116 lines
3.2 KiB
Go
116 lines
3.2 KiB
Go
// Copyright 2025 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 common
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import (
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"iter"
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)
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// Range represents a range of integers.
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type Range[T uint32 | uint64] struct {
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first, afterLast T
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}
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// NewRange creates a new range based of first element and number of elements.
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func NewRange[T uint32 | uint64](first, count T) Range[T] {
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return Range[T]{first, first + count}
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}
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// First returns the first element of the range.
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func (r Range[T]) First() T {
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return r.first
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}
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// Last returns the last element of the range. This panics for empty ranges.
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func (r Range[T]) Last() T {
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if r.first == r.afterLast {
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panic("last item of zero length range is not allowed")
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}
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return r.afterLast - 1
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}
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// AfterLast returns the first element after the range. This allows obtaining
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// information about the end part of zero length ranges.
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func (r Range[T]) AfterLast() T {
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return r.afterLast
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}
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// Count returns the number of elements in the range.
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func (r Range[T]) Count() T {
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return r.afterLast - r.first
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}
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// IsEmpty returns true if the range is empty.
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func (r Range[T]) IsEmpty() bool {
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return r.first == r.afterLast
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}
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// Includes returns true if the given element is inside the range.
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func (r Range[T]) Includes(v T) bool {
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return v >= r.first && v < r.afterLast
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}
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// SetFirst updates the first element of the list.
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func (r *Range[T]) SetFirst(v T) {
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r.first = v
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if r.afterLast < r.first {
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r.afterLast = r.first
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}
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}
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// SetAfterLast updates the end of the range by specifying the first element
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// after the range. This allows setting zero length ranges.
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func (r *Range[T]) SetAfterLast(v T) {
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r.afterLast = v
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if r.afterLast < r.first {
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r.first = r.afterLast
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}
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}
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// SetLast updates last element of the range.
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func (r *Range[T]) SetLast(v T) {
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r.SetAfterLast(v + 1)
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}
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// Intersection returns the intersection of two ranges.
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func (r Range[T]) Intersection(q Range[T]) Range[T] {
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i := Range[T]{first: max(r.first, q.first), afterLast: min(r.afterLast, q.afterLast)}
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if i.first > i.afterLast {
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return Range[T]{}
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}
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return i
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}
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// Union returns the union of two ranges. Panics for gapped ranges.
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func (r Range[T]) Union(q Range[T]) Range[T] {
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if max(r.first, q.first) > min(r.afterLast, q.afterLast) {
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panic("cannot create union; gap between ranges")
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}
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return Range[T]{first: min(r.first, q.first), afterLast: max(r.afterLast, q.afterLast)}
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}
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// Iter iterates all integers in the range.
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func (r Range[T]) Iter() iter.Seq[T] {
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return func(yield func(T) bool) {
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for i := r.first; i < r.afterLast; i++ {
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if !yield(i) {
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break
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}
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}
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}
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}
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