/**
 * Streams CSV rows from disk. Spike-day event logs exceed V8's ~512 MB string limit, so the
 * whole-file parser in timeline/loadCaptures.ts cannot be used here. The state machine carries
 * across read chunks, including a quote that ends one chunk.
 */
export declare function readCsvCells(path: string, opts?: {
    chunkSize?: number;
}): AsyncGenerator<string[]>;
export declare function readCsvRecords(path: string, opts?: {
    chunkSize?: number;
}): AsyncGenerator<Record<string, string>>;
export declare function csvLine(cells: readonly string[]): string;
export interface FilterResult {
    totalRows: number;
    guestRows: number;
    guestRowsByUser: Record<string, number>;
    malformed: number;
}
/** A log whose header lacks columns the analysis needs. Thrown before any row is written. */
export declare class MissingColumnsError extends Error {
    readonly missing: string[];
    constructor(missing: string[]);
}
/**
 * Copies the rows whose USER_ID or USER_ID_DERIVED belongs to a guest user; counts every row.
 * A UTF-8 BOM is stripped from the header. `requiredColumns`, when given, returns the columns
 * the header lacks; any at all fails the file closed with MissingColumnsError.
 */
export declare function filterLogFile(rawPath: string, outPath: string, guestIds: ReadonlySet<string>, opts?: {
    requiredColumns?: (header: string[]) => string[];
}): Promise<FilterResult>;
//# sourceMappingURL=csv.d.ts.map