Function seekSequence

src/core/tools/apply-patch/seek-sequence.ts:110–153

(lines: string[], pattern: string[], start: number, eof: boolean)

 * @returns The starting index of the match, or null if not found
 */
export function seekSequence(lines: string[], pattern: string[], start: number, eof: boolean): number | null {
	if (pattern.length === 0) {
		return start
	}

	// When the pattern is longer than available input, there's no possible match
	if (pattern.length > lines.length) {
		return null
	}

	const searchStart = eof && lines.length >= pattern.length ? lines.length - pattern.length : start

	const maxStart = lines.length - pattern.length

	// Pass 1: Exact match
	for (let i = searchStart; i <= maxStart; i++) {
		if (exactMatch(lines, pattern, i)) {
			return i
		}
	}

	// Pass 2: Trim-end match
	for (let i = searchStart; i <= maxStart; i++) {
		if (trimEndMatch(lines, pattern, i)) {
			return i
		}
	}

	// Pass 3: Trim both sides match
	for (let i = searchStart; i <= maxStart; i++) {
		if (trimMatch(lines, pattern, i)) {
			return i
		}
	}

	// Pass 4: Unicode-normalized match
	for (let i = searchStart; i <= maxStart; i++) {
		if (normalizedMatch(lines, pattern, i)) {
			return i
		}
	}

	return null
}