There’s a spec at the w3c about compressing (XML) named “Efficient XML Interchange” Format taking into account the grammar and likelihood of atoms within the document. They indeed use something similar the the Huffman Coding.
The results are quite impressive – nice charts!
Jan 29
klick ich den Link, den T-Mobile mir per SMS geschickt hat, kriege ich:
T-Mobile Scherz
as the iPhone SDK comes with a rather dysfunctional NSURLCache — Apple suggests to implement it from scratch yourself in the code examples about caching — I went for just this.
Until I came across the [NSKeyedUnarchiver unarchiveObjectWithData:...] not restoring userInfo, storagePolicy and data of NSCachedURLResponse.
Couldn’t believe it and spent almost the whole day verifying that the error is not within my code but really the unarchiver treats those fields transient.
See yourself:
-(void)testiPhoneSDK312NSKeyedArchiver { // prepare a NSCachedURLResponse NSCachedURLResponse *src = nil; { NSURL *i_url = [NSURL URLWithString:@"http://www.url.example/path/file.html"]; NSString *i_mime = @"text/html"; NSInteger expectedContentLength = 112; NSString *i_encoding = @"iso-8859-2"; NSURLResponse *i_response = [[NSURLResponse alloc] initWithURL:i_url MIMEType:i_mime expectedContentLength:expectedContentLength textEncodingName:i_encoding]; NSData *i_data = [@"Hello, world!" dataUsingEncoding:NSISOLatin2StringEncoding]; NSURLCacheStoragePolicy i_storage = NSURLCacheStorageAllowed; NSDictionary *i_userInfo = [NSDictionary dictionaryWithObject: [NSDate dateWithTimeIntervalSince1970:13] forKey:@"era"]; NSCachedURLResponse *src = [[NSCachedURLResponse alloc] initWithResponse:i_response data:i_data userInfo:i_userInfo storagePolicy:i_storage]; // ensure it's all in place: STAssertEqualObjects(i_url, src.response.URL, @""); STAssertEqualObjects(i_mime, src.response.MIMEType, @""); STAssertEquals((int)expectedContentLength, (int)src.response.expectedContentLength, @""); STAssertEqualObjects(@"file.html", src.response.suggestedFilename, @""); STAssertEqualObjects(i_encoding, src.response.textEncodingName, @""); STAssertEqualObjects(i_data, src.data, @""); STAssertEqualObjects(i_userInfo, src.userInfo, @""); STAssertEquals( 0u, src.storagePolicy, @""); } // archive + unarchive: NSCachedURLResponse *dst = [NSKeyedUnarchiver unarchiveObjectWithData: [NSKeyedArchiver archivedDataWithRootObject:src]]; // check whether src == dst STAssertEqualObjects(src.response.URL, dst.response.URL, @""); STAssertEqualObjects(src.response.MIMEType, dst.response.MIMEType, @""); STAssertEquals(src.response.expectedContentLength, dst.response.expectedContentLength, @""); STAssertEqualObjects(src.response.suggestedFilename, dst.response.suggestedFilename, @""); STAssertEqualObjects(src.response.textEncodingName, dst.response.textEncodingName, @""); // !!!!!!!!!! // sad information loss after unarchiving: STAssertNil( dst.data, @"" ); STAssertNil( dst.userInfo, @"" ); STAssertEquals( 2u , dst.storagePolicy, @"" ); }
When my NSURLCache replacement is ready I think about publishing it a github — interested anyone?
Jan 13
Though CFArray comes with binary search capability, NSArray does not – at least not within the iPhone SDK. The indexOfObject:inSortedRange:options:usingComparator: can’t be found.
Plus the CFArrayBSearchValues doesn’t tell you whether the key actually is part of the list or not. That’s what the Java JDK does, so let’s implement some category methods
-(NSInteger)binarySearch:(id)key; -(NSInteger)binarySearch:(id)key usingSelector:(SEL)comparator; -(NSInteger)binarySearch:(id)key usingSelector:(SEL)comparator inRange:(NSRange)range; -(NSInteger)binarySearch:(id)key usingFunction:(NSInteger (*)(id, id, void *))comparator context:(void *)context; -(NSInteger)binarySearch:(id)key usingFunction:(NSInteger (*)(id, id, void *))comparator context:(void *)context inRange:(NSRange)range; -(NSInteger)binarySearch:(id)key usingDescriptors:(NSArray *)sortDescriptors; -(NSInteger)binarySearch:(id)key usingDescriptors:(NSArray *)sortDescriptors inRange:(NSRange)range;
ourselves, like
-(NSInteger)binarySearch:(id)key usingFunction:(NSInteger (*)(id, id, void *))comparator context:(void *)context inRange:(NSRange)range { NSLogD(@"[NSArray(MroBinarySearch) binarySearch:%@ usingFunction:]", key); if(self.count == 0 || key == nil || comparator == NULL) return [self binarySearch:key usingSelector:nil inRange:range]; // check overflow? NSInteger min = range.location; NSInteger max = range.location + range.length - 1; while (min < = max) { // http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html const NSInteger mid = min + (max - min) / 2; switch (comparator(key, [self objectAtIndex:mid], context)) { case NSOrderedSame: return mid; case NSOrderedDescending: min = mid + 1; break; case NSOrderedAscending: max = mid - 1; break; } } return -(min + 1); }
See the full interface + implementation + testcase without html encoding dirt at github.
Jan 7
Weil große Email Anhänge stinken, bietet sich z.B. die Dropbox als Dateiaustauschplatform an.
Einfach die Datei in den (lokalen) Dropbox/Public Ordner verfrachten, syncen lassen und per “Rechte Maustaste -> Copy Public Link” in die Mail kopieren.
Nun sind solche Links nicht besonders hübsch (Branding!, Branding!, CI! ruft die Marketingabteilung) und spätestens wenn man’s abtippen muß oder per Telephon weitersagt wird’s gruslig.
Hat man aber eine eigene Website, lassen sich die Dropbox Links aufhübschen und eine Weiterleitung einrichten, dann wird aus
http://dl.dropbox.com/u/1234567/BigDocument.pdf
z.B.
http://dropbox.mydomain.com/BigDocument.pdf
und schon sind die Brandingfreunde happy.
Geht es nicht um eine einzelne Datei sondern um mehrere, will man evtl. eine Übersicht in einer index.html haben. So eine Übersicht legt z.B. mein ruby Script htmlizedb an. Das Script will im Terminal in dem Verzeichnis gestartet werden, für das die Übersicht her soll.
Bei Webservern ist allgemein üblich, daß man den Dateinamen index.html im Link weglassen kann. Der Webserver nimmt dann an man meint selbige. Die Dropbox verhält sich aber in dieser Hinsicht nicht wie ein normaler Webserver, sondern will immer den kompletten Dateinamen.
Hat man aber bereits den Redirect Trick in Benutzung, läßt sich die Redirect Steuerdatei (.htaccess) aufbohren, daß der Redirect die index.html Angabe ergänzt:
RewriteEngine on # dropbox abbreviation: # http://www.cimitan.com/blog/2008/09/17/htaccess-to-redirect-on-dropboxs-public-folder/# # last path component has no dot -> redirect to index.html RewriteRule ^(.+/)?([^./]+)/?$ http://dl.dropbox.com/u/1234567/$1$2/index.html [last,qsappend] # everything else: redirect as is RewriteRule ^(.+)$ http://dl.dropbox.com/u/1234567/$1 [last,qsappend]
violá, nun wird von
http://dropbox.mydomain.com/FolderWithBigFiles
automatisch auf den Dropbox Link
http://dl.dropbox.com/u/1234567/FolderWithBigFiles/index.html
weitergeleitet.
Toll, nicht?
Dez 30
Seit längerem schneide ich mir interessante Sendungen aus dem (Internet-)Radio mit, vor allem Hörspiele auf B2.
Bisher mußte dazu immer mein alter (Linux-)Rechner laufen und den Mitschnitt mußte ich händisch starten – wie unbequem. Oder man ist unterwegs und verpaßt den Mitschnitt. Wie ärgerlich.
Doch das ist ab jetzt vorbei, denn ab sofort schneidet mein vServer (läuft ja eh ständig) mit!
Und so geht’s:
#!/bin/sh # id3v2 scheint Bilder nicht zu mögen: # - http://ubuntuforums.org/showthread.php?t=1353213 # - readonly: http://id3v2.cvs.sourceforge.net/viewvc/id3v2/id3v2/id3v2.cpp?revision=1.17&view=markup#l_610 # - http://www.id3.org/id3v2.4.0-frames Kapitel4.14. # erfolglos: id3v2 --APIC "0\0image/jpeg\03hello\0`cat moby_dick.jpg`" $file if [ $# -lt 3 ]; then echo "rip audio streams to a local file." echo " " echo "Usage:" echo " " echo " $0 stream marker duration id3v2_tags" echo " stream typically a URL, see 'man streamripper'" echo " marker filename prefix" echo " seconds how long will we dump" echo " id3v2_tags optional, tag the download with id3v2" echo " " echo "Example:" echo " $0 http://gffstream.ic.llnwd.net/stream/gffstream_w11a bayern2 3660" echo " " exit 1 fi src=$1 ; shift basename=$1 ; shift seconds=$1 ; shift dst=$basename-`date --iso-8601=seconds` echo "dumping $seconds (sec) from $src to $dst ..." streamripper $src -u Mozilla -i -a $dst -l $seconds rm $dst.cue if [ $# -gt 0 ] ; then id3v2 "$@" $dst.mp3 fi chmod a+r $dst.* echo done.
PATH=/bin:/usr/bin HOME=/home/USERNAME # Recorder rec_cmd=/home/USERNAME/bin/stream-rip rec_dir=/home/USERNAME/pub/recorder ON3=http://gffstream.ic.llnwd.net/stream/gffstream_w9a BAYERN1=http://gffstream.ic.llnwd.net/stream/gffstream_w10a BAYERN2=http://gffstream.ic.llnwd.net/stream/gffstream_w11a M945=http://stream.m945.mwn.de:80/m945-hq.mp3 # B2 Krimihörspiel 29 20 * * 3 $rec_cmd $BAYERN2 $rec_dir/b2-krimi 3660 -A "B2 Krimi"
After upgrading to Snow Leopard and XCode 3.2.1 I’ve seen such console output
CAUnderRetain(32139,0xa0391500) malloc: *** error for object 0x3838000: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug
when rotating the iPhone Simulator in a project with base SDK 3.0.
This can be reproduced as follows:
Fresh Navigation based App + CoreData
// Override to allow orientations other than the default portrait orientation. - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { // Return YES for supported orientations. return YES; } -(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration { NSLog(@"willRotateToInterfaceOrientation"); }
to the RootViewConroller.m
Base SDk 3.0
Simulator 3.1.2 rotates fine
Simulator 3.0 underretain
[Session started at 2009-12-12 21:49:31 +0100.] GNU gdb 6.3.50-20050815 (Apple version gdb-1346) (Fri Sep 18 20:40:51 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "x86_64-apple-darwin".sharedlibrary apply-load-rules all Attaching to process 32139. 2009-12-12 21:49:43.845 CAUnderRetain[32139:207] willRotateToInterfaceOrientation CAUnderRetain(32139,0xa0391500) malloc: *** error for object 0x1853000: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug CAUnderRetain(32139,0xa0391500) malloc: *** error for object 0x3824000: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug warning: Unable to restore previously selected frame. warning: Couldn't find minimal bounds for "_sigtramp" - backtraces may be unreliable (gdb) break malloc_error_break Breakpoint 1 at 0x92626072 (gdb) continue 2009-12-12 21:49:58.490 CAUnderRetain[32139:207] willRotateToInterfaceOrientation CAUnderRetain(32139,0xa0391500) malloc: *** error for object 0x3838000: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug Unable to disassemble malloc_error_break. (gdb) bt #0 0x92626072 in malloc_error_break () #1 0x92535303 in free () #2 0x0015ce49 in dataReleaseInfo () #3 0x001481d9 in data_provider_finalize () #4 0x30204421 in _CFRelease () #5 0x00147fa2 in image_finalize () #6 0x30204421 in _CFRelease () #7 0x00c12ded in CALayerStateRelease () #8 0x00c18290 in -[CALayer dealloc] () #9 0x00c0a00e in CALayerRelease () #10 0x00c0b265 in CA::release_root_if_unused () #11 0x00c0b1ef in x_hash_table_remove_if () #12 0x00c0afd4 in CA::Transaction::commit () #13 0x00c132e0 in CA::Transaction::observer_callback () #14 0x30245c32 in __CFRunLoopDoObservers () #15 0x3024503f in CFRunLoopRunSpecific () #16 0x30244628 in CFRunLoopRunInMode () #17 0x32044c31 in GSEventRunModal () #18 0x32044cf6 in GSEventRun () #19 0x309021ee in UIApplicationMain () #20 0x00002018 in main (argc=1, argv=0xbfffea84) at /Users/.../CAUnderRetain/main.m:14 (gdb)
The base for many of my SELECT-ish queries when querying by exact match is one generic method I created in some category methods on NSManagedObjectContext:
-(NSArray*)entityName:(NSString*)entityName findManyByRelation:(NSDictionary*)dict { // TODO handle dict nil and emptyness NSMutableArray *arr = [[NSMutableArray alloc] initWithCapacity:dict.count]; for(NSString *key in dict) { NSExpression *left = [NSExpression expressionForKeyPath:key]; NSExpression *right = [NSExpression expressionForConstantValue:[dict objectForKey:key]]; NSComparisonPredicate *cp = [[NSComparisonPredicate alloc] initWithLeftExpression:left rightExpression:right modifier:NSDirectPredicateModifier type:NSEqualToPredicateOperatorType options:0]; [arr addObject:cp]; [cp release]; } NSPredicate *pred = nil; if(arr.count == 1) pred = [[arr objectAtIndex:0] retain]; // why do I have to retain here? else pred = [[NSCompoundPredicate alloc] initWithType:NSAndPredicateType subpredicates:arr]; NSFetchRequest *fr = [[NSFetchRequest alloc] init]; fr.entity = [NSEntityDescription entityForName:entityName inManagedObjectContext:self]; fr.predicate = pred; [arr release]; [pred release]; // NSLog(@"predicate effective: %@", fr.predicate); NSError *err = nil; NSArray *ps = [self executeFetchRequest:fr error:&err]; if(err != nil) [NSException raise:@"DB Error" format:@"Fetch problem %@", fr.predicate.predicateFormat]; [fr release]; return ps; }
For example it serves under the hood of it’s sibling helpers
-(NSManagedObject*)entityName:(NSString*)entityName findByPrimaryKey:(NSDictionary*)dict { NSArray *ps = [self entityName:entityName findManyByRelation:dict]; if(ps == nil || ps.count == 0) return nil; if (ps.count == 1) return [ps objectAtIndex:0]; [NSException raise:@"DB Error" format:@"Multiple hits for %@", dict]; return (NSManagedObject*)1/0; }
and
-(NSManagedObject*)entityName:(NSString*)entityName selectOrInsertWithKey:(NSDictionary*)dict { NSManagedObject *o = [self entityName:entityName findByPrimaryKey:dict]; if(o == nil) { NSEntityDescription *ed = [NSEntityDescription entityForName:entityName inManagedObjectContext:self]; o = [[NSManagedObject alloc] initWithEntity:ed insertIntoManagedObjectContext:self]; for(NSString *key in dict) [o setValue:[dict objectForKey:key] forKey:key]; [o autorelease]; } return o; }
Those methods again are called by custom convenience wrappers in the model classes loosely following the ActiveRecord Pattern.
Von wegen Schock beim Logout – mich lassen sie gar nicht erst rein:
Though NSDateFormatter behaves slightly different than documented, the following might even be correct, as strange as it might look (mind the last two lines):
-(void)testNSDateFormatterTrap { NSDateFormatter *lower = [[[NSDateFormatter alloc] init] autorelease]; lower.dateFormat = @"yyyy-MM-dd HH:mm:SS ZZZ"; NSDateFormatter *upper = [[[NSDateFormatter alloc] init] autorelease]; upper.dateFormat = @"YYYY-MM-dd HH:mm:SS ZZZ"; lower.timeZone = upper.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:0]; NSDate *d = [lower dateFromString:@"1970-01-01 00:00:00 +0000"]; STAssertEqualObjects(@"1970-01-01 00:00:00 +0000", [lower stringFromDate:d], @"lower iso wrong"); STAssertEqualObjects(@"1970-01-01 00:00:00 +0000", [upper stringFromDate:d], @"upper iso wrong"); d = [d addTimeInterval:(-60*60)]; STAssertEqualObjects(@"1969-12-31 23:00:00 +0000", [lower stringFromDate:d], @"lower iso wrong"); STAssertEqualObjects(@"1970-12-31 23:00:00 +0000", [upper stringFromDate:d], @"upper iso wrong"); }
The Unicode Format Pattern Documentation explains the difference of the upper- and lowercase year format – but frankly I don’t get the “Year of week of year” idea.
But that subtracting one hour in fact adds almost a whole year – that’s odd to me.
So I rather stay away from the uppercase form – be it correct or buggy.
Seen with iPhone SDK 3.1.2 and XCode 3.2.1 on Snow Leopard.
Update:
I think I got it! Uppercase YYYY makes sense only in combination with a calendar week – and not months or quarters.
Look at January 1st 2010. It belongs to calendar week 53 of 2009. Week 1/2010 starts on Jan 4th.