diff options
Diffstat (limited to 'swarm/multihash/multihash.go')
-rw-r--r-- | swarm/multihash/multihash.go | 92 |
1 files changed, 0 insertions, 92 deletions
diff --git a/swarm/multihash/multihash.go b/swarm/multihash/multihash.go deleted file mode 100644 index 3306e3a6d..000000000 --- a/swarm/multihash/multihash.go +++ /dev/null @@ -1,92 +0,0 @@ -// Copyright 2018 The go-ethereum Authors -// This file is part of the go-ethereum library. -// -// The go-ethereum library is free software: you can redistribute it and/or modify -// it under the terms of the GNU Lesser General Public License as published by -// the Free Software Foundation, either version 3 of the License, or -// (at your option) any later version. -// -// The go-ethereum library is distributed in the hope that it will be useful, -// but WITHOUT ANY WARRANTY; without even the implied warranty of -// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -// GNU Lesser General Public License for more details. -// -// You should have received a copy of the GNU Lesser General Public License -// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. - -package multihash - -import ( - "bytes" - "encoding/binary" - "errors" - "fmt" -) - -const ( - defaultMultihashLength = 32 - defaultMultihashTypeCode = 0x1b -) - -var ( - multihashTypeCode uint8 - MultihashLength = defaultMultihashLength -) - -func init() { - multihashTypeCode = defaultMultihashTypeCode - MultihashLength = defaultMultihashLength -} - -// check if valid swarm multihash -func isSwarmMultihashType(code uint8) bool { - return code == multihashTypeCode -} - -// GetMultihashLength returns the digest length of the provided multihash -// It will fail if the multihash is not a valid swarm mulithash -func GetMultihashLength(data []byte) (int, int, error) { - cursor := 0 - typ, c := binary.Uvarint(data) - if c <= 0 { - return 0, 0, errors.New("unreadable hashtype field") - } - if !isSwarmMultihashType(uint8(typ)) { - return 0, 0, fmt.Errorf("hash code %x is not a swarm hashtype", typ) - } - cursor += c - hashlength, c := binary.Uvarint(data[cursor:]) - if c <= 0 { - return 0, 0, errors.New("unreadable length field") - } - cursor += c - - // we cheekily assume hashlength < maxint - inthashlength := int(hashlength) - if len(data[c:]) < inthashlength { - return 0, 0, errors.New("length mismatch") - } - return inthashlength, cursor, nil -} - -// FromMulithash returns the digest portion of the multihash -// It will fail if the multihash is not a valid swarm multihash -func FromMultihash(data []byte) ([]byte, error) { - hashLength, _, err := GetMultihashLength(data) - if err != nil { - return nil, err - } - return data[len(data)-hashLength:], nil -} - -// ToMulithash wraps the provided digest data with a swarm mulithash header -func ToMultihash(hashData []byte) []byte { - buf := bytes.NewBuffer(nil) - b := make([]byte, 8) - c := binary.PutUvarint(b, uint64(multihashTypeCode)) - buf.Write(b[:c]) - c = binary.PutUvarint(b, uint64(len(hashData))) - buf.Write(b[:c]) - buf.Write(hashData) - return buf.Bytes() -} |