/**
 * Encode an exact JavaScript string as one delimiter- and glob-safe segment.
 *
 * Common API-safe ASCII stays compact. Every other UTF-16 code unit uses a
 * lowercase `_xxxx` escape, so lone surrogates never collapse through UTF-8.
 * The leading `s` marker makes the empty string representable. A terminal `_`
 * sentinel prevents a literal `vf-sanitized` suffix from touching the following
 * `:` delimiter and aliasing the API sanitizer's reserved namespace.
 */
export declare function encodeCacheKeyLiteralSegment(value: string): string;
/** Decode only canonical values emitted by {@link encodeCacheKeyLiteralSegment}. */
export declare function decodeCacheKeyLiteralSegment(encoded: string): string | null;
/**
 * Percent-encode a delimiter-separated cache-key segment without rejecting or
 * collapsing lone UTF-16 surrogates.
 *
 * Valid Unicode is byte-for-byte compatible with `encodeURIComponent`.
 * Unpaired surrogates use a `%uXXXX` sentinel. A literal percent sign is encoded
 * as `%25`, so caller text cannot alias a sentinel.
 */
export declare function encodeCacheKeyPercentSegment(value: string): string;
/**
 * Decode a segment emitted by {@link encodeCacheKeyPercentSegment}.
 *
 * Only surrogate-range `%uXXXX` sentinels are accepted, which keeps the decoder
 * injective with ordinary `encodeURIComponent` output.
 */
export declare function decodeCacheKeyPercentSegment(encoded: string): string | null;
/** Encode arbitrary JavaScript strings into an injective cache-key-safe segment. */
export declare function encodeCacheKeySegment(value: string): string;
/** Decode a segment emitted by {@link encodeCacheKeySegment}. */
export declare function decodeCacheKeySegment(encoded: string): string | null;
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