func GetFileSHA3(fp string) (hexhash string) {
if DEBUG {
fmt.Printf("GetFileMD5: computing hash for '%s'\n", fp)
}
h := sha3.NewKeccak224()
fd, err := os.Open(fp)
if err != nil {
fmt.Printf("GetFileMD5: can't get MD5 for %s: %s", fp, err)
}
defer func() {
if err := fd.Close(); err != nil {
panic(err)
}
}()
reader := bufio.NewReader(fd)
buf := make([]byte, 4096)
for {
block, err := reader.Read(buf)
if err != nil && err != io.EOF {
panic(err)
}
if block == 0 {
break
}
h.Write(buf[:block])
}
hexhash = fmt.Sprintf("%x %s", h.Sum(nil), fp)
return
}
// getHash calculates the hash of a file.
// It reads a file block by block, and updates a hashsum with each block.
// Reading by blocks consume very little memory, which is needed for large files.
// parameters:
// - fd is an open file descriptor that points to the file to inspect
// - hashType is an integer that define the type of hash
// return:
// - hexhash, the hex encoded hash of the file found at fp
func getHash(fd *os.File, hashType int) (hexhash string) {
if DEBUG {
fmt.Printf("getHash: computing hash for '%s'\n", fd.Name())
}
var h hash.Hash
switch hashType {
case CheckMD5:
h = md5.New()
case CheckSHA1:
h = sha1.New()
case CheckSHA256:
h = sha256.New()
case CheckSHA384:
h = sha512.New384()
case CheckSHA512:
h = sha512.New()
case CheckSHA3_224:
h = sha3.NewKeccak224()
case CheckSHA3_256:
h = sha3.NewKeccak256()
case CheckSHA3_384:
h = sha3.NewKeccak384()
case CheckSHA3_512:
h = sha3.NewKeccak512()
default:
err := fmt.Sprintf("getHash: Unkown hash type %d", hashType)
panic(err)
}
buf := make([]byte, 4096)
var offset int64 = 0
for {
block, err := fd.ReadAt(buf, offset)
if err != nil && err != io.EOF {
panic(err)
}
if block == 0 {
break
}
h.Write(buf[:block])
offset += int64(block)
}
hexhash = fmt.Sprintf("%x", h.Sum(nil))
return
}