From c9115f367be2fd0d03d6314428608fdcc89bf48a Mon Sep 17 00:00:00 2001
From: Timofey Solomko <tsolomko@gmail.com>
Date: Mon, 13 Aug 2018 11:38:42 +0300
Subject: [PATCH] [ZIP] Replace stored local header and cd entry in
 ZipEntryInfo with separate actually required properties

---
 Sources/ZIP/ZipContainer.swift | 20 ++++++++------------
 Sources/ZIP/ZipEntryInfo.swift | 23 ++++++++++++++++-------
 2 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/Sources/ZIP/ZipContainer.swift b/Sources/ZIP/ZipContainer.swift
index e7811baa..dd743c56 100644
--- a/Sources/ZIP/ZipContainer.swift
+++ b/Sources/ZIP/ZipContainer.swift
@@ -57,17 +57,13 @@ public class ZipContainer: Container {
     }
 
     private static func getEntryData(from data: Data, using info: ZipEntryInfo) throws -> (data: Data, crcError: Bool) {
-        let hasDataDescriptor = info.localHeader.generalPurposeBitFlags & 0x08 != 0
-
-        // If file has data descriptor, then some values in local header are absent.
-        // So we need to use values from CD entry.
-        var uncompSize = hasDataDescriptor ? info.cdEntry.uncompSize : info.localHeader.uncompSize
-        var compSize = hasDataDescriptor ? info.cdEntry.compSize : info.localHeader.compSize
-        var crc32 = hasDataDescriptor ? info.cdEntry.crc32 : info.localHeader.crc32
+        var uncompSize = info.uncompSize
+        var compSize = info.compSize
+        var crc32 = info.crc
 
         let fileData: Data
         let byteReader = ByteReader(data: data)
-        byteReader.offset = info.localHeader.dataOffset
+        byteReader.offset = info.dataOffset
         switch info.compressionMethod {
         case .copy:
             fileData = Data(bytes: byteReader.bytes(count: uncompSize.toInt()))
@@ -100,9 +96,9 @@ public class ZipContainer: Container {
         default:
             throw ZipError.compressionNotSupported
         }
-        let realCompSize = byteReader.offset - info.localHeader.dataOffset
+        let realCompSize = byteReader.offset - info.dataOffset
 
-        if hasDataDescriptor {
+        if info.hasDataDescriptor {
             // Now we need to parse data descriptor itself.
             // First, it might or might not have signature.
             let ddSignature = byteReader.uint32()
@@ -111,7 +107,7 @@ public class ZipContainer: Container {
             }
             // Now, let's update with values from data descriptor.
             crc32 = byteReader.uint32()
-            if info.localHeader.zip64FieldsArePresent {
+            if info.zip64FieldsArePresent {
                 compSize = byteReader.uint64()
                 uncompSize = byteReader.uint64()
             } else {
@@ -175,7 +171,7 @@ public class ZipContainer: Container {
             let info = try ZipEntryInfo(byteReader, endOfCD.currentDiskNumber)
             entries.append(info)
             // Move to the next Central Directory entry.
-            byteReader.offset = info.cdEntry.nextEntryOffset
+            byteReader.offset = info.nextCdEntryOffset
         }
 
         return entries
diff --git a/Sources/ZIP/ZipEntryInfo.swift b/Sources/ZIP/ZipEntryInfo.swift
index 764050a4..ed19ec32 100644
--- a/Sources/ZIP/ZipEntryInfo.swift
+++ b/Sources/ZIP/ZipEntryInfo.swift
@@ -102,20 +102,22 @@ public struct ZipEntryInfo: ContainerEntryInfo {
     /// CRC32 of entry's data.
     public let crc: UInt32
 
-    let cdEntry: ZipCentralDirectoryEntry
-    let localHeader: ZipLocalHeader
+    let hasDataDescriptor: Bool
+    let zip64FieldsArePresent: Bool
+    let nextCdEntryOffset: Int
+    let dataOffset: Int
+    let compSize: UInt64
+    let uncompSize: UInt64
 
     init(_ byteReader: ByteReader, _ currentDiskNumber: UInt32) throws {
-        // Load and save Central Directory entry.
+        // Read Central Directory entry.
         let cdEntry = try ZipCentralDirectoryEntry(byteReader)
-        self.cdEntry = cdEntry
 
         // Move to the location of Local Header.
         byteReader.offset = cdEntry.localHeaderOffset.toInt()
-        // Load and save Local Header.
+        // Read Local Header.
         let localHeader = try ZipLocalHeader(byteReader)
         try localHeader.validate(with: cdEntry, currentDiskNumber)
-        self.localHeader = localHeader
 
         // If file has data descriptor, then some properties are only present in CD entry.
         self.hasDataDescriptor = localHeader.generalPurposeBitFlags & 0x08 != 0
@@ -172,7 +174,7 @@ public struct ZipEntryInfo: ContainerEntryInfo {
         }
 
         // Size
-        self.size = cdEntry.uncompSize.toInt()
+        self.size = (hasDataDescriptor ? cdEntry.uncompSize : localHeader.uncompSize).toInt()
 
         // External file attributes.
         self.externalFileAttributes = cdEntry.externalFileAttributes
@@ -206,6 +208,13 @@ public struct ZipEntryInfo: ContainerEntryInfo {
         var customExtraFields = cdEntry.customExtraFields
         customExtraFields.append(contentsOf: localHeader.customExtraFields)
         self.customExtraFields = customExtraFields
+
+        // Save some properties from CD entry and Local Header.
+        self.zip64FieldsArePresent = localHeader.zip64FieldsArePresent
+        self.nextCdEntryOffset = cdEntry.nextEntryOffset
+        self.dataOffset = localHeader.dataOffset
+        self.compSize = hasDataDescriptor ? cdEntry.compSize : localHeader.compSize
+        self.uncompSize = hasDataDescriptor ? cdEntry.uncompSize : localHeader.uncompSize
     }
 
 }