/**
 * The two `type="file"` columns the streaming engine resolves itself.
 *
 * ## The exact quantile sweep
 *
 * `read="quantile"` on its own needs nothing here: it is one uniform per row,
 * and the generic per-row path already answers it identically on every engine.
 * `sample="exact"` is different — it hands each row its own point on the sorted
 * sample, and which point follows from a scatter over the WHOLE run. The generic
 * path is handed a count of one and could not know how many rows there are, so
 * it would give every row the median. (Measured, before this existed: a hundred
 * thousand rows all came out 53.30.)
 *
 * Its own module because `stream-build.ts` is at the repo's ceiling on file
 * length, and because the arithmetic belongs beside the generator rather than
 * inside the dispatcher.
 */
import type { DataSourceOptions } from '../data-source/index.js';
import type { GenSpec } from './types.js';
/**
 * The value at a population row, or undefined when this generator is not an
 * exact quantile sweep and the caller should carry on down its other branches.
 *
 * The file is read and sorted ONCE, when the column is prepared — not per row —
 * so a run of any length costs the sample, and nothing more.
 */
export declare function exactQuantileSweep(gen: GenSpec, dataSources: DataSourceOptions, seed: string, streamId: string, size: number): ((row: number) => string) | undefined;
/** Apply a row resolver to a population index that may be filtered out. */
export declare function atRow(row: number | undefined, value: (row: number) => string): string | undefined;
/**
 * A row-linked file field (`row="K"`), or undefined when this is not one.
 *
 * Every field sharing the key must resolve the SAME CSV row for a given card —
 * that is what keeps a name, an email and a city coherent — while the row itself
 * varies per card. The in-memory engine builds a shared plan of `count` indexes;
 * a streaming resolver has no such plan (it answers one card at a time), so it
 * re-derives the card's row from a seekable stream keyed by the LINK, shared
 * across the link's fields and independent of each field's own stream.
 */
export declare function rowLinkedFileValue(gen: GenSpec, dataSources: DataSourceOptions, seed: string): ((card: number) => string) | undefined;
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