taglib-wasm/dist/src/taglib/metadata-extent.d.ts

TagLib-Wasm is the universal tagging library for TypeScript/JavaScript platforms: Browsers, Node.js, Deno, Bun, Cloudflare Workers, and Electron apps

/**
 * @fileoverview Is a file's metadata provably contained in its first N bytes?
 *
 * Partial loading (`TagLib.open(path, { partial: true })`) hands TagLib the
 * file's first `maxHeaderSize` bytes concatenated with its last `maxFooterSize`
 * bytes, discarding the middle. That is only sound when the metadata lives
 * entirely inside the header window: otherwise the tag is cut mid-structure and
 * unrelated footer bytes are spliced onto the cut, so TagLib parses whatever
 * lands there. Measured on a real library, 18 of 40 large MP3s read back
 * DIFFERENT metadata that way, and before taglib-f5hp the malformed image also
 * tripped a double free that trapped the whole Wasm module (taglib-f5hp).
 *
 * So the decision is made before splicing, and the rule is deliberately
 * asymmetric: return true ONLY when the metadata is provably contained. Anything
 * unrecognised, malformed, or unbounded answers false, which costs a full read
 * and never costs correctness.
 */
/**
 * True only when the metadata of `header` provably ends within `limit` bytes.
 *
 * `header` is the start of the file and may be shorter than `limit`; anything
 * this cannot prove — an unknown container, a truncated header, a malformed
 * size — answers false so the caller reads the whole file.
 *
 * NOTE this judges the HEADER window only. Trailer metadata (ID3v1, APE) is the
 * caller's business — see trailerFitsInFooter.
 */
export declare function metadataFitsInHeader(header: Uint8Array, limit: number): boolean;
/**
 * True when a file's TRAILER metadata provably fits in the last `footerSize`
 * bytes, given `tail` — the end of the file, at least that long.
 *
 * Partial loading keeps the file's last `footerSize` bytes, so ID3v1 (always
 * exactly 128 bytes) is safe by construction. APEv2 is not: it is unbounded
 * because it can carry cover art, and an APE tag larger than the footer window
 * is spliced so that TagLib computes its start inside the header window's audio
 * and reads nothing. Measured: a 410 KB APE tag lost EVERY tag value silently,
 * while a 41 KB one round-tripped.
 */
export declare function trailerFitsInFooter(tail: Uint8Array, footerSize: number): boolean;
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