/**
 * Base64-encode raw bytes for `data:` URIs (the svg + html writers). `btoa` is
 * available in browsers, workers and Node 16+; chunking keeps the intermediate
 * binary string small.
 */
export declare function toBase64(bytes: Uint8Array): string;
/**
 * Whether the ZIP in `bytes` holds a part named `partName` — the name exactly,
 * or anything under it when `partName` names a directory (ends with `/`).
 *
 * This is what a reader sniff should ask. A substring probe cannot tell a
 * package from one EMBEDDED in it: a deck with a chart carries the chart's
 * workbook as `ppt/embeddings/*.xlsx` STORED, uncompressed, so that workbook's
 * own `xl/workbook.xml` sits in the outer file's bytes verbatim — and the xlsx
 * sniff, which runs before the pptx one, claimed thirteen corpus presentations
 * and then failed on them. The ZIP's central directory lists what is actually
 * in this package, and walking that entry table is cheaper than scanning every
 * byte for a needle.
 *
 * Names are compared without case, as OPC compares part names (§9.1.1.1) and
 * as the package reader behind the sniff resolves them.
 *
 * @param bytes    The package bytes.
 * @param partName The part name, or a `/`-terminated directory prefix.
 * @returns Whether the package's directory names it.
 */
export declare function packageHasPart(bytes: Uint8Array, partName: string): boolean;
/**
 * Scan raw package bytes for an OPC part name (e.g. `'xl/workbook.xml'`)
 * without unzipping. Prefer {@link packageHasPart}, which asks the archive
 * what it holds instead of hoping the name appears nowhere else. Accepts both
 * the spec's `/` separator and the `\` that Windows producers write.
 */
export declare function bytesIncludePartName(haystack: Uint8Array, partName: string): boolean;
/**
 * Naive scan for an ASCII `needle` inside raw `haystack` bytes. Prefer
 * {@link bytesIncludePartName} for OPC part names — it also accepts the
 * backslash spelling real archives use.
 */
export declare function bytesInclude(haystack: Uint8Array, needle: string): boolean;