On Saturday, 2 September 2017 at 07:20:07 UTC, kinke wrote:

> struct int24 {
>     ubyte[3] _payload;
> }
>
> static assert(int24.sizeof == 3);
> static assert(int24.alignof == 1);
>
> Making absolute sense. ubytes don't need any specific alignment to be read efficiently.

Yes, that does make sense. It doesn't make sense that I didn't realize it.

On Saturday, 2 September 2017 at 00:43:00 UTC, Nicholas Wilson wrote:
> On Friday, 1 September 2017 at 22:10:43 UTC, Biotronic wrote:
>> struct int24 {
>>     ubyte[3] _payload;
>>
>>     this(int x) {
>>         value = x;
>>     }
>>
>>     ...
>> }
>
> You may also want to put an align(1) on it so that you dont waste 25% of the allocated memory in an array of int24's

The very first test in my code checks this:

    int24[3] a;
    assert(a.sizeof == 9);

On the other hand, using Mir's well-tested code instead of something I hacked together in 10 minutes is probably a good idea.

--
  Biotronic

On Friday, 1 September 2017 at 19:39:14 UTC, EntangledQuanta wrote:
> Is there a way to create a 24-bit int? One that for all practical purposes acts as such? This is for 24-bit stuff like audio. It would respect endianness, allow for arrays int24[] that work properly, etc.

If you need to perform math on integer audio, I strongly suggest to use int32 for this purpose to avoid performance degradation, then convert back to int24 when you're finished. Probably going to add such feature into my PCM library.

On Saturday, 2 September 2017 at 03:29:20 UTC, EntangledQuanta wrote:
> On Saturday, 2 September 2017 at 02:49:41 UTC, Ilya Yaroshenko wrote:
>> On Friday, 1 September 2017 at 19:39:14 UTC, EntangledQuanta wrote:
>>> Is there a way to create a 24-bit int? One that for all practical purposes acts as such? This is for 24-bit stuff like audio. It would respect endianness, allow for arrays int24[] that work properly, etc.
>>
>> Hi,
>>
>> Probably you are looking for bitpack ndslice topology:
>> http://docs.algorithm.dlang.io/latest/mir_ndslice_topology.html#.bitpack
>>
>> sizediff_t[] data;
>> // creates a packed signed integer slice with max allowed value equal to `2^^24 - 1`.
>> auto packs = data[].sliced.bitpack!24;
>>
>> packs has the same API as D arrays
>>
>> Package is Mir Algorithm
>> http://code.dlang.org/packages/mir-algorithm
>>
>> Best,
>> Ilya
>
> Thanks. Seems useful.

Just added `bytegroup` topology. Released in v0.6.12 (will be available in DUB after few minutes.)

http://docs.algorithm.dlang.io/latest/mir_ndslice_topology.html#bytegroup

It is faster for your task then `bitpack`.

Best regards,
Ilya

On Friday, 1 September 2017 at 22:10:43 UTC, Biotronic wrote:
> On Friday, 1 September 2017 at 19:39:14 UTC, EntangledQuanta wrote:
>> Is there a way to create a 24-bit int? One that for all practical purposes acts as such? This is for 24-bit stuff like audio. It would respect endianness, allow for arrays int24[] that work properly, etc.
>
> I haven't looked at endianness beyond it working on my computer. If you have special needs in that regard, consider this a starting point:

big endian is indeed problematic.

>     @property
>     int value(int x) {
>         _payload = (cast(ubyte*)&x)[0..3];
>         return value;
>     }
>

will not work on big endian machine.

    version(BigEndian)
        _payload = (cast(ubyte*)&x)[1..4];

On Sunday, 3 September 2017 at 04:01:34 UTC, Ilya Yaroshenko wrote:
> On Saturday, 2 September 2017 at 03:29:20 UTC, EntangledQuanta wrote:
>> On Saturday, 2 September 2017 at 02:49:41 UTC, Ilya Yaroshenko wrote:
>>> On Friday, 1 September 2017 at 19:39:14 UTC, EntangledQuanta wrote:
>>>> Is there a way to create a 24-bit int? One that for all practical purposes acts as such? This is for 24-bit stuff like audio. It would respect endianness, allow for arrays int24[] that work properly, etc.
>>>
>>> Hi,
>>>
>>> Probably you are looking for bitpack ndslice topology:
>>> http://docs.algorithm.dlang.io/latest/mir_ndslice_topology.html#.bitpack
>>>
>>> sizediff_t[] data;
>>> // creates a packed signed integer slice with max allowed value equal to `2^^24 - 1`.
>>> auto packs = data[].sliced.bitpack!24;
>>>
>>> packs has the same API as D arrays
>>>
>>> Package is Mir Algorithm
>>> http://code.dlang.org/packages/mir-algorithm
>>>
>>> Best,
>>> Ilya
>>
>> Thanks. Seems useful.
>
> Just added `bytegroup` topology. Released in v0.6.12 (will be available in DUB after few minutes.)
>
> http://docs.algorithm.dlang.io/latest/mir_ndslice_topology.html#bytegroup
>
> It is faster for your task then `bitpack`.
>
> Best regards,
> Ilya

Thanks! I might end up using this. Is this basically just a logical mapping(cast(int)bytes[i*3]) & 0xFFFFFF) type of stuff or is there more of a performance hit?

I could do the mapping myself if that is the case as I do not need much of a general solution. I'll probably be using in a just a few lines of code. It just needs to be nearly as fast as direct access.

On Sunday, 3 September 2017 at 23:30:43 UTC, EntangledQuanta wrote:
> On Sunday, 3 September 2017 at 04:01:34 UTC, Ilya Yaroshenko wrote:
>> On Saturday, 2 September 2017 at 03:29:20 UTC, EntangledQuanta wrote:
>>> On Saturday, 2 September 2017 at 02:49:41 UTC, Ilya Yaroshenko wrote:
>>>> [...]
>>>
>>> Thanks. Seems useful.
>>
>> Just added `bytegroup` topology. Released in v0.6.12 (will be available in DUB after few minutes.)
>>
>> http://docs.algorithm.dlang.io/latest/mir_ndslice_topology.html#bytegroup
>>
>> It is faster for your task then `bitpack`.
>>
>> Best regards,
>> Ilya
>
> Thanks! I might end up using this. Is this basically just a logical mapping(cast(int)bytes[i*3]) & 0xFFFFFF) type of stuff or is there more of a performance hit?
>
> I could do the mapping myself if that is the case as I do not need much of a general solution. I'll probably be using in a just a few lines of code. It just needs to be nearly as fast as direct access.

The implementation can be found here
https://github.com/libmir/mir-algorithm/blob/master/source/mir/ndslice/iterator.d
It uses unions and byte loads. The speed should be almost the same as direct access.