Hi guys,

It's me again... still having some issues pop up getting started, but I remain hopeful I'll stop needing to ask so many questions soon.

I'm trying to use std.bitmanip.read; however, am having some issues using it. For basic testing I'm just trying to use:

    read!double(endianess, ubyteArr).writeln;

endianess is an Endian from std.system, and ubyteArr is an 8 byte ubyte[].

When I run this I get:

Error: template std.bitmanip.read cannot deduce function from argument types !(double)(Endian, ubyte[]), candidates are:
    std.bitmanip.read(T, Endian endianness = Endian.bigEndian, R)(ref R range) if (canSwapEndianness!T && isInputRange!R && is(ElementType!R : const(ubyte)))
dmd failed with exit code 1.


Clearly that didn't work, so I tried excluding the endianess:

    read!double(ubyteArr).writeln;

and that does work! But its the wrong byte order, so its incorrect anyways.

I went to std.bitmanip to look for unittests using the Endian, and the only one that does uses read!(T, endianness), which needs endianness to be known at compile time, which I don't have.

Any suggestions?

On Saturday, 7 November 2015 at 03:19:44 UTC, Charles wrote:
> Hi guys,
>
> It's me again... still having some issues pop up getting started, but I remain hopeful I'll stop needing to ask so many questions soon.
>
> I'm trying to use std.bitmanip.read; however, am having some issues using it. For basic testing I'm just trying to use:
>
>     read!double(endianess, ubyteArr).writeln;
>
> endianess is an Endian from std.system, and ubyteArr is an 8 byte ubyte[].
>
> When I run this I get:
>
> Error: template std.bitmanip.read cannot deduce function from argument types !(double)(Endian, ubyte[]), candidates are:
>     std.bitmanip.read(T, Endian endianness = Endian.bigEndian, R)(ref R range) if (canSwapEndianness!T && isInputRange!R && is(ElementType!R : const(ubyte)))
> dmd failed with exit code 1.
>
>
> Clearly that didn't work, so I tried excluding the endianess:
>
>     read!double(ubyteArr).writeln;
>
> and that does work! But its the wrong byte order, so its incorrect anyways.
>
> I went to std.bitmanip to look for unittests using the Endian, and the only one that does uses read!(T, endianness), which needs endianness to be known at compile time, which I don't have.
>
> Any suggestions?

You must create a classic run-time branch:

---
if(endianess == Endian.bigEndian)
   read!(Endian.bigEndian, double)(ubyteArr).writeln;
else
   read!(Endian.littleEndian, double)(ubyteArr).writeln;
---

or in the same fashion use a final switch.

On Saturday, 7 November 2015 at 03:19:44 UTC, Charles wrote:
> Hi guys,
>
> It's me again... still having some issues pop up getting started, but I remain hopeful I'll stop needing to ask so many questions soon.
>
> I'm trying to use std.bitmanip.read; however, am having some issues using it. For basic testing I'm just trying to use:
>
>     read!double(endianess, ubyteArr).writeln;
>
> endianess is an Endian from std.system, and ubyteArr is an 8 byte ubyte[].
>
> When I run this I get:
>
> Error: template std.bitmanip.read cannot deduce function from argument types !(double)(Endian, ubyte[]), candidates are:
>     std.bitmanip.read(T, Endian endianness = Endian.bigEndian, R)(ref R range) if (canSwapEndianness!T && isInputRange!R && is(ElementType!R : const(ubyte)))
> dmd failed with exit code 1.
>
>
> Clearly that didn't work, so I tried excluding the endianess:
>
>     read!double(ubyteArr).writeln;
>
> and that does work! But its the wrong byte order, so its incorrect anyways.
>
> I went to std.bitmanip to look for unittests using the Endian, and the only one that does uses read!(T, endianness), which needs endianness to be known at compile time, which I don't have.
>
> Any suggestions?

Cheat!

T read(T,R)(Endian endianness , R r)
{
         if(endianness == Endian.bigEndian)
                return std.bitmanip.read!(T,Endian.bigEndian,R)(r);
         else if (endianness == Endian.littleEndian)
                return std.bitmanip.read!(T,Endian.littleEndian,R)(r);
}

but...
you are on a little endian system (bigEndian gave wrong byte order )
you don't need to use bitmanip.read type repainting will work.
ubyte[] r = [ /* ... */ ];
double d = *cast(double*)r.ptr;

On Saturday, 7 November 2015 at 03:53:14 UTC, Nicholas Wilson wrote:
> On Saturday, 7 November 2015 at 03:19:44 UTC, Charles wrote:
>> Hi guys,
>>
>> It's me again... still having some issues pop up getting started, but I remain hopeful I'll stop needing to ask so many questions soon.
>>
>> I'm trying to use std.bitmanip.read; however, am having some issues using it. For basic testing I'm just trying to use:
>>
>>     read!double(endianess, ubyteArr).writeln;
>>
>> endianess is an Endian from std.system, and ubyteArr is an 8 byte ubyte[].
>>
>> When I run this I get:
>>
>> Error: template std.bitmanip.read cannot deduce function from argument types !(double)(Endian, ubyte[]), candidates are:
>>     std.bitmanip.read(T, Endian endianness = Endian.bigEndian, R)(ref R range) if (canSwapEndianness!T && isInputRange!R && is(ElementType!R : const(ubyte)))
>> dmd failed with exit code 1.
>>
>>
>> Clearly that didn't work, so I tried excluding the endianess:
>>
>>     read!double(ubyteArr).writeln;
>>
>> and that does work! But its the wrong byte order, so its incorrect anyways.
>>
>> I went to std.bitmanip to look for unittests using the Endian, and the only one that does uses read!(T, endianness), which needs endianness to be known at compile time, which I don't have.
>>
>> Any suggestions?
>
> Cheat!
>
> T read(T,R)(Endian endianness , R r)
> {
>          if(endianness == Endian.bigEndian)
>                 return std.bitmanip.read!(T,Endian.bigEndian,R)(r);
>          else if (endianness == Endian.littleEndian)
>                 return std.bitmanip.read!(T,Endian.littleEndian,R)(r);
> }

Thanks!

> but...
> you are on a little endian system (bigEndian gave wrong byte order )

The actual use case is reading a binary file of unknown endianness. I don't think I'm that fortunate sadly.

On Saturday, 7 November 2015 at 03:19:44 UTC, Charles wrote:
> Hi guys,
>
> It's me again... still having some issues pop up getting started, but I remain hopeful I'll stop needing to ask so many questions soon.
>
> I'm trying to use std.bitmanip.read; however, am having some issues using it. For basic testing I'm just trying to use:
>
>     read!double(endianess, ubyteArr).writeln;
>
> endianess is an Endian from std.system, and ubyteArr is an 8 byte ubyte[].
>
> When I run this I get:
>
> Error: template std.bitmanip.read cannot deduce function from argument types !(double)(Endian, ubyte[]), candidates are:
>     std.bitmanip.read(T, Endian endianness = Endian.bigEndian, R)(ref R range) if (canSwapEndianness!T && isInputRange!R && is(ElementType!R : const(ubyte)))
> dmd failed with exit code 1.
>

You're passing endianess as a function argument, but the signatures in the error says it's supposed to be a template argument. Did you try this?

read!(double, endianess)(ubyteArr);

On Saturday, 7 November 2015 at 03:19:44 UTC, Charles wrote:

>
> I went to std.bitmanip to look for unittests using the Endian, and the only one that does uses read!(T, endianness), which needs endianness to be known at compile time, which I don't have.

Missed this in my previous reply.

On Saturday, 7 November 2015 at 04:25:00 UTC, Mike Parker wrote:
> Missed this in my previous reply.

No problem. I appreciate you taking the time to help me either way :)