48 lines
1.7 KiB
Go
48 lines
1.7 KiB
Go
|
// Copyright 2022 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 rawdb
|
||
|
|
|
||
|
|
import "github.com/ethereum/go-ethereum/ethdb"
|
||
|
|
|
||
|
|
// KeyLengthIterator is a wrapper for a database iterator that ensures only key-value pairs
|
||
|
|
// with a specific key length will be returned.
|
||
|
|
type KeyLengthIterator struct {
|
||
|
|
requiredKeyLength int
|
||
|
|
ethdb.Iterator
|
||
|
|
}
|
||
|
|
|
||
|
|
// NewKeyLengthIterator returns a wrapped version of the iterator that will only return key-value
|
||
|
|
// pairs where keys with a specific key length will be returned.
|
||
|
|
func NewKeyLengthIterator(it ethdb.Iterator, keyLen int) ethdb.Iterator {
|
||
|
|
return &KeyLengthIterator{
|
||
|
|
Iterator: it,
|
||
|
|
requiredKeyLength: keyLen,
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (it *KeyLengthIterator) Next() bool {
|
||
|
|
// Return true as soon as a key with the required key length is discovered
|
||
|
|
for it.Iterator.Next() {
|
||
|
|
if len(it.Iterator.Key()) == it.requiredKeyLength {
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Return false when we exhaust the keys in the underlying iterator.
|
||
|
|
return false
|
||
|
|
}
|