react-native-update/ios/RCTHotUpdate/SSZipArchive/SSZipArchive.m

//
//  SSZipArchive.m
//  SSZipArchive
//
//  Created by Sam Soffes on 7/21/10.
//  Copyright (c) Sam Soffes 2010-2015. All rights reserved.
//
#import "SSZipArchive.h"
#include "unzip.h"
#include "zip.h"
#import "zlib.h"
#import "zconf.h"

#include <sys/stat.h>

#define CHUNK 16384

@interface SSZipArchive ()
+ (NSDate *)_dateWithMSDOSFormat:(UInt32)msdosDateTime;
@end

@implementation SSZipArchive
{
    NSString *_path;
    NSString *_filename;
    zipFile _zip;
}

#pragma mark - Unzipping

+ (BOOL)unzipFileAtPath:(NSString *)path toDestination:(NSString *)destination
{
    return [self unzipFileAtPath:path toDestination:destination delegate:nil];
}

+ (BOOL)unzipFileAtPath:(NSString *)path toDestination:(NSString *)destination overwrite:(BOOL)overwrite password:(NSString *)password error:(NSError **)error
{
    return [self unzipFileAtPath:path toDestination:destination overwrite:overwrite password:password error:error delegate:nil progressHandler:nil completionHandler:nil];
}

+ (BOOL)unzipFileAtPath:(NSString *)path toDestination:(NSString *)destination delegate:(id<SSZipArchiveDelegate>)delegate
{
    return [self unzipFileAtPath:path toDestination:destination overwrite:YES password:nil error:nil delegate:delegate progressHandler:nil completionHandler:nil];
}

+ (BOOL)unzipFileAtPath:(NSString *)path toDestination:(NSString *)destination overwrite:(BOOL)overwrite password:(NSString *)password error:(NSError **)error delegate:(id<SSZipArchiveDelegate>)delegate
{
    return [self unzipFileAtPath:path toDestination:destination overwrite:overwrite password:password error:error delegate:delegate progressHandler:nil completionHandler:nil];
}

+ (BOOL)unzipFileAtPath:(NSString *)path
          toDestination:(NSString *)destination
              overwrite:(BOOL)overwrite
               password:(NSString *)password
        progressHandler:(void (^)(NSString *entry, unz_file_info zipInfo, long entryNumber, long total))progressHandler
      completionHandler:(void (^)(NSString *path, BOOL succeeded, NSError *error))completionHandler
{
    return [self unzipFileAtPath:path toDestination:destination overwrite:overwrite password:password error:nil delegate:nil progressHandler:progressHandler completionHandler:completionHandler];
}

+ (BOOL)unzipFileAtPath:(NSString *)path
          toDestination:(NSString *)destination
        progressHandler:(void (^)(NSString *entry, unz_file_info zipInfo, long entryNumber, long total))progressHandler
      completionHandler:(void (^)(NSString *path, BOOL succeeded, NSError *error))completionHandler
{
    return [self unzipFileAtPath:path toDestination:destination overwrite:YES password:nil error:nil delegate:nil progressHandler:progressHandler completionHandler:completionHandler];
}

+ (BOOL)unzipFileAtPath:(NSString *)path
          toDestination:(NSString *)destination
              overwrite:(BOOL)overwrite
               password:(NSString *)password
                  error:(NSError **)error
               delegate:(id<SSZipArchiveDelegate>)delegate
        progressHandler:(void (^)(NSString *entry, unz_file_info zipInfo, long entryNumber, long total))progressHandler
      completionHandler:(void (^)(NSString *path, BOOL succeeded, NSError *error))completionHandler
{
    // Begin opening
    zipFile zip = unzOpen((const char*)[path UTF8String]);
    if (zip == NULL)
    {
        NSDictionary *userInfo = @{NSLocalizedDescriptionKey: @"failed to open zip file"};
        NSError *err = [NSError errorWithDomain:@"SSZipArchiveErrorDomain" code:-1 userInfo:userInfo];
        if (error)
        {
            *error = err;
        }
        if (completionHandler)
        {
            completionHandler(nil, NO, err);
        }
        return NO;
    }
    
    NSDictionary * fileAttributes = [[NSFileManager defaultManager] attributesOfItemAtPath:path error:nil];
    unsigned long long fileSize = [fileAttributes[NSFileSize] unsignedLongLongValue];
    unsigned long long currentPosition = 0;
    
    unz_global_info  globalInfo = {0ul, 0ul};
    unzGetGlobalInfo(zip, &globalInfo);
    
    // Begin unzipping
    if (unzGoToFirstFile(zip) != UNZ_OK)
    {
        NSDictionary *userInfo = @{NSLocalizedDescriptionKey: @"failed to open first file in zip file"};
        NSError *err = [NSError errorWithDomain:@"SSZipArchiveErrorDomain" code:-2 userInfo:userInfo];
        if (error)
        {
            *error = err;
        }
        if (completionHandler)
        {
            completionHandler(nil, NO, err);
        }
        return NO;
    }
    
    BOOL success = YES;
    BOOL canceled = NO;
    int ret = 0;
    int crc_ret =0;
    unsigned char buffer[4096] = {0};
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSMutableSet *directoriesModificationDates = [[NSMutableSet alloc] init];
    
    // Message delegate
    if ([delegate respondsToSelector:@selector(zipArchiveWillUnzipArchiveAtPath:zipInfo:)]) {
        [delegate zipArchiveWillUnzipArchiveAtPath:path zipInfo:globalInfo];
    }
    if ([delegate respondsToSelector:@selector(zipArchiveProgressEvent:total:)]) {
        [delegate zipArchiveProgressEvent:currentPosition total:fileSize];
    }
    
    NSInteger currentFileNumber = 0;
    do {
        @autoreleasepool {
            if ([password length] == 0) {
                ret = unzOpenCurrentFile(zip);
            } else {
                ret = unzOpenCurrentFilePassword(zip, [password cStringUsingEncoding:NSASCIIStringEncoding]);
            }
            
            if (ret != UNZ_OK) {
                success = NO;
                break;
            }
            
            // Reading data and write to file
            unz_file_info fileInfo;
            memset(&fileInfo, 0, sizeof(unz_file_info));
            
            ret = unzGetCurrentFileInfo(zip, &fileInfo, NULL, 0, NULL, 0, NULL, 0);
            if (ret != UNZ_OK) {
                success = NO;
                unzCloseCurrentFile(zip);
                break;
            }
            
            currentPosition += fileInfo.compressed_size;
            
            // Message delegate
            if ([delegate respondsToSelector:@selector(zipArchiveShouldUnzipFileAtIndex:totalFiles:archivePath:fileInfo:)]) {
                if (![delegate zipArchiveShouldUnzipFileAtIndex:currentFileNumber
                                                     totalFiles:(NSInteger)globalInfo.number_entry
                                                    archivePath:path fileInfo:fileInfo]) {
                    success = NO;
                    canceled = YES;
                    break;
                }
            }
            if ([delegate respondsToSelector:@selector(zipArchiveWillUnzipFileAtIndex:totalFiles:archivePath:fileInfo:)]) {
                [delegate zipArchiveWillUnzipFileAtIndex:currentFileNumber totalFiles:(NSInteger)globalInfo.number_entry
                                             archivePath:path fileInfo:fileInfo];
            }
            if ([delegate respondsToSelector:@selector(zipArchiveProgressEvent:total:)]) {
                [delegate zipArchiveProgressEvent:(NSInteger)currentPosition total:(NSInteger)fileSize];
            }
            
            char *filename = (char *)malloc(fileInfo.size_filename + 1);
            if (filename == NULL)
            {
                return NO;
            }
            
            unzGetCurrentFileInfo(zip, &fileInfo, filename, fileInfo.size_filename + 1, NULL, 0, NULL, 0);
            filename[fileInfo.size_filename] = '\0';
            
            //
            // Determine whether this is a symbolic link:
            // - File is stored with 'version made by' value of UNIX (3),
            //   as per http://www.pkware.com/documents/casestudies/APPNOTE.TXT
            //   in the upper byte of the version field.
            // - BSD4.4 st_mode constants are stored in the high 16 bits of the
            //   external file attributes (defacto standard, verified against libarchive)
            //
            // The original constants can be found here:
            //    http://minnie.tuhs.org/cgi-bin/utree.pl?file=4.4BSD/usr/include/sys/stat.h
            //
            const uLong ZipUNIXVersion = 3;
            const uLong BSD_SFMT = 0170000;
            const uLong BSD_IFLNK = 0120000;
            
            BOOL fileIsSymbolicLink = NO;
            if (((fileInfo.version >> 8) == ZipUNIXVersion) && BSD_IFLNK == (BSD_SFMT & (fileInfo.external_fa >> 16))) {
                fileIsSymbolicLink = NO;
            }
            
            // Check if it contains directory
            NSString *strPath = @(filename);
            BOOL isDirectory = NO;
            if (filename[fileInfo.size_filename-1] == '/' || filename[fileInfo.size_filename-1] == '\\') {
                isDirectory = YES;
            }
            free(filename);
            
            // Contains a path
            if ([strPath rangeOfCharacterFromSet:[NSCharacterSet characterSetWithCharactersInString:@"/\\"]].location != NSNotFound) {
                strPath = [strPath stringByReplacingOccurrencesOfString:@"\\" withString:@"/"];
            }
            
            NSString *fullPath = [destination stringByAppendingPathComponent:strPath];
            NSError *err = nil;
            NSDate *modDate = [[self class] _dateWithMSDOSFormat:(UInt32)fileInfo.dosDate];
            NSDictionary *directoryAttr = @{NSFileCreationDate: modDate, NSFileModificationDate: modDate};
            
            if (isDirectory) {
                [fileManager createDirectoryAtPath:fullPath withIntermediateDirectories:YES attributes:directoryAttr  error:&err];
            } else {
                [fileManager createDirectoryAtPath:[fullPath stringByDeletingLastPathComponent] withIntermediateDirectories:YES attributes:directoryAttr error:&err];
            }
            if (nil != err) {
                NSLog(@"[SSZipArchive] Error: %@", err.localizedDescription);
            }
            
            if(!fileIsSymbolicLink)
                [directoriesModificationDates addObject: @{@"path": fullPath, @"modDate": modDate}];
            
            if ([fileManager fileExistsAtPath:fullPath] && !isDirectory && !overwrite) {
                //FIXME: couldBe CRC Check?
                unzCloseCurrentFile(zip);
                ret = unzGoToNextFile(zip);
                continue;
            }
            
            if (!fileIsSymbolicLink) {
                FILE *fp = fopen((const char*)[fullPath UTF8String], "wb");
                while (fp) {
                    int readBytes = unzReadCurrentFile(zip, buffer, 4096);
                    
                    if (readBytes > 0) {
                        fwrite(buffer, readBytes, 1, fp );
                    } else {
                        break;
                    }
                }
                
                if (fp) {
                    if ([[[fullPath pathExtension] lowercaseString] isEqualToString:@"zip"]) {
                        NSLog(@"Unzipping nested .zip file:  %@", [fullPath lastPathComponent]);
                        if ([self unzipFileAtPath:fullPath toDestination:[fullPath stringByDeletingLastPathComponent] overwrite:overwrite password:password error:nil delegate:nil]) {
                            [[NSFileManager defaultManager] removeItemAtPath:fullPath error:nil];
                        }
                    }
                    
                    fclose(fp);
                    
                    // Set the original datetime property
                    if (fileInfo.dosDate != 0) {
                        NSDate *orgDate = [[self class] _dateWithMSDOSFormat:(UInt32)fileInfo.dosDate];
                        NSDictionary *attr = @{NSFileModificationDate: orgDate};
                        
                        if (attr) {
                            if ([fileManager setAttributes:attr ofItemAtPath:fullPath error:nil] == NO) {
                                // Can't set attributes
                                NSLog(@"[SSZipArchive] Failed to set attributes - whilst setting modification date");
                            }
                        }
                    }
                    
                    // Set the original permissions on the file
                    uLong permissions = fileInfo.external_fa >> 16;
                    if (permissions != 0) {
                        // Store it into a NSNumber
                        NSNumber *permissionsValue = @(permissions);
                        
                        // Retrieve any existing attributes
                        NSMutableDictionary *attrs = [[NSMutableDictionary alloc] initWithDictionary:[fileManager attributesOfItemAtPath:fullPath error:nil]];
                        
                        // Set the value in the attributes dict
                        attrs[NSFilePosixPermissions] = permissionsValue;
                        
                        // Update attributes
                        if ([fileManager setAttributes:attrs ofItemAtPath:fullPath error:nil] == NO) {
                            // Unable to set the permissions attribute
                            NSLog(@"[SSZipArchive] Failed to set attributes - whilst setting permissions");
                        }
                        
#if !__has_feature(objc_arc)
                        [attrs release];
#endif
                    }
                }
            }
            else
            {
                // Assemble the path for the symbolic link
                NSMutableString* destinationPath = [NSMutableString string];
                int bytesRead = 0;
                while((bytesRead = unzReadCurrentFile(zip, buffer, 4096)) > 0)
                {
                    buffer[bytesRead] = (int)0;
                    [destinationPath appendString:@((const char*)buffer)];
                }
                
                // Create the symbolic link (making sure it stays relative if it was relative before)
                int symlinkError = symlink([destinationPath cStringUsingEncoding:NSUTF8StringEncoding],
                                           [fullPath cStringUsingEncoding:NSUTF8StringEncoding]);
                
                if(symlinkError != 0)
                {
                    NSLog(@"Failed to create symbolic link at \"%@\" to \"%@\". symlink() error code: %d", fullPath, destinationPath, errno);
                }
            }
            
            crc_ret = unzCloseCurrentFile( zip );
            if (crc_ret == UNZ_CRCERROR) {
                //CRC ERROR
                success = NO;
                break;
            }
            ret = unzGoToNextFile( zip );
            
            // Message delegate
            if ([delegate respondsToSelector:@selector(zipArchiveDidUnzipFileAtIndex:totalFiles:archivePath:fileInfo:)]) {
                [delegate zipArchiveDidUnzipFileAtIndex:currentFileNumber totalFiles:(NSInteger)globalInfo.number_entry
                                            archivePath:path fileInfo:fileInfo];
            } else if ([delegate respondsToSelector: @selector(zipArchiveDidUnzipFileAtIndex:totalFiles:archivePath:unzippedFilePath:)]) {
                [delegate zipArchiveDidUnzipFileAtIndex: currentFileNumber totalFiles: (NSInteger)globalInfo.number_entry
                                            archivePath:path unzippedFilePath: fullPath];
            }
            
            currentFileNumber++;
            if (progressHandler)
            {
                progressHandler(strPath, fileInfo, currentFileNumber, globalInfo.number_entry);
            }
        }
    } while(ret == UNZ_OK && ret != UNZ_END_OF_LIST_OF_FILE);
    
    // Close
    unzClose(zip);
    
    // The process of decompressing the .zip archive causes the modification times on the folders
    // to be set to the present time. So, when we are done, they need to be explicitly set.
    // set the modification date on all of the directories.
    NSError * err = nil;
    for (NSDictionary * d in directoriesModificationDates) {
        if (![[NSFileManager defaultManager] setAttributes:@{NSFileModificationDate: d[@"modDate"]} ofItemAtPath:d[@"path"] error:&err]) {
            NSLog(@"[SSZipArchive] Set attributes failed for directory: %@.", d[@"path"]);
        }
        if (err) {
            NSLog(@"[SSZipArchive] Error setting directory file modification date attribute: %@",err.localizedDescription);
        }
    }
    
#if !__has_feature(objc_arc)
    [directoriesModificationDates release];
#endif
    
    // Message delegate
    if (success && [delegate respondsToSelector:@selector(zipArchiveDidUnzipArchiveAtPath:zipInfo:unzippedPath:)]) {
        [delegate zipArchiveDidUnzipArchiveAtPath:path zipInfo:globalInfo unzippedPath:destination];
    }
    // final progress event = 100%
    if (!canceled && [delegate respondsToSelector:@selector(zipArchiveProgressEvent:total:)]) {
        [delegate zipArchiveProgressEvent:fileSize total:fileSize];
    }
    
    NSError *retErr = nil;
    if (crc_ret == UNZ_CRCERROR)
    {
        NSDictionary *userInfo = @{NSLocalizedDescriptionKey: @"crc check failed for file"};
        retErr = [NSError errorWithDomain:@"SSZipArchiveErrorDomain" code:-3 userInfo:userInfo];
    }
    if (error)
    {
        *error = retErr;
    }
    if (completionHandler)
    {
        completionHandler(path, success, retErr);
    }
    return success;
}

#pragma mark - Zipping
+ (BOOL)createZipFileAtPath:(NSString *)path withFilesAtPaths:(NSArray *)paths
{
    return [SSZipArchive createZipFileAtPath:path withFilesAtPaths:paths withPassword:nil];
}
+ (BOOL)createZipFileAtPath:(NSString *)path withContentsOfDirectory:(NSString *)directoryPath{
    return [SSZipArchive createZipFileAtPath:path withContentsOfDirectory:directoryPath withPassword:nil];
}

+ (BOOL)createZipFileAtPath:(NSString *)path withContentsOfDirectory:(NSString *)directoryPath keepParentDirectory:(BOOL)keepParentDirector{
    return [SSZipArchive createZipFileAtPath:path withContentsOfDirectory:directoryPath keepParentDirectory:keepParentDirector withPassword:nil];
}

+ (BOOL)createZipFileAtPath:(NSString *)path withFilesAtPaths:(NSArray *)paths withPassword:(NSString *)password
{
    BOOL success = NO;
    SSZipArchive *zipArchive = [[SSZipArchive alloc] initWithPath:path];
    if ([zipArchive open]) {
        for (NSString *filePath in paths) {
            [zipArchive writeFile:filePath withPassword:password];
        }
        success = [zipArchive close];
    }
    
#if !__has_feature(objc_arc)
    [zipArchive release];
#endif
    
    return success;
}

+ (BOOL)createZipFileAtPath:(NSString *)path withContentsOfDirectory:(NSString *)directoryPath  withPassword:(NSString *)password{
    return [self createZipFileAtPath:path withContentsOfDirectory:directoryPath keepParentDirectory:NO withPassword:password];
}


+ (BOOL)createZipFileAtPath:(NSString *)path withContentsOfDirectory:(NSString *)directoryPath keepParentDirectory:(BOOL)keepParentDirectory withPassword:(NSString *)password{
    BOOL success = NO;
    
    NSFileManager *fileManager = nil;
    SSZipArchive *zipArchive = [[SSZipArchive alloc] initWithPath:path];
    
    if ([zipArchive open]) {
        // use a local filemanager (queue/thread compatibility)
        fileManager = [[NSFileManager alloc] init];
        NSDirectoryEnumerator *dirEnumerator = [fileManager enumeratorAtPath:directoryPath];
        NSString *fileName;
        while ((fileName = [dirEnumerator nextObject])) {
            BOOL isDir;
            NSString *fullFilePath = [directoryPath stringByAppendingPathComponent:fileName];
            [fileManager fileExistsAtPath:fullFilePath isDirectory:&isDir];
            if (!isDir) {
                if (keepParentDirectory)
                {
                    fileName = [[directoryPath lastPathComponent] stringByAppendingPathComponent:fileName];
                }
                [zipArchive writeFileAtPath:fullFilePath withFileName:fileName withPassword:password];
            }
            else
            {
                if([[NSFileManager defaultManager] subpathsOfDirectoryAtPath:fullFilePath error:nil].count == 0)
                {
                    NSString *tempName = [fullFilePath stringByAppendingPathComponent:@".DS_Store"];
                    [@"" writeToFile:tempName atomically:YES encoding:NSUTF8StringEncoding error:nil];
                    [zipArchive writeFileAtPath:tempName withFileName:[fileName stringByAppendingPathComponent:@".DS_Store"] withPassword:password];
                    [[NSFileManager defaultManager] removeItemAtPath:tempName error:nil];
                }
            }
        }
        success = [zipArchive close];
    }
    
#if !__has_feature(objc_arc)
    [fileManager release];
    [zipArchive release];
#endif
    
    return success;
}


- (instancetype)initWithPath:(NSString *)path
{
    if ((self = [super init])) {
        _path = [path copy];
    }
    return self;
}


#if !__has_feature(objc_arc)
- (void)dealloc
{
    [_path release];
    [super dealloc];
}
#endif


- (BOOL)open
{
    NSAssert((_zip == NULL), @"Attempting open an archive which is already open");
    _zip = zipOpen([_path UTF8String], APPEND_STATUS_CREATE);
    return (NULL != _zip);
}


- (void)zipInfo:(zip_fileinfo*)zipInfo setDate:(NSDate*)date
{
    NSCalendar *currentCalendar = [NSCalendar currentCalendar];
#if defined(__IPHONE_8_0) || defined(__MAC_10_10)
    uint flags = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
#else
    uint flags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
#endif
    NSDateComponents *components = [currentCalendar components:flags fromDate:date];
    zipInfo->tmz_date.tm_sec = (unsigned int)components.second;
    zipInfo->tmz_date.tm_min = (unsigned int)components.minute;
    zipInfo->tmz_date.tm_hour = (unsigned int)components.hour;
    zipInfo->tmz_date.tm_mday = (unsigned int)components.day;
    zipInfo->tmz_date.tm_mon = (unsigned int)components.month - 1;
    zipInfo->tmz_date.tm_year = (unsigned int)components.year;
}

- (BOOL)writeFolderAtPath:(NSString *)path withFolderName:(NSString *)folderName withPassword:(NSString *)password
{
    NSAssert((_zip != NULL), @"Attempting to write to an archive which was never opened");
    
    zip_fileinfo zipInfo = {{0}};
    
    NSDictionary *attr = [[NSFileManager defaultManager] attributesOfItemAtPath:path error: nil];
    if( attr )
    {
        NSDate *fileDate = (NSDate *)attr[NSFileModificationDate];
        if( fileDate )
        {
            [self zipInfo:&zipInfo setDate: fileDate ];
        }
        
        // Write permissions into the external attributes, for details on this see here: http://unix.stackexchange.com/a/14727
        // Get the permissions value from the files attributes
        NSNumber *permissionsValue = (NSNumber *)attr[NSFilePosixPermissions];
        if (permissionsValue) {
            // Get the short value for the permissions
            short permissionsShort = permissionsValue.shortValue;
            
            // Convert this into an octal by adding 010000, 010000 being the flag for a regular file
            NSInteger permissionsOctal = 0100000 + permissionsShort;
            
            // Convert this into a long value
            uLong permissionsLong = @(permissionsOctal).unsignedLongValue;
            
            // Store this into the external file attributes once it has been shifted 16 places left to form part of the second from last byte
            zipInfo.external_fa = permissionsLong << 16L;
        }
    }
    
    unsigned int len = 0;
    zipOpenNewFileInZip3(_zip, [[folderName stringByAppendingString:@"/"] UTF8String], &zipInfo, NULL, 0, NULL, 0, NULL, Z_DEFLATED, Z_NO_COMPRESSION, 0, -MAX_WBITS, DEF_MEM_LEVEL,
                         Z_DEFAULT_STRATEGY, [password UTF8String], 0);
    zipWriteInFileInZip(_zip, &len, 0);
    zipCloseFileInZip(_zip);
    return YES;
}

- (BOOL)writeFile:(NSString *)path withPassword:(NSString *)password;
{
    return [self writeFileAtPath:path withFileName:nil withPassword:password];
}

// supports writing files with logical folder/directory structure
// *path* is the absolute path of the file that will be compressed
// *fileName* is the relative name of the file how it is stored within the zip e.g. /folder/subfolder/text1.txt
- (BOOL)writeFileAtPath:(NSString *)path withFileName:(NSString *)fileName withPassword:(NSString *)password
{
    NSAssert((_zip != NULL), @"Attempting to write to an archive which was never opened");
    
    FILE *input = fopen([path UTF8String], "r");
    if (NULL == input) {
        return NO;
    }
    
    const char *afileName;
    if (!fileName) {
        afileName = [path.lastPathComponent UTF8String];
    }
    else {
        afileName = [fileName UTF8String];
    }
    
    zip_fileinfo zipInfo = {{0}};
    
    NSDictionary *attr = [[NSFileManager defaultManager] attributesOfItemAtPath:path error: nil];
    if( attr )
    {
        NSDate *fileDate = (NSDate *)attr[NSFileModificationDate];
        if( fileDate )
        {
            [self zipInfo:&zipInfo setDate: fileDate ];
        }
        
        // Write permissions into the external attributes, for details on this see here: http://unix.stackexchange.com/a/14727
        // Get the permissions value from the files attributes
        NSNumber *permissionsValue = (NSNumber *)attr[NSFilePosixPermissions];
        if (permissionsValue) {
            // Get the short value for the permissions
            short permissionsShort = permissionsValue.shortValue;
            
            // Convert this into an octal by adding 010000, 010000 being the flag for a regular file
            NSInteger permissionsOctal = 0100000 + permissionsShort;
            
            // Convert this into a long value
            uLong permissionsLong = @(permissionsOctal).unsignedLongValue;
            
            // Store this into the external file attributes once it has been shifted 16 places left to form part of the second from last byte
            zipInfo.external_fa = permissionsLong << 16L;
        }
    }
    
    void *buffer = malloc(CHUNK);
    if (buffer == NULL)
    {
        return NO;
    }

    zipOpenNewFileInZip3(_zip, afileName, &zipInfo, NULL, 0, NULL, 0, NULL, Z_DEFLATED, Z_DEFAULT_COMPRESSION, 0, -MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY, [password UTF8String], 0);
    unsigned int len = 0;
    
    while (!feof(input))
    {
        len = (unsigned int) fread(buffer, 1, CHUNK, input);
        zipWriteInFileInZip(_zip, buffer, len);
    }
    
    zipCloseFileInZip(_zip);
    free(buffer);
    fclose(input);
    return YES;
}

- (BOOL)writeData:(NSData *)data filename:(NSString *)filename withPassword:(NSString *)password;
{
    if (!_zip) {
        return NO;
    }
    if (!data) {
        return NO;
    }
    zip_fileinfo zipInfo = {{0,0,0,0,0,0},0,0,0};
    [self zipInfo:&zipInfo setDate:[NSDate date]];
    
    zipOpenNewFileInZip3(_zip, [filename UTF8String], &zipInfo, NULL, 0, NULL, 0, NULL, Z_DEFLATED, Z_DEFAULT_COMPRESSION, 0, -MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY, [password UTF8String], 0);
    
    zipWriteInFileInZip(_zip, data.bytes, (unsigned int)data.length);
    
    zipCloseFileInZip(_zip);
    return YES;
}


- (BOOL)close
{
    NSAssert((_zip != NULL), @"[SSZipArchive] Attempting to close an archive which was never opened");
    zipClose(_zip, NULL);
    return YES;
}

#pragma mark - Private

// Format from http://newsgroups.derkeiler.com/Archive/Comp/comp.os.msdos.programmer/2009-04/msg00060.html
// Two consecutive words, or a longword, YYYYYYYMMMMDDDDD hhhhhmmmmmmsssss
// YYYYYYY is years from 1980 = 0
// sssss is (seconds/2).
//
// 3658 = 0011 0110 0101 1000 = 0011011 0010 11000 = 27 2 24 = 2007-02-24
// 7423 = 0111 0100 0010 0011 - 01110 100001 00011 = 14 33 3 = 14:33:06
+ (NSDate *)_dateWithMSDOSFormat:(UInt32)msdosDateTime
{
    static const UInt32 kYearMask = 0xFE000000;
    static const UInt32 kMonthMask = 0x1E00000;
    static const UInt32 kDayMask = 0x1F0000;
    static const UInt32 kHourMask = 0xF800;
    static const UInt32 kMinuteMask = 0x7E0;
    static const UInt32 kSecondMask = 0x1F;
    
    static NSCalendar *gregorian;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
#if defined(__IPHONE_8_0) || defined(__MAC_10_10)
        gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
#else
        gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
#endif
    });
    
    NSDateComponents *components = [[NSDateComponents alloc] init];
    
    NSAssert(0xFFFFFFFF == (kYearMask | kMonthMask | kDayMask | kHourMask | kMinuteMask | kSecondMask), @"[SSZipArchive] MSDOS date masks don't add up");
    
    [components setYear:1980 + ((msdosDateTime & kYearMask) >> 25)];
    [components setMonth:(msdosDateTime & kMonthMask) >> 21];
    [components setDay:(msdosDateTime & kDayMask) >> 16];
    [components setHour:(msdosDateTime & kHourMask) >> 11];
    [components setMinute:(msdosDateTime & kMinuteMask) >> 5];
    [components setSecond:(msdosDateTime & kSecondMask) * 2];
    
    NSDate *date = [NSDate dateWithTimeInterval:0 sinceDate:[gregorian dateFromComponents:components]];
    
#if !__has_feature(objc_arc)
    [components release];
#endif
    
    return date;
}

@end