feat: 初始化 Live Photo 项目结构
- 添加 PRD、技术规范、交互规范文档 (V0.2) - 创建 Swift Package 和 Xcode 项目 - 实现 LivePhotoCore 基础模块 - 添加 HEIC MakerNote 元数据写入功能 - 创建项目结构文档和任务清单 - 添加 .gitignore 忽略规则
This commit is contained in:
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591
Sources/LivePhotoCore/HEICMakerNotePatcher.swift
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591
Sources/LivePhotoCore/HEICMakerNotePatcher.swift
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import Foundation
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/// HEIC 文件结构解析和 MakerNotes 二进制注入
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/// 用于绕过 CGImageDestination 无法正确写入 Int64 MakerNotes 字段的限制
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public enum HEICMakerNoteError: Error, CustomStringConvertible {
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case invalidHEIC(String)
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case metaNotFound
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case iinfNotFound
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case ilocNotFound
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case exifItemNotFound
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case exifLocationNotFound(itemID: UInt32)
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case exifPayloadTooSmall
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case tiffNotFound
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case invalidTIFF(String)
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case exifIFDPointerNotFound
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case makerNoteTagNotFound
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case makerNoteOutOfRange
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case makerNoteTooShort(available: Int, required: Int)
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public var description: String {
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switch self {
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case .invalidHEIC(let msg): return "Invalid HEIC: \(msg)"
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case .metaNotFound: return "meta box not found"
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case .iinfNotFound: return "iinf box not found"
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case .ilocNotFound: return "iloc box not found"
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case .exifItemNotFound: return "Exif item not found"
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case .exifLocationNotFound(let id): return "Exif item location not found for item_ID=\(id)"
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case .exifPayloadTooSmall: return "Exif payload too small"
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case .tiffNotFound: return "TIFF header not found"
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case .invalidTIFF(let msg): return "Invalid TIFF: \(msg)"
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case .exifIFDPointerNotFound: return "ExifIFDPointer (0x8769) not found"
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case .makerNoteTagNotFound: return "MakerNote tag (0x927C) not found"
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case .makerNoteOutOfRange: return "MakerNote data out of range"
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case .makerNoteTooShort(let available, let required):
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return "MakerNote too short: available=\(available), required=\(required)"
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}
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}
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}
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public final class HEICMakerNotePatcher {
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// MARK: - Public API
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/// 将完整的 MakerNotes 数据注入到 HEIC 文件中
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/// 采用重建 Exif item 的方式，支持扩展 MakerNote 大小
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public static func injectMakerNoteInPlace(fileURL: URL, makerNote: Data) throws {
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var fileData = try Data(contentsOf: fileURL, options: [.mappedIfSafe])
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// 解析文件结构
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let metaRange = try findTopLevelBox(type: "meta", in: fileData)
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guard let metaRange else { throw HEICMakerNoteError.metaNotFound }
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let meta = BoxView(data: fileData, range: metaRange)
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let metaChildrenStart = meta.contentStart + 4
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guard metaChildrenStart <= meta.end else {
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throw HEICMakerNoteError.invalidHEIC("meta content too short")
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}
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guard let iinfRange = try findChildBox(type: "iinf", within: metaChildrenStart..<meta.end, in: fileData) else {
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throw HEICMakerNoteError.iinfNotFound
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}
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guard let ilocRange = try findChildBox(type: "iloc", within: metaChildrenStart..<meta.end, in: fileData) else {
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throw HEICMakerNoteError.ilocNotFound
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}
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let exifItemID = try parseIINFAndFindExifItemID(data: fileData, iinfRange: iinfRange)
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let (locations, ilocInfo) = try parseILOCWithInfo(data: fileData, ilocRange: ilocRange)
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guard let exifLoc = locations[exifItemID] else {
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throw HEICMakerNoteError.exifLocationNotFound(itemID: exifItemID)
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}
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let exifStart = Int(exifLoc.offset)
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let exifLen = Int(exifLoc.length)
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guard exifStart >= 0, exifLen > 0, exifStart + exifLen <= fileData.count else {
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throw HEICMakerNoteError.exifPayloadTooSmall
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}
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// 读取现有 Exif item
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let existingExif = fileData.subdata(in: exifStart..<(exifStart + exifLen))
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// 构建新的 Exif item（替换 MakerNote）
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let newExif = try buildNewExifItem(existingExif: existingExif, newMakerNote: makerNote)
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if newExif.count <= exifLen {
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// 新 Exif 不大于原来的，直接原位替换
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var paddedExif = newExif
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if paddedExif.count < exifLen {
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paddedExif.append(Data(repeating: 0x00, count: exifLen - paddedExif.count))
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}
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fileData.replaceSubrange(exifStart..<(exifStart + exifLen), with: paddedExif)
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} else {
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// 新 Exif 比原来大，需要追加到文件末尾并更新 iloc
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let newExifOffset = fileData.count
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fileData.append(newExif)
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// 更新 iloc 中的 offset 和 length
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try updateILOC(
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in: &fileData,
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ilocRange: ilocRange,
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ilocInfo: ilocInfo,
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itemID: exifItemID,
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newOffset: UInt64(newExifOffset),
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newLength: UInt64(newExif.count)
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)
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}
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try fileData.write(to: fileURL, options: [.atomic])
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}
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// MARK: - Build New Exif Item
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/// 构建新的 Exif item，替换 MakerNote
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private static func buildNewExifItem(existingExif: Data, newMakerNote: Data) throws -> Data {
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guard existingExif.count >= 10 else {
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throw HEICMakerNoteError.exifPayloadTooSmall
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}
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// Exif item 结构：
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// 4 bytes: TIFF header offset (通常是 6，指向 "Exif\0\0" 之后)
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// 4 bytes: "Exif"
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// 2 bytes: \0\0
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// 然后是 TIFF 数据
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let tiffOffsetValue = existingExif.readUInt32BE(at: 0)
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let tiffStart = 4 + Int(tiffOffsetValue)
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guard tiffStart + 8 <= existingExif.count else {
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throw HEICMakerNoteError.tiffNotFound
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}
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// 检查字节序
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let endianMarker = existingExif.subdata(in: tiffStart..<(tiffStart + 2))
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let isBigEndian: Bool
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if endianMarker == Data([0x4D, 0x4D]) {
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isBigEndian = true
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} else if endianMarker == Data([0x49, 0x49]) {
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isBigEndian = false
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} else {
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throw HEICMakerNoteError.invalidTIFF("Invalid endian marker")
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}
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// 构建新的 TIFF 数据（Big-Endian，与 Apple 设备一致）
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var newTiff = Data()
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// TIFF Header: "MM" + 0x002A + IFD0 offset (8)
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newTiff.append(contentsOf: [0x4D, 0x4D]) // Big-endian
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newTiff.append(contentsOf: [0x00, 0x2A]) // TIFF magic
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newTiff.append(contentsOf: [0x00, 0x00, 0x00, 0x08]) // IFD0 offset = 8
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// IFD0: 1 entry (ExifIFDPointer)
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// Entry count: 1
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newTiff.append(contentsOf: [0x00, 0x01])
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// Entry: ExifIFDPointer (0x8769)
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let exifIFDOffset: UInt32 = 8 + 2 + 12 + 4 // = 26 (IFD0 之后)
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newTiff.append(contentsOf: [0x87, 0x69]) // tag
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newTiff.append(contentsOf: [0x00, 0x04]) // type = LONG
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newTiff.append(contentsOf: [0x00, 0x00, 0x00, 0x01]) // count = 1
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newTiff.appendUInt32BE(exifIFDOffset) // value = offset to Exif IFD
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// Next IFD offset: 0 (no more IFDs)
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newTiff.append(contentsOf: [0x00, 0x00, 0x00, 0x00])
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// Exif IFD: 1 entry (MakerNote)
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let makerNoteDataOffset: UInt32 = exifIFDOffset + 2 + 12 + 4 // = 44
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newTiff.append(contentsOf: [0x00, 0x01]) // entry count
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// Entry: MakerNote (0x927C)
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newTiff.append(contentsOf: [0x92, 0x7C]) // tag
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newTiff.append(contentsOf: [0x00, 0x07]) // type = UNDEFINED
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newTiff.appendUInt32BE(UInt32(newMakerNote.count)) // count
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newTiff.appendUInt32BE(makerNoteDataOffset) // offset to MakerNote data
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// Next IFD offset: 0
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newTiff.append(contentsOf: [0x00, 0x00, 0x00, 0x00])
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// MakerNote data
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newTiff.append(newMakerNote)
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// 构建完整的 Exif item
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var newExifItem = Data()
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// 4 bytes: offset to TIFF (= 6, 跳过 "Exif\0\0")
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newExifItem.append(contentsOf: [0x00, 0x00, 0x00, 0x06])
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// "Exif\0\0"
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newExifItem.append(contentsOf: [0x45, 0x78, 0x69, 0x66, 0x00, 0x00])
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// TIFF data
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newExifItem.append(newTiff)
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return newExifItem
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}
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// MARK: - Box Parsing
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private struct BoxHeader {
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let type: String
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let size: Int
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let headerSize: Int
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let contentStart: Int
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let end: Int
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}
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private struct BoxView {
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let data: Data
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let range: Range<Int>
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var start: Int { range.lowerBound }
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var end: Int { range.upperBound }
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var header: BoxHeader {
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let size32 = Int(data.readUInt32BE(at: start))
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let type = data.readFourCC(at: start + 4)
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if size32 == 1 {
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let size64 = Int(data.readUInt64BE(at: start + 8))
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return BoxHeader(
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type: type,
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size: size64,
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headerSize: 16,
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contentStart: start + 16,
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end: start + size64
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)
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} else if size32 == 0 {
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return BoxHeader(
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type: type,
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size: data.count - start,
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headerSize: 8,
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contentStart: start + 8,
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end: data.count
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)
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} else {
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return BoxHeader(
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type: type,
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size: size32,
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headerSize: 8,
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contentStart: start + 8,
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end: start + size32
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)
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}
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}
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var contentStart: Int { header.contentStart }
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}
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private static func findTopLevelBox(type: String, in data: Data) throws -> Range<Int>? {
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var cursor = 0
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while cursor + 8 <= data.count {
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let box = try readBoxHeader(at: cursor, data: data)
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if box.type == type { return cursor..<box.end }
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cursor = box.end
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}
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return nil
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}
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private static func findChildBox(type: String, within range: Range<Int>, in data: Data) throws -> Range<Int>? {
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var cursor = range.lowerBound
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while cursor + 8 <= range.upperBound {
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let box = try readBoxHeader(at: cursor, data: data)
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if box.type == type { return cursor..<min(box.end, range.upperBound) }
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cursor = box.end
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}
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return nil
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}
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private static func readBoxHeader(at offset: Int, data: Data) throws -> BoxHeader {
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guard offset + 8 <= data.count else {
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throw HEICMakerNoteError.invalidHEIC("box header out of bounds")
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}
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let size32 = Int(data.readUInt32BE(at: offset))
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let type = data.readFourCC(at: offset + 4)
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if size32 == 1 {
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guard offset + 16 <= data.count else {
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throw HEICMakerNoteError.invalidHEIC("large size box header out of bounds")
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}
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let size64 = Int(data.readUInt64BE(at: offset + 8))
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guard size64 >= 16 else {
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throw HEICMakerNoteError.invalidHEIC("invalid box size")
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}
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return BoxHeader(type: type, size: size64, headerSize: 16, contentStart: offset + 16, end: offset + size64)
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} else if size32 == 0 {
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return BoxHeader(type: type, size: data.count - offset, headerSize: 8, contentStart: offset + 8, end: data.count)
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} else {
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guard size32 >= 8 else {
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throw HEICMakerNoteError.invalidHEIC("invalid box size")
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}
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return BoxHeader(type: type, size: size32, headerSize: 8, contentStart: offset + 8, end: offset + size32)
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}
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}
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// MARK: - iinf / infe Parsing
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private static func parseIINFAndFindExifItemID(data: Data, iinfRange: Range<Int>) throws -> UInt32 {
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let iinf = BoxView(data: data, range: iinfRange).header
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var cursor = iinf.contentStart
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guard cursor + 4 <= iinf.end else {
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throw HEICMakerNoteError.invalidHEIC("iinf too short")
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}
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let version = data.readUInt8(at: cursor)
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cursor += 4
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let entryCount: UInt32
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if version == 0 {
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entryCount = UInt32(data.readUInt16BE(at: cursor))
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cursor += 2
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} else {
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entryCount = data.readUInt32BE(at: cursor)
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cursor += 4
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}
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var foundExif: UInt32?
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var scanned: UInt32 = 0
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while cursor + 8 <= iinf.end, scanned < entryCount {
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let infe = try readBoxHeader(at: cursor, data: data)
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guard infe.type == "infe" else {
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cursor = infe.end
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continue
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}
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var p = infe.contentStart
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guard p + 4 <= infe.end else {
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throw HEICMakerNoteError.invalidHEIC("infe too short")
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}
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let infeVersion = data.readUInt8(at: p)
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p += 4
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let itemID: UInt32
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if infeVersion >= 3 {
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itemID = data.readUInt32BE(at: p); p += 4
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} else {
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itemID = UInt32(data.readUInt16BE(at: p)); p += 2
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}
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p += 2 // item_protection_index
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var itemType = ""
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if infeVersion >= 2 {
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guard p + 4 <= infe.end else {
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throw HEICMakerNoteError.invalidHEIC("infe item_type out of bounds")
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}
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itemType = data.readFourCC(at: p)
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p += 4
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}
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if itemType == "Exif" {
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foundExif = itemID
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break
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}
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cursor = infe.end
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scanned += 1
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}
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guard let exifID = foundExif else {
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throw HEICMakerNoteError.exifItemNotFound
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}
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return exifID
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}
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// MARK: - iloc Parsing
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private struct ItemLocation {
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let offset: UInt64
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let length: UInt64
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}
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private struct ILOCInfo {
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let version: UInt8
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let offsetSize: Int
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let lengthSize: Int
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let baseOffsetSize: Int
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let indexSize: Int
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let itemEntries: [UInt32: ILOCItemEntry]
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}
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private struct ILOCItemEntry {
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let itemID: UInt32
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let extentOffsetPosition: Int // 文件中 extent_offset 字段的位置
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let extentLengthPosition: Int // 文件中 extent_length 字段的位置
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}
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private static func parseILOCWithInfo(data: Data, ilocRange: Range<Int>) throws -> ([UInt32: ItemLocation], ILOCInfo) {
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let iloc = BoxView(data: data, range: ilocRange).header
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var cursor = iloc.contentStart
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guard cursor + 4 <= iloc.end else {
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throw HEICMakerNoteError.invalidHEIC("iloc too short")
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}
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let version = data.readUInt8(at: cursor)
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cursor += 4
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guard cursor + 2 <= iloc.end else {
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throw HEICMakerNoteError.invalidHEIC("iloc header out of bounds")
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}
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let offsetSize = Int(data.readUInt8(at: cursor) >> 4)
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let lengthSize = Int(data.readUInt8(at: cursor) & 0x0F)
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cursor += 1
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let baseOffsetSize = Int(data.readUInt8(at: cursor) >> 4)
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let indexSize = Int(data.readUInt8(at: cursor) & 0x0F)
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cursor += 1
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let itemCount: UInt32
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if version < 2 {
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guard cursor + 2 <= iloc.end else {
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throw HEICMakerNoteError.invalidHEIC("iloc item_count out of bounds")
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}
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itemCount = UInt32(data.readUInt16BE(at: cursor))
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cursor += 2
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} else {
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guard cursor + 4 <= iloc.end else {
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throw HEICMakerNoteError.invalidHEIC("iloc item_count out of bounds")
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}
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itemCount = data.readUInt32BE(at: cursor)
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cursor += 4
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}
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var locations: [UInt32: ItemLocation] = [:]
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var itemEntries: [UInt32: ILOCItemEntry] = [:]
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for _ in 0..<itemCount {
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guard cursor + 2 <= iloc.end else { break }
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let itemID: UInt32
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if version < 2 {
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itemID = UInt32(data.readUInt16BE(at: cursor)); cursor += 2
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} else {
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guard cursor + 4 <= iloc.end else { break }
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itemID = data.readUInt32BE(at: cursor); cursor += 4
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}
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if version == 1 || version == 2 {
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guard cursor + 2 <= iloc.end else { break }
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cursor += 2
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}
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guard cursor + 2 <= iloc.end else { break }
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cursor += 2
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guard cursor + baseOffsetSize <= iloc.end else { break }
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let baseOffset = try data.readUIntBE(at: cursor, size: baseOffsetSize)
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cursor += baseOffsetSize
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guard cursor + 2 <= iloc.end else { break }
|
||||
let extentCount = Int(data.readUInt16BE(at: cursor))
|
||||
cursor += 2
|
||||
|
||||
var firstExtentOffset: UInt64 = 0
|
||||
var firstExtentLength: UInt64 = 0
|
||||
var extentOffsetPos = 0
|
||||
var extentLengthPos = 0
|
||||
|
||||
for e in 0..<extentCount {
|
||||
if (version == 1 || version == 2) && indexSize > 0 {
|
||||
guard cursor + indexSize <= iloc.end else { break }
|
||||
cursor += indexSize
|
||||
}
|
||||
|
||||
guard cursor + offsetSize + lengthSize <= iloc.end else { break }
|
||||
|
||||
if e == 0 {
|
||||
extentOffsetPos = cursor
|
||||
}
|
||||
let extentOffset = try data.readUIntBE(at: cursor, size: offsetSize)
|
||||
cursor += offsetSize
|
||||
|
||||
if e == 0 {
|
||||
extentLengthPos = cursor
|
||||
}
|
||||
let extentLength = try data.readUIntBE(at: cursor, size: lengthSize)
|
||||
cursor += lengthSize
|
||||
|
||||
if e == 0 {
|
||||
firstExtentOffset = extentOffset
|
||||
firstExtentLength = extentLength
|
||||
}
|
||||
}
|
||||
|
||||
let fileOffset = baseOffset + firstExtentOffset
|
||||
if firstExtentLength > 0 {
|
||||
locations[itemID] = ItemLocation(offset: fileOffset, length: firstExtentLength)
|
||||
itemEntries[itemID] = ILOCItemEntry(
|
||||
itemID: itemID,
|
||||
extentOffsetPosition: extentOffsetPos,
|
||||
extentLengthPosition: extentLengthPos
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
let info = ILOCInfo(
|
||||
version: version,
|
||||
offsetSize: offsetSize,
|
||||
lengthSize: lengthSize,
|
||||
baseOffsetSize: baseOffsetSize,
|
||||
indexSize: indexSize,
|
||||
itemEntries: itemEntries
|
||||
)
|
||||
|
||||
return (locations, info)
|
||||
}
|
||||
|
||||
private static func updateILOC(
|
||||
in fileData: inout Data,
|
||||
ilocRange: Range<Int>,
|
||||
ilocInfo: ILOCInfo,
|
||||
itemID: UInt32,
|
||||
newOffset: UInt64,
|
||||
newLength: UInt64
|
||||
) throws {
|
||||
guard let entry = ilocInfo.itemEntries[itemID] else {
|
||||
throw HEICMakerNoteError.exifLocationNotFound(itemID: itemID)
|
||||
}
|
||||
|
||||
// 写入新的 offset
|
||||
fileData.writeUIntBE(at: entry.extentOffsetPosition, value: newOffset, size: ilocInfo.offsetSize)
|
||||
|
||||
// 写入新的 length
|
||||
fileData.writeUIntBE(at: entry.extentLengthPosition, value: newLength, size: ilocInfo.lengthSize)
|
||||
}
|
||||
|
||||
// MARK: - EXIF/TIFF Patching
|
||||
|
||||
enum Endian {
|
||||
case little
|
||||
case big
|
||||
}
|
||||
}
|
||||
|
||||
// MARK: - Data Extensions
|
||||
|
||||
private extension Data {
|
||||
func readUInt8(at offset: Int) -> UInt8 {
|
||||
self[self.index(self.startIndex, offsetBy: offset)]
|
||||
}
|
||||
|
||||
func readUInt16BE(at offset: Int) -> UInt16 {
|
||||
let b0 = UInt16(readUInt8(at: offset))
|
||||
let b1 = UInt16(readUInt8(at: offset + 1))
|
||||
return (b0 << 8) | b1
|
||||
}
|
||||
|
||||
func readUInt32BE(at offset: Int) -> UInt32 {
|
||||
let b0 = UInt32(readUInt8(at: offset))
|
||||
let b1 = UInt32(readUInt8(at: offset + 1))
|
||||
let b2 = UInt32(readUInt8(at: offset + 2))
|
||||
let b3 = UInt32(readUInt8(at: offset + 3))
|
||||
return (b0 << 24) | (b1 << 16) | (b2 << 8) | b3
|
||||
}
|
||||
|
||||
func readUInt64BE(at offset: Int) -> UInt64 {
|
||||
var v: UInt64 = 0
|
||||
for i in 0..<8 {
|
||||
v = (v << 8) | UInt64(readUInt8(at: offset + i))
|
||||
}
|
||||
return v
|
||||
}
|
||||
|
||||
func readFourCC(at offset: Int) -> String {
|
||||
let bytes = self.subdata(in: offset..<(offset + 4))
|
||||
return String(bytes: bytes, encoding: .ascii) ?? "????"
|
||||
}
|
||||
|
||||
func readUIntBE(at offset: Int, size: Int) throws -> UInt64 {
|
||||
if size == 0 { return 0 }
|
||||
guard offset + size <= count else {
|
||||
throw HEICMakerNoteError.invalidHEIC("Variable-length integer out of bounds")
|
||||
}
|
||||
var v: UInt64 = 0
|
||||
for i in 0..<size {
|
||||
v = (v << 8) | UInt64(readUInt8(at: offset + i))
|
||||
}
|
||||
return v
|
||||
}
|
||||
|
||||
mutating func appendUInt32BE(_ value: UInt32) {
|
||||
append(UInt8((value >> 24) & 0xFF))
|
||||
append(UInt8((value >> 16) & 0xFF))
|
||||
append(UInt8((value >> 8) & 0xFF))
|
||||
append(UInt8(value & 0xFF))
|
||||
}
|
||||
|
||||
mutating func writeUIntBE(at offset: Int, value: UInt64, size: Int) {
|
||||
for i in 0..<size {
|
||||
let byteIndex = self.index(self.startIndex, offsetBy: offset + i)
|
||||
let shift = (size - 1 - i) * 8
|
||||
self[byteIndex] = UInt8((value >> shift) & 0xFF)
|
||||
}
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user