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import { IValue, _ISelection, _Transaction, _Explainer, _SelectExplanation, Stats, nil } from '../interfaces-private.ts';import { FilterBase } from './transform-base.ts';import { LimitStatement } from 'https://deno.land/x/pgsql_ast_parser@12.0.1/mod.ts';import { buildValue } from '../parser/expression-builder.ts';import { withSelection } from '../parser/context.ts';
export function buildLimit(on: _ISelection, limit: LimitStatement) {    return withSelection(on, () => {        const l = limit.limit && buildValue(limit.limit);        const o = limit.offset && buildValue(limit.offset);        return new LimitFilter(on, l, o);    });}
class LimitFilter<T = any> extends FilterBase<T> {
    get index() {        return null;    }
    entropy(t: _Transaction) {        return this.selection.entropy(t);    }
    hasItem(raw: T, t: _Transaction): boolean {        return this.base.hasItem(raw, t);    }
    constructor(private selection: _ISelection<T>, private take: IValue | nil, private skip: IValue | nil) {        super(selection);    }

    stats(t: _Transaction): Stats | null {        return null;    }
    *enumerate(t: _Transaction): Iterable<T> {        let skip = this.skip?.get(null, t) ?? 0;        let take = this.take?.get(null, t) ?? Number.MAX_SAFE_INTEGER;        if (take <= 0) {            return;        }        for (const raw of this.selection.enumerate(t)) {            if (skip > 0) {                skip--;                continue;            }            yield raw;            take--;            if (!take) {                return;            }        }    }


    explain(e: _Explainer): _SelectExplanation {        return {            id: e.idFor(this),            _: 'limit',            take: this.take?.explain(e),            skip: this.skip?.explain(e),            on: this.selection.explain(e),        };    }}