github.com/core-coin/go-core/v2@v2.1.9/rlp/iterator.go (about) 1 // Copyright 2020 by the Authors 2 // This file is part of the go-core library. 3 // 4 // The go-core library is free software: you can redistribute it and/or modify 5 // it under the terms of the GNU Lesser General Public License as published by 6 // the Free Software Foundation, either version 3 of the License, or 7 // (at your option) any later version. 8 // 9 // The go-core library is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU Lesser General Public License for more details. 13 // 14 // You should have received a copy of the GNU Lesser General Public License 15 // along with the go-core library. If not, see <http://www.gnu.org/licenses/>. 16 17 package rlp 18 19 type listIterator struct { 20 data []byte 21 next []byte 22 err error 23 } 24 25 // NewListIterator creates an iterator for the (list) represented by data 26 func NewListIterator(data RawValue) (*listIterator, error) { 27 k, t, c, err := readKind(data) 28 if err != nil { 29 return nil, err 30 } 31 if k != List { 32 return nil, ErrExpectedList 33 } 34 it := &listIterator{ 35 data: data[t : t+c], 36 } 37 return it, nil 38 39 } 40 41 // Next forwards the iterator one step, returns true if it was not at end yet 42 func (it *listIterator) Next() bool { 43 if len(it.data) == 0 { 44 return false 45 } 46 _, t, c, err := readKind(it.data) 47 it.next = it.data[:t+c] 48 it.data = it.data[t+c:] 49 it.err = err 50 return true 51 } 52 53 // Value returns the current value 54 func (it *listIterator) Value() []byte { 55 return it.next 56 } 57 58 func (it *listIterator) Err() error { 59 return it.err 60 }