/**
 * Digital-to-physical conversion.
 *
 * EDF defines the mapping by two calibration points, (digitalMin -> physicalMin)
 * and (digitalMax -> physicalMax), which the specification writes as:
 *
 *   gain     = (physicalMax - physicalMin) / (digitalMax - digitalMin)
 *   physical = (digital - digitalMin) * gain + physicalMin
 *
 * That form is evaluated here in EDFlib's algebraically equivalent arrangement:
 *
 *   offset   = physicalMax / gain - digitalMax
 *   physical = gain * (offset + digital)
 *
 * The rearrangement is not cosmetic. Written the first way, a channel spanning
 * +/-800 uV computes a value near 800 and then subtracts 800, and the cancellation
 * throws away low-order bits: digital 0 yields 0.19536019536019467 when the exact
 * value is 0.19536019536019536. EDFlib's form keeps the intermediate small
 * (offset + digital = 0.5 here) and returns the correctly rounded result.
 *
 * Both properties matter. The values are as accurate as a double can express, and
 * they are bit-identical to pyEDFlib and EDFbrowser, which share EDFlib's arithmetic,
 * so the test suite can assert exact equality against a reference implementation
 * rather than settling for a tolerance.
 */
import type { EdfSignal } from './header.js';
export type Scaler = (digital: number) => number;
export declare function makeScaler(signal: EdfSignal): Scaler;
/**
 * Smallest physical step this channel can express — one digital unit.
 * Used to choose a decimal precision that preserves every distinct sample value.
 */
export declare function quantizationStep(signal: EdfSignal): number;
/**
 * Decimal places needed so that two adjacent digital codes never round to the same
 * string. Two places past the quantization step keep rounding error far below the
 * resolution the hardware actually recorded, without padding the file with digits
 * that carry no information.
 *
 * Ordinary channels land at three or four: a ±800 µV channel over 12 bits steps by
 * 0.39 µV and needs three. The ceiling is only reached by calibrations whose step is
 * below 1e-98, which an 8-character physical bound can still express — `1e-99` is five
 * characters. Those get VALUE_RESOLUTION rather than silence.
 */
export declare function decimalsForSignal(signal: EdfSignal, max?: number): number;
/**
 * Whether this channel's step is finer than any precision the tool can print.
 *
 * Asked of the ceiling, not of the precision in use. `--decimals 2` on a channel needing 3
 * is a trade the caller made knowingly and is not this warning's business — 0.5.10 fixed a
 * version of this that fired on every ordinary EEG at `--decimals 2` and made
 * `--decimals 2 --strict` impossible. But it fixed it by asking "did the caller choose the
 * precision", which suppressed the real case too: at `--decimals 20` a channel stepping by
 * 1e-106 printed every one of its codes as `0.00000000000000000000`, in silence.
 *
 * The question is whether anything the tool can print would separate consecutive codes. When
 * the answer is no, that is a ceiling nobody chose, and it holds whatever `--decimals` says.
 */
export declare function decimalsAreClamped(signal: EdfSignal): boolean;