forked from cerc-io/plugeth
48 lines
1.7 KiB
Go
48 lines
1.7 KiB
Go
// Copyright 2022 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package rawdb
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import "github.com/ethereum/go-ethereum/ethdb"
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// KeyLengthIterator is a wrapper for a database iterator that ensures only key-value pairs
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// with a specific key length will be returned.
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type KeyLengthIterator struct {
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requiredKeyLength int
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ethdb.Iterator
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}
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// NewKeyLengthIterator returns a wrapped version of the iterator that will only return key-value
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// pairs where keys with a specific key length will be returned.
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func NewKeyLengthIterator(it ethdb.Iterator, keyLen int) ethdb.Iterator {
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return &KeyLengthIterator{
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Iterator: it,
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requiredKeyLength: keyLen,
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}
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}
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func (it *KeyLengthIterator) Next() bool {
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// Return true as soon as a key with the required key length is discovered
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for it.Iterator.Next() {
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if len(it.Iterator.Key()) == it.requiredKeyLength {
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return true
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}
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}
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// Return false when we exhaust the keys in the underlying iterator.
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return false
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}
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