Archive for November 6, 2018

Tuesday, November 6, 2018 [Tweets] [Favorites]

String’s ABI and UTF-8

Michael Ilseman:

We just landed String’s proposed final ABI on master. This ABI includes some significant changes, the primary one being that native Swift strings are stored as UTF-8 where they were previously stored either as ASCII or UTF-16 depending on their contents.


Unifying the storage representation for ASCII and Unicode-rich strings gives us a lot of performance wins. These wins are an effect of several compounding factors including a simpler model with less branching, on-creation encoding validation of native Strings (enabled by a faster validator), a unified implementation code path, a more efficient allocation and use of various bits in the struct, etc.


By maintaining nul-termination in our storage, interoperability with C is basically free: we just use our pointer.


Efficient interoperability with Cocoa is a huge selling point for Swift, and strings are lazily bridged to Objective-C. String’s storage class is a subclass of NSString at runtime, and thus has to answer APIs assuming constant-time access to UTF-16 code units. We solved this with a breadcrumbing strategy: upon first request from one of these APIs on large strings, we perform a fast scan of the contents to check the UTF-16 length, leaving behind breadcrumbs at regular intervals. This allows us to provide amortized constant-time access to transcoded UTF-16 contents by scanning between breadcrumbs.


The branch also introduces support in the ABI (but currently not exposed in any APIs) for shared strings, which provide contiguous UTF-8 code units through some externally-managed storage. These enable future APIs allowing developers to create a String with shared storage from a [UInt8], Data, ByteBuffer, or Substring without actually copying the contents.

This sounds great. Here is the pull request and the implementation of StringObject (which is actually a struct). Note that this locks in the in-memory layout for Swift strings, because code that uses them may be inlined. In contrast, Cocoa’s NSString has an internal representation that has evolved over time. This was possible because access was indirected through the Objective-C runtime.

Previously: Swift String ABI, Performance, and Ergonomics, Swift ABI Stability Dashboard.

Update (2018-11-07): See this pull request from David Smith about improving performance for bridged strings (tweet).

Update (2018-11-09): See also: Hacker News.

Flickr to Limit Free Accounts to 1,000 Photos

Andrew Stadlen:

Beginning January 8, 2019, Free accounts will be limited to 1,000 photos and videos. If you need unlimited storage, you’ll need to upgrade to Flickr Pro.

In 2013, Yahoo lost sight of what makes Flickr truly special and responded to a changing landscape in online photo sharing by giving every Flickr user a staggering terabyte of free storage. This, and numerous related changes to the Flickr product during that time, had strongly negative consequences.

First, and most crucially, the free terabyte largely attracted members who were drawn by the free storage, not by engagement with other lovers of photography.


Giving away vast amounts of storage creates data that can be sold to advertisers, with the inevitable result being that advertisers’ interests are prioritized over yours. Reducing the free storage offering ensures that we run Flickr on subscriptions, which guarantees that our focus is always on how to make your experience better.

Don MacAskill:

Actually, more than 97% of @Flickr Free accounts are under 1,000 photos. The changes we announced today are mostly about enhancing Flickr Pro. Less than 3% of Flickr Free accounts, who chew up a huge amount of storage & costs that others must bear, are asked to make a decision.

This makes sense except that:

A. Lee Bennett Jr.:

All the people complaining of the @Flickr changes and are leaving are probably the ones that will make Flickr a better community when they leave.

Hope y’all enjoy Google Photos’ compression and watching your original/uncompressed photos disappear.

Previously: SmugMug Acquires Flickr.

Update (2018-11-08): Don MacAskill:

The Flickr Commons photos (those uploaded by the archival, governmental, etc. institutions we are working with) are safe. We are extremely proud of these partnerships. These photos won’t be deleted as a result of any of our announced changes. The only reason they’d disappear is if the organization that uploaded them decided to delete them.

Photos that were Creative Commons licensed before our announcement are also safe. We won’t be deleting anything that was uploaded with a CC license before November 1, 2018. Even if you had more than 1,000 photos or videos with a CC license.

Update (2018-11-13): Glenn Fleishman:

Do you know someone who died and their Flickr account remains at free tier, and they have > 1,000 photos and videos? I’d suggest contacting their family, and then contacting Flickr. In an interview with SmugMug head Don MacAskill he said several people raised the notion of accounts of deceased people losing images, but on asking, he as of a few days ago hadn’t been given any actual account names.

Nick Heer:

Pretty wild that this Flickr email announcing that they’ll be deleting some of my photos in three months buries that rather critical detail in small grey text near the bottom.

Apple’s New Map

Justin O’Beirne:

If RMSI is creating Apple’s buildings by manually tracing them from satellite imagery, it would explain how Apple’s building perimeters could be more precise than Google’s algorithmically-generated buildings:


Regardless of how Apple is creating all of its buildings and other shapes, Apple is filling its map with so many of them that Google now looks empty in comparison[…] And all of these details create the impression that Apple hasn’t just closed the gap with Google—but has, in many ways, exceeded it...

...but only within the 3.1% of the U.S. where the new map is currently live.


In other words, TomTom’s database somehow has roads from Parkfield’s boomtown days—roads that have been gone for more than 75 years. No wonder why Apple removed them.


Unless they’re already listed on Yelp, none of the shapes Apple has added appear in its search results or are labeled on its map. And this is a problem for Apple because AR is all about labels—but Apple’s new map is all about shapes.

So is Apple making the right map?

James O’Leary:

Apple: “We don’t think there’s anybody doing this level of work that we’re doing.”

TechCrunch: “wow lemme write that”

Ex-Apple Maps, politely: you offshored maps to 5,000 doing manual work. after 5yrs, you have vegetation for 3.1% of the US +bad place data

John Gruber:

O’Beirne’s keen observation is this: even in the areas where Apple’s new maps have rolled out, Google is still far ahead in correctly identifying places and specific destinations.

Nick Heer:

Rebuilding Maps in such a comprehensive way is going to take some time, so I read O’Beirne’s analysis as a progress report. But, even keeping that in mind, it’s a little disappointing that what has seemingly been prioritized so far in this Maps update is to add more detailed shapes for terrain and foliage, rather than fixing what places are mapped and where they’re located. It

Rui Carmo:

At this rate, we are never going to be able to use Apple Maps in Europe.

Although Apple Maps have improved markedly (and worked OK during my recent trip to Edinburgh) there are still loads of things missing (landmarks, streets, transit info), and have stayed that way for years, whereas Google Maps are sometimes corrected within days.

Previously: Rebuilding Apple Maps Using Apple’s Own Data, Google Maps’s Moat.

Update (2018-11-09): See also: Hacker News.