Le 12 juil. 2013 à 08:41, Vincent Habchi a écrit :
> Hi!
>
> Sorry for this late answer, I was a bit swamped lately.
>
>> NSData wouldn't let you, but NSMutableData would, with methods like
>> appendBytes:length:, appendData:, increaseLengthBy:, etc. The underlying
>> buffer might have to m
Hi!
Sorry for this late answer, I was a bit swamped lately.
> NSData wouldn't let you, but NSMutableData would, with methods like
> appendBytes:length:, appendData:, increaseLengthBy:, etc. The underlying
> buffer might have to move around if it cannot be extended in place, just as
> it would
On Jul 8, 2013, at 18:04 , Jens Alfke wrote:
>
> On Jul 7, 2013, at 1:37 PM, Frederick Bartram wrote:
>
>> Have you tried using NSData to store C-arrays?
>
> Or alternatively use NSPointerValue to wrap a pointer to a malloc’ed C array
> as an object.
It seems to me that an array of float
On 8 Jul 2013, at 18:14, Andy Lee wrote:
> On Jul 8, 2013, at 1:08 PM, Boyd Collier wrote:
>> Your suggestion sounded worth learning about, but it appears that there's no
>> such creature as NSPointerValue.
>
> I'm guessing Jens meant +[NSValue valueWithPointer:].
>
>> Did you perhaps mea
On Jul 8, 2013, at 11:08 AM, Boyd Collier wrote:
> Your suggestion sounded worth learning about, but it appears that there's no
> such creature as NSPointerValue. Did you perhaps mean NSPointerArray?
I suspect it was instead NSValue and pointerValue/setPointerValue to which he
was referring.
On Jul 8, 2013, at 12:30 PM, Vincent Habchi wrote:
> On 8 juil. 2013, at 18:04, Jens Alfke wrote:
>> On Jul 7, 2013, at 1:37 PM, Frederick Bartram wrote:
>>
>>> Have you tried using NSData to store C-arrays?
>
> No, since my initial problem was to be able to extend the buffer as the
> number
On Jul 8, 2013, at 1:08 PM, Boyd Collier wrote:
> Your suggestion sounded worth learning about, but it appears that there's no
> such creature as NSPointerValue.
I'm guessing Jens meant +[NSValue valueWithPointer:].
> Did you perhaps mean NSPointerArray?
I'm guessing not, since NSPointerArr
Your suggestion sounded worth learning about, but it appears that there's no
such creature as NSPointerValue. Did you perhaps mean NSPointerArray?
On Jul 8, 2013, at 9:04 AM, Jens Alfke wrote:
>
> On Jul 7, 2013, at 1:37 PM, Frederick Bartram wrote:
>
>> Have you tried using NSData to s
On 8 juil. 2013, at 18:04, Jens Alfke wrote:
> On Jul 7, 2013, at 1:37 PM, Frederick Bartram wrote:
>
>> Have you tried using NSData to store C-arrays?
No, since my initial problem was to be able to extend the buffer as the number
of primitive read grew. NSData would not do that. Alternatively
On Jul 7, 2013, at 1:37 PM, Frederick Bartram wrote:
> Have you tried using NSData to store C-arrays?
Or alternatively use NSPointerValue to wrap a pointer to a malloc’ed C array as
an object.
—Jens
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> Is there any hope in the future to be able to store simple types like int or
> floats in NSArrays?
Have you tried using NSData to store C-arrays?
*-
* Frederick Bartram
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*/
smime.p7s
De
On Jul 7, 2013, at 1:08 AM, Vincent Habchi wrote:
> My initial reasoning was very (too) simple: I have a 20 MB file made up of
> strings, if I store those strings in objects, even with a small overhead, it
> should not top 30 or 40 MB. It turned out I was plainly wrong, at least the
> way I i
And while we're on the subject of speed, you're already dealing with threads,
you're already prefixing the values with a count, if you get to a format where
values in the input file are fixed-length, then you can find sections 2 & 3
without reading 1 & 2, so you could load the sections in parall
On Jul 7, 2013, at 10:38 AM, Vincent Habchi wrote:
> Oh, just that since I moved from plain BSD/Qt3 to MacOS/Cocoa, I swore not to
> write any line of C++ ever again. But that’s just a personal commitment ;)
If Qt is the majority of your experience with C++, then I understand wanting to
avoid i
Hi!
You’re right to point that CFtypes exist: I often overlook these and that’s
stupid of me.
> Why? What's wrong with a simple array?
Nothing. Well, at first, I was looking for a self expanding array, given that I
didn’t know the size beforehand.
> (Or, I would argue, though it's not a popul
On Jul 7, 2013, at 1:33 AM, Vincent Habchi wrote:
> Is there any hope in the future to be able to store simple types like int or
> floats in NSArrays?
Why? What's wrong with a simple array?
(Or, I would argue, though it's not a popular strategy, what's wrong with
std::vector?)
Now if you real
Sent from my iPhone
On 2013/07/07, at 16:33, Vincent Habchi wrote:
> Hi!
> Thanks to all for your quick and kind answers.
>
>> You're comparing apples to oranges.
>
> That’s a nice way of putting it!
>
>> You were storing strings for each numeric value, now you're storing doubles.
>
> Ac
Quincey,
> Each NSString has at least 4 bytes of overhead (the 'isa' pointer); each
> character is UTF-16; each object is a multiple of 16 bytes. Your values may
> not fit in the remaining 12 bytes of the smallest object (an input format
> something like '0.xe-nn', which isn't an unlikely forma
Hi!
Thanks to all for your quick and kind answers.
> You're comparing apples to oranges.
That’s a nice way of putting it!
> You were storing strings for each numeric value, now you're storing doubles.
Actually just floats, in order to save space.
> You could have tried NSNumber objects inste
On Jul 6, 2013, at 23:06 , Vincent Habchi wrote:
> instead of [myMutableArray add:[[NSString stringFromCString:… encoding:…]
> componentsSeparatedBy:@", "]], I just wrote: sscanf (myLine, "%f, %f, %f", &t
> [0], &t [1], &t [2])
> How come I get such a large discrepancy in memory usage between
On Jul 7, 2013, at 1:06 AM, Vincent Habchi wrote:
> At first, the TIN file didn’t include the exact number of
> vertices/normals/triangles, so I had to decode the whole file in order to
> know how large a buffer I should allocate to store each of the three data
> types. Meanwhile I did record t
The short answer is yes the overhead of an object versus a primitive
value is huge.
The longer answer is that however tiny you think the difference might
be, you need to multiply it by somewhere between 200,000 and 600,000
to really get a sense for the difference in context. For the same
reasons t
Hi everybody,
the tiny iOS app I work on currently begins by decoding 3D data in the form of
a TIN: vertices, normals then triangles. There are about 200 000 of the two
formers, and 400 000 of the latters (needless to say, at a later stage, I am
going to improve speed by using some kind of tili
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