mirror of
https://github.com/tsolomko/SWCompression.git
synced 2026-06-23 14:56:41 +00:00
Timofey Solomko
a9cdb50e85
Also changes were made to adopt this removal. This was done to improve behavior in some corner cases as well as enforce intentional usage of particular integer types.
96 lines
3.2 KiB
Swift
96 lines
3.2 KiB
Swift
// Copyright (c) 2017 Timofey Solomko
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// Licensed under MIT License
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//
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// See LICENSE for license information
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import Foundation
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struct ZipLocalHeader {
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let versionNeeded: UInt16
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let generalPurposeBitFlags: UInt16
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let compressionMethod: UInt16
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let lastModFileTime: UInt16
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let lastModFileDate: UInt16
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let crc32: UInt32
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private(set) var compSize: UInt64
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private(set) var uncompSize: UInt64
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private(set) var zip64FieldsArePresent: Bool = false
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let fileName: String
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private(set) var modificationTimestamp: UInt32?
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private(set) var accessTimestamp: UInt32?
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private(set) var creationTimestamp: UInt32?
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init(_ pointerData: DataWithPointer) throws {
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// Check signature.
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guard pointerData.uint32() == 0x04034b50
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else { throw ZipError.wrongSignature }
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self.versionNeeded = pointerData.uint16()
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self.generalPurposeBitFlags = pointerData.uint16()
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self.compressionMethod = pointerData.uint16()
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self.lastModFileTime = pointerData.uint16()
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self.lastModFileDate = pointerData.uint16()
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self.crc32 = pointerData.uint32()
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self.compSize = pointerData.uint64(count: 4)
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self.uncompSize = pointerData.uint64(count: 4)
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let fileNameLength = pointerData.uint16().toInt()
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let extraFieldLength = pointerData.uint16().toInt()
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guard let fileName = String(data: Data(bytes: pointerData.bytes(count: fileNameLength)),
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encoding: .utf8)
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else { throw ZipError.wrongTextField }
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self.fileName = fileName
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let extraFieldStart = pointerData.index
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while pointerData.index - extraFieldStart < extraFieldLength {
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// There are a lot of possible extra fields.
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let headerID = pointerData.uint16()
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let size = pointerData.uint16().toInt()
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switch headerID {
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case 0x0001: // Zip64
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// In local header both uncompressed size and compressed size fields are required.
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self.uncompSize = pointerData.uint64()
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self.compSize = pointerData.uint64()
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self.zip64FieldsArePresent = true
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case 0x5455: // Extended Timestamp
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let flags = pointerData.byte()
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guard flags & 0xF8 == 0 else { break }
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if flags & 0x01 != 0 {
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self.modificationTimestamp = pointerData.uint32()
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}
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if flags & 0x02 != 0 {
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self.accessTimestamp = pointerData.uint32()
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}
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if flags & 0x04 != 0 {
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self.creationTimestamp = pointerData.uint32()
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}
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default:
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pointerData.index += size
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}
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}
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// Let's check headers's values for consistency.
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guard self.versionNeeded & 0xFF <= 63
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else { throw ZipError.wrongVersion }
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guard self.generalPurposeBitFlags & 0x2000 == 0 &&
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self.generalPurposeBitFlags & 0x40 == 0 &&
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self.generalPurposeBitFlags & 0x01 == 0
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else { throw ZipError.encryptionNotSupported }
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guard self.generalPurposeBitFlags & 0x20 == 0
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else { throw ZipError.patchingNotSupported }
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}
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}
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