syncthing/vendor/github.com/cznic/zappy/decode.go
2016-06-02 13:53:30 +02:00

39 lines
1015 B
Go

// Copyright 2014 The zappy Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Copyright 2011 The Snappy-Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the SNAPPY-GO-LICENSE file.
package zappy
import (
"encoding/binary"
"errors"
)
// ErrCorrupt reports that the input is invalid.
var ErrCorrupt = errors.New("zappy: corrupt input")
// DecodedLen returns the length of the decoded block.
func DecodedLen(src []byte) (int, error) {
v, _, err := decodedLen(src)
return v, err
}
// decodedLen returns the length of the decoded block and the number of bytes
// that the length header occupied.
func decodedLen(src []byte) (blockLen, headerLen int, err error) {
v, n := binary.Uvarint(src)
if n == 0 {
return 0, 0, ErrCorrupt
}
if uint64(int(v)) != v {
return 0, 0, errors.New("zappy: decoded block is too large")
}
return int(v), n, nil
}