
const EMPTY_SHA = "0000000000000000000000000000000000000000"
type sha1 [20]byte
// Equal returns 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
}
// String returns 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)
}
// MustID always creates a new sha1 from a [20]byte array with no validation of input.
func MustID(b []byte) sha1 {
var id sha1
for i := 0; i < 20; i++ {
id[i] = b[i]
}
return id
}
// NewID creates a new sha1 from a [20]byte array.
func NewID(b []byte) (sha1, error) {
if len(b) != 20 {
return sha1{}, fmt.Errorf("Length must be 20: %v", b)
}
return MustID(b), nil
}
// MustIDFromString always creates a new sha from a ID with no validation of input.
func MustIDFromString(s string) sha1 {
b, _ := hex.DecodeString(s)
return MustID(b)
}
// NewIDFromString creates a new sha1 from a ID string of length 40.
func NewIDFromString(s string) (sha1, error) {
var id sha1
s = strings.TrimSpace(s)
if len(s) != 40 {
return id, fmt.Errorf("Length must be 40: %s", s)
}
b, err := hex.DecodeString(s)
if err != nil {
return id, err
}
return NewID(b)
}
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