go-openssl/sha256.go
JT Olds 42391d89a5 add license
Change-Id: I4642fb9b97256ec6b3ffbe403272efc690bf1606
2014-05-09 15:38:13 -06:00

93 lines
2.2 KiB
Go

// Copyright (C) 2014 Space Monkey, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// +build cgo
package openssl
/*
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "openssl/evp.h"
*/
import "C"
import (
"errors"
"runtime"
"unsafe"
)
type SHA256Hash struct {
ctx C.EVP_MD_CTX
engine *Engine
}
func NewSHA256Hash() (*SHA256Hash, error) { return NewSHA256HashWithEngine(nil) }
func NewSHA256HashWithEngine(e *Engine) (*SHA256Hash, error) {
hash := &SHA256Hash{engine: e}
C.EVP_MD_CTX_init(&hash.ctx)
runtime.SetFinalizer(hash, func(hash *SHA256Hash) { hash.Close() })
if err := hash.Reset(); err != nil {
return nil, err
}
return hash, nil
}
func (s *SHA256Hash) Close() {
C.EVP_MD_CTX_cleanup(&s.ctx)
}
func (s *SHA256Hash) Reset() error {
if 1 != C.EVP_DigestInit_ex(&s.ctx, C.EVP_sha256(), engineRef(s.engine)) {
return errors.New("openssl: sha256: cannot init digest ctx")
}
return nil
}
func (s *SHA256Hash) Write(p []byte) (n int, err error) {
if len(p) == 0 {
return 0, nil
}
if 1 != C.EVP_DigestUpdate(&s.ctx, unsafe.Pointer(&p[0]),
C.size_t(len(p))) {
return 0, errors.New("openssl: sha256: cannot update digest")
}
return len(p), nil
}
func (s *SHA256Hash) Sum() (result [32]byte, err error) {
if 1 != C.EVP_DigestFinal_ex(&s.ctx,
(*C.uchar)(unsafe.Pointer(&result[0])), nil) {
return result, errors.New("openssl: sha256: cannot finalize ctx")
}
return result, s.Reset()
}
func SHA256(data []byte) (result [32]byte, err error) {
hash, err := NewSHA256Hash()
if err != nil {
return result, err
}
defer hash.Close()
if _, err := hash.Write(data); err != nil {
return result, err
}
return hash.Sum()
}