220 31028 <06e829ca-417b-470c-95ca-c661e8752f79@isocpp.org> article
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Subject: Re: compressed std::bitset<N>
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Hi Vicente,

I think the Bitset2 <https://github.com/ClaasBontus/bitset2>library by 
Claas Bontus provides what you are looking for. It's like std::bitset but 
with enhanced functionality. It let's you set the underlying integral type 
of the bitset. In fact, it defaults to uint8_t, uint16_t, or uint32_t if N bits 
fit into those integers. I would like this functionality added to 
std::bitset but, as you said, it would probably be a breaking change.

Riccardo

On Thursday, February 16, 2017 at 7:04:53 AM UTC, Vicente J. Botet Escriba 
wrote:
>
> Hi,
>
> I wanted to use bitset<8>, bitset<16>, bitset<32> to represent the mask 
> of 8,16 and 32 bits respectively but the sizeof them is 64 bits on the  
> systems I've tested.
>
> Wondering if others have suffered already of this situation. 
>
> How do you fill about adding a constraint on the implementation, so that 
> the sizeof shall be respectively 8, 16, 32 bits.
>
> If this is not backward compatible, would it be worth to define a 
> different type?
>
>
> Vicente
>

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<div dir=3D"ltr">Hi Vicente,<div><br></div><div><font size=3D"2" face=3D"ar=
ial, sans-serif">I think the <a href=3D"https://github.com/ClaasBontus/bits=
et2">Bitset2 </a>library by Claas Bontus provides what you are looking for.=
 It&#39;s like std::bitset but with enhanced functionality. It let&#39;s yo=
u set the underlying integral type of the bitset. In fact, it=C2=A0<span st=
yle=3D"color: rgb(51, 51, 51);">defaults to uint8_t, uint16_t, or uint32_t=
=C2=A0</span><span style=3D"color: rgb(51, 51, 51);">if N</span><span style=
=3D"color: rgb(51, 51, 51);">=C2=A0bits fit into those integers.</span>=C2=
=A0I would like this functionality added to std::bitset but, as you said, i=
t would probably be a breaking change.</font></div><div><br></div><div>Ricc=
ardo<br><br>On Thursday, February 16, 2017 at 7:04:53 AM UTC, Vicente J. Bo=
tet Escriba wrote:<blockquote class=3D"gmail_quote" style=3D"margin: 0;marg=
in-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;">
 =20

   =20
 =20
  <div bgcolor=3D"#FFFFFF" text=3D"#000000">
    <p><font size=3D"+1">Hi,</font></p>
    <p><font size=3D"+1">I wanted to use bitset&lt;8&gt;,</font><font size=
=3D"+1"> bitset&lt;16&gt;,</font><font size=3D"+1">
        bitset&lt;32&gt; to represent the mask of 8,16 and 32 bits
        respectively but the sizeof them is 64 bits on the=C2=A0 systems I&=
#39;ve
        tested.</font></p>
    <p><font size=3D"+1">Wondering if others have suffered already of this
        situation. <br>
      </font></p>
    <p><font size=3D"+1">How do you fill about adding a constraint on the
        implementation, so that the sizeof shall be respectively 8, 16,
        32 bits.</font></p>
    <p><font size=3D"+1">If this is not backward compatible, would it be
        worth to define a different type?<br>
      </font></p>
    <p><font size=3D"+1"><br>
      </font></p>
    <p><font size=3D"+1">Vicente<br>
      </font></p>
  </div>

</blockquote></div></div>

<p></p>

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