/**
 * Path helpers shared across all validator checkers.
 *
 * All paths are handled as **forward-slash POSIX strings** because that is
 * how OPC part names are defined. We never touch the host's path separator.
 */
/**
 * Strip a single leading `/` if present. OPC `PartName` values start with
 * `/` by spec, but zip entries do not.
 */
export declare function stripLeadingSlash(p: string): string;
/** `.xml`, `.rels`, or `.vml` — the payloads we parse as XML. */
export declare function isXmlLike(pathName: string): boolean;
/**
 * Directory in which a relationships part's **source** part lives. OPC
 * resolves rel Targets relative to the source part's directory, NOT the
 * `.rels` file's directory. Examples:
 *
 * | .rels path                              | source dir          |
 * |-----------------------------------------|---------------------|
 * | `_rels/.rels`                           | ``                  |
 * | `xl/_rels/workbook.xml.rels`            | `xl`                |
 * | `xl/worksheets/_rels/sheet1.xml.rels`   | `xl/worksheets`     |
 */
export declare function getRelsSourceDir(relsPath: string): string;
/**
 * Basename without directory, e.g. `xl/foo/bar.xml` → `bar.xml`.
 */
export declare function posixBasename(p: string): string;
/** Extension without the leading dot, lowercase. `""` when missing. */
export declare function getExtension(p: string): string;
/**
 * Resolve a relationship Target against a .rels path. Handles absolute
 * targets starting with `/` (relative to package root), `../` traversal,
 * `./`, and plain relative segments. Never returns a leading slash.
 *
 * We do NOT use `node:path` so this module is usable in browsers.
 */
export declare function resolveRelTarget(relsPath: string, target: string): string;
/**
 * `false` when a resolved rel target escapes the package root. Targets
 * that escape are malicious or accidentally produced by broken
 * serialisers and always indicate a corrupt package.
 */
export declare function isSafeResolvedPath(resolved: string): boolean;
/**
 * Derive the .rels path for a given source part. Symmetric with
 * `getRelsSourceDir`. Examples:
 *
 * | source part                    | rels path                              |
 * |--------------------------------|----------------------------------------|
 * | `xl/workbook.xml`              | `xl/_rels/workbook.xml.rels`           |
 * | `xl/worksheets/sheet1.xml`     | `xl/worksheets/_rels/sheet1.xml.rels`  |
 */
export declare function relsPathForPart(partPath: string): string;
/**
 * Inverse of {@link relsPathForPart}: source part for a given rels file.
 * Returns undefined for the root rels (which has no conventional source).
 */
export declare function sourcePartForRels(relsPath: string): string | undefined;
/**
 * Part name satisfies OPC PartName grammar — not empty, uses only safe
 * characters, does not end with `/` and does not contain `.` or `..`
 * segments. We do not validate the full grammar but cover the cases that
 * break Excel in practice.
 */
export declare function isLegalPartName(partName: string): boolean;