Yes: API consistency. An ArrayBuffer is opaque; to work with the data it contains, instantiate a view.
On Tue, Apr 2, 2013 at 3:36 PM, Kevin Gadd <kevin.g...@gmail.com> wrote: > Is there a reason why DataView wasn't specified as static methods that take > an ArrayBuffer in the first place? That would solve the problem of figuring > out when/how often to create DataView instances, and eliminate the garbage > created by using DataViews. > > > On Tue, Apr 2, 2013 at 3:23 PM, Kenneth Russell <k...@google.com> wrote: >> >> On Tue, Apr 2, 2013 at 3:03 PM, Aymeric Vitte <vitteayme...@gmail.com> >> wrote: >> > >> > Le 02/04/2013 04:24, Kenneth Russell a écrit : >> >> >> >> Agreed. DataView's methods are all simple and should be easy to >> >> optimize. Because they include a conditional byte swap, they can't run >> >> quite as fast as the typed arrays' accessors -- but they shouldn't >> >> need to. DataView was designed to support file and network I/O, where >> >> throughput is limited by the disk or network connection. The typed >> >> array views were designed for in-memory assembly of data to be >> >> submitted to the graphics card, sound card, etc., and must run as fast >> >> as possible. >> > >> > When you are streaming things, what's the correct use of DataViews? >> > >> > ie : you are supposed to create each time you want to read some bytes a >> > DataView (which can be optimized or whatever, but still with some >> > costs)? >> > >> > Maybe it's outside of the scope of this discussion, I have already >> > provided >> > examples, I still suspect that I am using it wrongly or that >> > ArrayBuffers >> > are more adapted to webgl (ie static buffer manipulation) than network >> > streaming (ie dynamic buffer manipulation). >> > >> > Probably I am wrong but really would like to know then what's the >> > correct >> > use. >> >> If I understand your question, then the correct use of DataView is: >> upon receiving an ArrayBuffer, create a DataView referring to it. When >> iterating down the contents of the ArrayBuffer, continue to use the >> same DataView instance, just incrementing the offset. In >> abstract-tls/lib/abstract-tls.js there are some operations which >> create a new DataView just to read or write a single element; this >> isn't the correct usage. >> http://www.html5rocks.com/en/tutorials/webgl/typed_arrays/ may be a >> useful reference. >> >> If you're handling streaming data then presumably you're receiving >> multiple ArrayBuffers, one after the other. You should create one >> DataView per buffer. The only challenge is properly handling the >> boundary from one buffer to the next, if the boundary is within an >> element like a uint16 or uint32. >> >> -Ken > > > > > -- > -kg _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
