btree_iter.go

package main

type btreeIter[T any] struct {
	next  func() (T, bool)
	stop func()
	toRow func(T) Row
}

func NewBTreeRowIter[T any](t *btree.BTreeG[T], ge, lt T, toRow func(T) Row) RowIter {
	next, stop := iter.Pull(func(yield func(T) bool) { t.AscendRange(ge, lt, yield) })
	return &btreeIter[T]{next, stop, toRow}
}

func (it *btreeRowIter[T]) Next(ctx *Context) (Row, error) {
	v, ok := it.next()
	if !ok {
		return nil, io.EOF
	}
	return it.toRow(v), nil
}

func (it *btreeRowIter[T]) Close(*Context) error {
	it.stop()
	return nil
}