harness-drone/yaml/checksum/checksum.go
2016-04-21 01:18:20 -07:00

70 lines
1.3 KiB
Go

package checksum
import (
"crypto/sha1"
"crypto/sha256"
"crypto/sha512"
"fmt"
"io"
"strings"
)
// Check is a calculates and verifies a file checksum. This supports the sha1,
// sha256 and sha512 values.
func Check(in, checksum string) bool {
hash, size, _ := split(checksum)
// if a byte size is provided for the
// Yaml file it must match.
if size > 0 && int64(len(in)) != size {
return false
}
switch len(hash) {
case 64:
return sha256sum(in) == hash
case 128:
return sha512sum(in) == hash
case 40:
return sha1sum(in) == hash
}
return false
}
func sha1sum(in string) string {
h := sha1.New()
io.WriteString(h, in)
return fmt.Sprintf("%x", h.Sum(nil))
}
func sha256sum(in string) string {
h := sha256.New()
io.WriteString(h, in)
return fmt.Sprintf("%x", h.Sum(nil))
}
func sha512sum(in string) string {
h := sha512.New()
io.WriteString(h, in)
return fmt.Sprintf("%x", h.Sum(nil))
}
func split(in string) (string, int64, string) {
var hash string
var name string
var size int64
// the checksum might be split into multiple
// sections including the file size and name.
switch strings.Count(in, " ") {
case 1:
fmt.Sscanf(in, "%s %s", &hash, &name)
case 2:
fmt.Sscanf(in, "%s %d %s", &hash, &size, &name)
default:
hash = in
}
return hash, size, name
}